JP6992619B2 - Position estimation device, position estimation program, and position estimation method - Google Patents

Description

The present invention relates to a position estimation device, a position estimation program, and a position estimation method.

In recent years, customer behavior analysis utilizing location information has been performed for advertisement distribution in commercial facilities and layout arrangement in stores. Generally, an example using GPS (Global Positioning System) is known for acquiring position information. However, it is often difficult for GPS to grasp the position information of an object indoors. On the other hand, for example, a beacon can be used indoors and can be installed at low cost, so that it is often used for acquiring location information.

In order to utilize the beacon, it is necessary to acquire the beacon identifier and the position information related to the installation position of the beacon in advance and make them available, but the position information related to the installation position of the beacon must be obtained in advance. There are cases where it has not been obtained. Therefore, it may be required to accurately grasp the position information (described as the position information of the beacon) related to the installation position of the beacon and to create a database.

The signal transmitted from the beacon does not always include the position information of the beacon. Therefore, the terminal capable of receiving the signal from the beacon cannot always directly acquire the position information of the beacon at the time when the signal is received from the beacon.

Here, as a method of acquiring the position information of the object including the beacon, for example, a method of detecting the position of the object by using signals from a plurality of nodes whose positions are known at the same time is known. .. However, if the object is moving or if the signals transmitted from the plurality of nodes are not transmitted at the same time, the accuracy of estimating the position of the object may decrease.

On the other hand, for example, a method is known in which a weight is determined according to the irradiation range of a signal from a node whose position can be grasped to an object, and the weighted average of the signal is used to detect the position of the object. However, when the acquisition interval of each signal from a plurality of nodes is large, the estimated position of the object may be different from the actual position of the object.

Japanese Unexamined Patent Publication No. 2013-073333

Wireless Position Detection Technology, Measurement and Control, 48 (7), 560-564, 2009

The node used to estimate the position of a transmitter such as a beacon may not always be in a specified position, and even if there is a node with a specified position, it is in a position where a signal can be received from the beacon. It may not always be. Therefore, a method of estimating the position of the beacon by using, for example, a mobile terminal, which can receive a signal from the beacon and can acquire the position information from the node whose position is specified, can be considered. In this case, as a method for estimating the position of the beacon using the terminal, the position information of the beacon acquired by the terminal before and after receiving the signal from the beacon is used to estimate the position of the beacon. Is conceivable. In this case, the time when the signal from the beacon is received, the information on the strength of the signal, the time when the position information is acquired, and the position information, which are acquired by the terminal, can be used for the position estimation.

However, the terminal does not always move at a constant speed, and there are cases where the terminal stays. Therefore, there are cases where it is not appropriate to estimate the position of the beacon using the time before and after receiving the beacon and the position information obtained at that time. On the other hand, the closer the position of each position information acquired at the time before and after receiving the beacon is to each other, the closer the position of each position information is to the position of the beacon, and the terminal stays. It is not appropriate to exclude cases.

An object of one aspect of the present invention is to prevent deterioration of the accuracy of position estimation even when the movement of the terminal before and after receiving a signal from the transmitter includes stagnation.

The position estimation device according to one embodiment includes an acquisition unit and a position estimation unit. The acquisition unit acquires the reception time when the terminal receives the signal from the transmitter and the strength of the signal received by the terminal. Further, the acquisition unit receives the first position time information acquired at the first point at the first time before the reception time by the terminal and the second point at the second time after the reception time by the terminal. The second position time information acquired in is acquired. The position estimation unit calculates the average moving speed between the first point and the second point of the terminal from the first position time information and the second position time information. The position estimation unit is between the first time and the reception time when the average moving speed is equal to or less than the predetermined value and the distance between the first point and the second point is equal to or more than the predetermined distance. The correction is performed for at least one of the first time interval and the second time interval between the reception time and the second time. Further, the position estimation unit estimates the position of the terminal at the reception time based on at least one of the first time interval and the second time interval after the correction, and estimates the position of the transmitter based on the estimation. I do.

Even when the movement of the terminal before and after receiving the signal from the transmitter includes stagnation, the deterioration of the accuracy of the position estimation is prevented.

It is a figure which shows an example of the structure of the position estimation system which concerns on 1st Embodiment. It is a figure for demonstrating the function of the functional block of the position estimation apparatus which concerns on 1st Embodiment, and the processing contents. It is a figure for demonstrating the correspondence between the locus of movement of a terminal, and the locus extraction information. It is a figure which shows an example of the position estimation method using coordinates and time interval. It is a figure which shows an example of the retention of a terminal. It is a figure which shows an example of passing through a terminal. It is a flowchart of the process by the position estimation apparatus which concerns on 1st Embodiment. It is a figure which illustrates the reception information and the position time information acquired by a data acquisition unit. , Is a diagram illustrating the locus extraction information generated by the locus extraction unit. It is a flowchart of the process by the position estimation part in 1st Embodiment. It is a figure which illustrates the locus information generated based on the processing of a position estimation part. It is a figure which shows the comparative example of each accuracy in the case of performing the position estimation using the prior art, and the case of performing the position estimation in the first embodiment. It is a figure which shows an example of the structure of the position estimation system which concerns on 2nd Embodiment. It is a figure for demonstrating the processing content of each functional block of the position estimation apparatus which concerns on 2nd Embodiment. It is a flowchart of the process by the position estimation apparatus which concerns on 2nd Embodiment. It is a flowchart of the process by the error determination part in 2nd Embodiment. It is a figure for demonstrating an example of the error determination processing by the position estimation apparatus which concerns on 2nd Embodiment. It is a figure for demonstrating an example of the error determination processing by the position estimation apparatus which concerns on 2nd Embodiment. It is a figure which shows an example of the effect by performing the error determination processing in 2nd Embodiment. It is a figure which shows an example of the structure of the position estimation system which concerns on 3rd Embodiment. It is a figure for demonstrating the processing content of each functional block of the position estimation apparatus 2C which concerns on 3rd Embodiment. It is a flowchart of the process by the position estimation apparatus which concerns on 3rd Embodiment. It is a flowchart of the process by the error position estimation apparatus in 3rd Embodiment. It is a figure which shows the example of the error position estimation process in 3rd Embodiment. It is a figure which shows the example of the error position estimation process in 3rd Embodiment. It is a figure which shows the example of the error position estimation process in 3rd Embodiment. It is a figure which shows the example of the error position estimation process in 3rd Embodiment. It is a figure which shows an example of the effect obtained in the position estimation by the position estimation apparatus 2C which concerns on 3rd Embodiment. It is a figure which shows the position estimation method which concerns on other Embodiment 1. It is a figure which shows the functional block of the position estimation apparatus which concerns on other Embodiment 1. It is a figure which shows the functional block of the position estimation apparatus which concerns on other Embodiment 2. It is a figure which shows an example of the processing by the position estimation apparatus which concerns on other Embodiment 2. It is a figure which shows an example of the hardware configuration for realizing each function of each position estimation apparatus which concerns on Embodiments 1, 2, 3 and other Embodiments 1, 2, 3, 4.

(First Embodiment)
FIG. 1 is a diagram showing an example of the configuration of the position estimation system 1A according to the present embodiment. The position estimation system 1A according to the present embodiment includes a position estimation device 2A, a movement history database 3, a position information master database 4, and the like. The movement history database 3 and the position information master database 4 are connected to the position estimation device 2A, respectively. Further, the position estimation system 1 includes one or more terminals 6 that are wirelessly connected to the movement history database 3 via the network 5. The network 5 is a wired or wireless network. Further, the position estimation system 1A includes one or more sensors 7 and a beacon 8 that can wirelessly communicate with each terminal 6 via the network 5. Such a sensor 7 or a beacon 8 is also referred to as a transmitter. The sensor 7 or the beacon 8 may be connected to the movement history database 3 so as to be able to communicate with each other by wire or wirelessly.

In the example shown in FIG. 1, the position estimation device 2A, the movement history database 3, and the position information master database 4 are represented as separate ones, but the position estimation device 2A is the movement history database 3 or the position information. It may include the master database 4.

As shown in FIG. 1, the position estimation device 2A includes functional blocks such as a data acquisition unit 20, a trajectory extraction unit 21, and a position estimation unit 22. These functional blocks will be described later.

The movement history database 3 is stored in, for example, storage in cloud computing. It is assumed that the data recorded in the movement history database 3 is the information received from each terminal 6 by the movement history database 3 in the present embodiment, and in this information, each of these terminals 6 is from the sensor 7 or the beacon 8. The received data is included. However, the present invention is not limited to this, and the sensor 7 or the beacon 8 may transmit information including data received from the terminal 6 to the movement history database 3.

The location information master database 4 is stored in a storage device or the like for managing and storing location information. In the position information master database 4, the coordinates of the position where the sensor in a broad sense such as the sensor 7 and the beacon 8 are arranged, or the coordinates of the position where the sensor is presumed to be arranged are recorded.

The terminal 6 is, for example, a mobile phone, a smartphone, a tablet, a car navigation system, a driver support system in a train, or the like. Each terminal 6 is given a unique ID (IDentification). The terminal 6 receives signals from the sensor 7 and the beacon 8 via the network 5 and transmits the data to the movement history database 3. Further, the terminal 6 appropriately transmits a signal to the sensor 7 or the beacon 8. The signal here is a radio wave modulated for the exchange of information wirelessly.

In the present embodiment, it is assumed that the sensor 7 knows the coordinates of its attached position. The sensor 7 transmits a signal corresponding to the information of the coordinates. Then, the terminal 6 receives the signal from the sensor 7 to obtain the coordinate information of the installation position of the sensor 7. If the installation position of the sensor 7 is not specified, the sensor 7 may be the target of the position estimation described below.

In the present embodiment, the beacon 8 is a target for estimating where the position where the beacon 8 is attached is. However, the beacon 8 may have a specified position where it is attached. In this case, for example, in order to confirm the mounting position of the beacon, the position may be estimated as described later. Each beacon 8 is given a unique identifier. Then, the beacon 8 transmits a signal corresponding to its own identifier, and the terminal 6 that receives the signal acquires the identifier of the beacon 8.

When the terminal 6 acquires the coordinates of the installation position from the sensor 7, the terminal 6 transmits the information including the coordinates and the information of the acquired time (also referred to as the position time information) to the movement history database 3 together with its own ID. do. The combination of the position / time information and the ID is also referred to as the position / time information below.

Here, instead of the time when the terminal 6 acquires the coordinates from the sensor 7, the terminal 6 may transmit the following time information to the movement history database 3. For example, the sensor 7 transmits the information related to the time when the information of the coordinates is transmitted to the terminal 6 together with the information of the coordinates, and the terminal 6 transfers the information related to the time received at this time to the movement history database 3. You may send it. It should be noted that such time and coordinate information, or information in which the ID of the terminal 6 is combined with the information, is also described as position time information.

The terminal 6 can acquire the identifier of the beacon 8 from the beacon 8 within the range of the radio wave. The terminal 6 relates to its own ID, the identifier of the beacon 8, the strength of the radio wave (also referred to as the signal strength) from the beacon 8 when acquiring the identifier of the beacon 8, and the time when the signal is received from the beacon 8. Information is transmitted to the movement history database 3. Here, the information transmitted from the terminal 6 to the movement history database 3 including the identifier from the beacon 8 is also described as the received information.

Here, the intensity of the radio wave from the beacon 8 received by the terminal 6 increases as the beacon 8 and the terminal 6 are closer to each other, so that it is an index indicating the proximity of the terminal 6 to the beacon 8. Therefore, instead of the strength of the signal from the beacon 8, the terminal 6 may transmit a numerical value of the proximity from the beacon 8 to the movement history database 3.

When the terminal 6 continuously receives signals from the same beacon 8, the terminal 6 holds the information corresponding to one of the signals and deletes the information corresponding to the other signals. This is to prevent extra data from being accumulated in the terminal 6. It is assumed that the information corresponding to the plurality of signals received from the same beacon 8 by the terminal 6 according to the present embodiment is the information corresponding to the signal first received from the beacon 8. However, the present invention is not limited to this, and for example, the terminal 6 corresponds to the information corresponding to the last signal among the information corresponding to a plurality of signals continuously received from the same beacon 8, or the signal arbitrarily selected. The information may be left and the information corresponding to the other signals may be deleted. The terminal 6 includes the information corresponding to the plurality of signals continuously received from the same beacon 8 in the received information and transmits the information to the movement history database 3. This is to prevent extra data from being accumulated in the movement history database 3 and to prevent a large amount of data from being transmitted on the network and increasing traffic. When the terminal 6 according to the present embodiment continuously receives a plurality of signals from the same beacon 8, the received information transmitted to the movement history database 3 is the information corresponding to the signal first received from the beacon 8. Is included.

FIG. 2 is a diagram for explaining the functions and processing contents of the functional blocks of the position estimation device 2A according to the present embodiment. The data acquisition unit 20 included in the position estimation device 2A reads the received information including the identifier of the beacon 8 whose position is to be estimated from the movement history database 3. As the beacon 8 to be the target of position estimation, for example, it is determined that it is preferable to reconfirm the position of the beacon 8 whose position is not registered in the position information master database 4 or even if the position is registered. Beacon 8. The latter is, for example, a beacon 8 in which the estimated position changes each time the position is reconfirmed. Further, the beacon 8 for which the position is estimated is not limited to the beacon 8 as described above, and may be any beacon 8. For example, it is possible to confirm the position of an arbitrary beacon 8 on a regular basis.

The data acquisition unit 20 may receive input from the user such as an identifier of the beacon 8 to be estimated of the position, and may read the received information including the identifier or the like from the position information master database 4. Alternatively, the data acquisition unit 20 refers to whether the information on the coordinates of the beacon 8 is recorded in the position information master database 4, how much the coordinates of the beacon 8 change with each update, and the like, and estimates the position based on this. The target beacon 8 may be selected.

The data acquisition unit 20 outputs the received information read from the movement history database 3 to the locus extraction unit 21.

Further, the data acquisition unit 20 reads the position time information including the ID of the terminal 6 in the received information read from the movement history database 3 from the movement history database 3.

In the example shown in FIG. 2, the position estimation device 2A estimates the position of each beacon 8 whose identifiers are p1 and p2. Therefore, the data acquisition unit 20 reads the received information having the identifiers p1 and p2 from the movement history database 3. The received information is shown to the left of the middle portion of FIG. Although the received information is represented in a table format here, the received information includes the ID of the terminal 6, the time when the terminal 6 receives the signal from the beacon 8, the identifier of the beacon 8, and the said information from the beacon 8. The signal strengths need only be associated with each other.

The data acquisition unit 20 refers to the ID in the read received information, and reads the position / time information including this ID from the movement history database 3. This ID is the ID of the terminal 6 that has received the signal from the beacon 8 whose position is to be estimated. The received information having the identifier p1 exemplified in FIG. 2 includes those having IDs id1 and id3. Therefore, the data acquisition unit 20 reads each position / time information whose IDs are id1 and id3 from the movement history database 3. Similarly, since the IDs in the received information whose identifier is p2 are id2 and id3, the data acquisition unit 20 reads the position / time information including each of these IDs from the movement history database 3.

The position-time information exemplified in FIG. 2 is represented in a table format, and the position-time information includes the ID of the terminal 6, the time when the terminal 6 receives a signal from the sensor 7, and the installation position of the sensor 7. The coordinates need only be related to each other. With reference to the position-time information in FIG. 2, it can be seen that the terminal 6 having the ID id1 has acquired the coordinates x11 from the sensor 7 at the time t11.

The locus extraction unit 21 collects the reception information and the position / time information read by the data acquisition unit 20 for each ID and sorts them in chronological order. On the right side of FIG. 2, the locus extraction unit 21 collects the received information and the position / time information for each ID, and shows the data sorted in chronological order. With reference to the data, for example, it can be seen that the terminal 6 having the ID id2 receives a signal related to the information including the coordinates x21 from the sensor 7 installed at the coordinates x21 at the time t21. Then, the terminal 6 receives the signal of the intensity v22 from the beacon 8 whose identifier is p2 at the subsequent time t22, and further receives the signal from the sensor 7 installed at the coordinate x23 at the subsequent time t23. Recognize. It can be seen that the terminal 6 subsequently receives a signal from the sensor 7 installed at the coordinate x24 at time t24.

The locus extraction unit 21 further collects this data for each beacon 8. It should be noted that this process may be performed prior to the process of collecting the received information and the position / time information for each ID. When one terminal 6 receives signals from two or more beacons 8, even if the position time information including the ID of the terminal 6 is collected for each of the received information related to these beacons 8. good.

The locus extraction unit 21 is a data in which received information and position / time information are grouped by ID and sorted in chronological order, and the position / time information including information based on the received information and each time immediately before and after the time in the received information. Extract information based on. For example, in the data shown on the right side of FIG. 2, when the ID is id2, the locus extraction unit 21 uses the line at time t22, the line at time t21 immediately before time t22, and the time t23 immediately after time t22. Extract the corresponding information in each row. In this way, the information extracted by the locus extraction unit 21 is also referred to as locus extraction information.

The position estimation unit 22 calculates and estimates the coordinates of the installation position of each beacon 8 from the locus extraction information generated by the locus extraction unit 21. Detailed processing by the position estimation unit 22 will be described later.

FIG. 3 is a diagram for explaining the correspondence between the locus of movement of the terminal 6 and the locus extraction information. The beacon 8 in the present embodiment shown in FIG. 3 is fixedly installed. Further, as shown in FIG. 3, the terminal 6 can move along the passage shown by the solid line. As shown in FIG. 3, each terminal 6 receives a signal from the sensor 7 and the beacon 8 as it moves as indicated by the broken line. The direction of the broken line arrow indicates the moving direction of the terminal. Hereinafter, the locus extraction information and the movement of the terminal 6 will be specifically described in association with each other.

In the figure on the left of FIG. 3, for example, referring to the terminal 6 having an ID of 4, the terminal 6 receives a signal from the sensor 7 at or near the point A, and the coordinates of the point A, which is the installation position of the sensor 7. You can see that you are getting. With reference to the locus extraction information, it can be seen that the terminal 6 of ID4 has acquired the coordinates (10, 10) of the point A from the sensor 7 at the time of 0 and the point A. The unit of time is, for example, seconds or minutes. Subsequently, the terminal 6 receives a signal having an intensity of 100 from the beacon 8 when the time is 40 in the movement path. Further, the terminal 6 acquires the coordinates (80, 30) of the point B from the sensor 7 at the time of 90 and the point B. Similarly, for each of the other terminals having IDs 1, 2, 3, 5, and 6, the movement route, the acquired information, the time when the information was acquired, and the like can be found from FIG. In the present embodiment, when the terminal 6 receives a signal from the sensor 7 at a certain point, the coordinates of the sensor 7 are equal to the coordinates of the point or the coordinates of the position where the distance from the point is sufficiently small. Suppose there is.

As illustrated in FIG. 3, the locus extraction information indicates the reception of the signal from the beacon 8 and the reception of the signal from the sensor 7 before and after the reception of the signal from the beacon 8 for each terminal 6. It can be seen that the data is extracted. Therefore, these data of a certain terminal 6 are described as the locus extraction information of the terminal 6.

FIG. 4 is a diagram showing an example of a position estimation method using coordinates and a time interval. Here, the position estimation method will be described with reference to the movement route, reception status, and locus extraction information of the terminal 6 of ID3 shown in FIG. The terminal 6 acquires coordinate (80, 70) information from a certain sensor 7 at a point C at time 0. After that, the terminal 6 receives a signal having an intensity of 90 from the beacon 8 having the identifier p1 at time 40. This signal is a signal related to the information of the identifier p1 of the beacon 8. After that, the terminal 6 acquires the information of the coordinates (10, 0) from another sensor 7 at the point D at the time 70.

Here, even if the locus extraction information of the terminal 6 of the ID 3 as shown in FIG. 4 is referred to, it is not always possible to obtain information on the movement route other than the information regarding each position at the time 0 and the time 70 of the terminal 6. do not have. As described above, the position estimation device 2A may not always be able to acquire information on the movement route of each terminal 6. The position estimation device 2A according to the present embodiment estimates the position of the terminal 6 at the time when the terminal 6 receives a radio wave from the beacon 8 in order to estimate the position of the beacon 8. However, in order to estimate the position where the terminal 6 receives the radio wave from the beacon 8, the position estimation device 2A must increase the sensor 7 in order to acquire the information on the movement path of the terminal 6. This may increase the amount of communication. In order to avoid such a situation, the position estimation device 2A according to the present embodiment uses the locus extraction information as shown in FIGS. Estimates the position where the signal was received. The processing from here is performed by the position estimation unit 22 described above.

In the case shown in FIG. 4, the position estimation unit 22 refers to the locus extraction information and approximates the movement path of the terminal 6 of the ID 3 by the line segment connecting the point C and the point D. Then, in the position estimation unit 22, the time 40 when the terminal 6 receives the signal from the beacon 8 of the identifier p1 is within the time between the time 0 when the terminal 6 exists at the point C and the time 70 when the terminal 6 exists at the point D. Calculate where it is located. From the locus extraction information, it can be seen that the time interval until the terminal 6 moves from the point C and receives the signal of the beacon 8 is 40, and the terminal 6 reaches the point D after receiving the signal of the beacon 8. It can be seen that the time interval up to is 30. As the position of the beacon 8 or the position where the terminal 6 is considered to have received the signal from the beacon 8, the line segment connecting the point C and the point D is generally used as the ratio of the time interval, that is, by using linear interpolation. It is conceivable that it will be internally divided by 4 to 3. However, such an internal division point is not always equal to the actual installation position of the beacon 8 or the position where the terminal 6 receives the signal from the beacon 8, as is clear from the example in FIG.

In the following, each point where the terminal 6 acquires coordinate information from the sensor 7 before and after receiving the signal from the beacon 8 will be described as a first point and a second point. Further, in the following, the time when the terminal 6 acquires the information related to the coordinates from the sensor 7 at the first point is also described as the first time. Similarly, the time when the terminal 6 acquires the information related to the coordinates from the sensor 7 at the second point is also described as the second time. Similarly, the time when the terminal 6 receives the signal from the beacon 8 is also described as the reception time. The time interval between the first time and the reception time is also described as the first time interval. Similarly, the time interval between the reception time and the second time is also described as the second time interval. Further, in the following, the internal division point means a point that internally divides the line segment connecting the first point and the second point by the ratio of the first time interval and the second time interval. ..

Here, in the present embodiment, in order to accurately estimate the position of the terminal 6 at the reception time, the retention described below is considered. FIG. 5 is a diagram showing an example of retention of the terminal 6. Here, the retention of the terminal 6 of the ID 5 will be described. The figure on the left in FIG. 5 shows the actual movement route of the terminal 6 of ID5. The solid line and the broken line here indicate the movement path of the passage and the terminal 6, respectively, as in the case of FIGS. 3 and 4. Further, each figure such as the position where the beacon 8 and the terminal 6 received the information from the sensor 7 is the same as in the case of FIGS. 3 and 4 above.

If the terminal 6 does not move for a while from the range in which the radio wave from the beacon 8 can be received, the terminal 6 may receive a plurality of signals from the beacon 8. For ease of understanding, it is assumed that the terminal 6 transmits the received information corresponding to each of the plurality of signals to the movement history database 3. Here, consider a case where the terminal 6 of the ID 5 continuously receives a plurality of signals from the same beacon 8 and transmits a plurality of received information corresponding to these signals to the movement history database 3. At this time, the locus extraction unit 21 arranges the received information from the terminal 6 and the position / time information in chronological order, and generates data as shown in the middle portion of FIG. However, the received information transmitted by the terminal 6 to the movement history database 3 in the present embodiment corresponds to the signal first received from the beacon 8, and the above assumption is for explaining the retention. ..

From the left figure in FIG. 5 and the data in the middle portion, the terminal 6 of ID5 moves along the route shown by the broken line in FIG. 5 until the time 40 after acquiring the information from the sensor 7 at the point E at the time 0. You can see that it is doing. Subsequently, after receiving the signal from the beacon 8 at time 40, the terminal 6 moves at a speed lower than the speed up to time 40, or stays at or near the same point until time 80. I understand. It can be seen that the terminal 6 moves at a speed higher than the speed from time 40 to time 80 from time 80 to time 90, and acquires coordinate information from the sensor 7 at time 90. The locus extraction information extracted for such movement of the terminal 6 is shown in the lower right of FIG.

The route derived from this locus extraction information as the movement route of the terminal 6 is a route along the line segment connecting the first point (E) and the second point (F) shown in the upper right of FIG. .. The point that can be recognized as the installation position of the beacon 8 is the point that the route represented by the line segment is internally divided according to the ratio (4: 5) of the first time interval 40 and the second time interval 50. It becomes the point G which is. However, the actual position of Beacon 8 is close to point F. If the distance between the point E and the point F is not small, or if the time spent by the terminal 6 to move from the point E to the point F is not small, the point G is from the actual installation position of the beacon 8. It can be a distant point. As described above, the accuracy of estimating the position of the beacon 8 may deteriorate due to the influence of the moving speed of the terminal 6.

In the present embodiment, the case where the average moving speed of the terminal 6 is equal to or less than a predetermined value is regarded as retention. It should be noted that this predetermined value is a value preset by the user. This predetermined value is predetermined for each type of terminal 6. For example, the terminal 6 may be a car navigation system, a mobile phone, or the like, and a predetermined value is predetermined according to each of these cases.

The position estimation unit 22 in the present embodiment refers to the locus extraction information for the terminal 6 used for the position estimation of the beacon 8, and calculates the average moving speed between the first point and the second point of the terminal 6. do. Next, the position estimation unit 22 determines whether or not the terminal 6 is stagnant from the average moving speed. The position estimation unit 22 determines that the terminal 6 is stagnant, and when the distance between the first point and the second point is a predetermined distance or more, the second time Correct the interval. In this correction, for example, when there is no stagnation, the terminal 6 is converted into a time interval or the like that is estimated to have actually taken to move. For this conversion, the movement history database 3, the location information master database 4, or another database has an unspecified amount of time in the range assumed as the installation position of the beacon 8 or near the second point. Data such as whether the terminal 6 continues to be located is retained. This data was accumulated in the vicinity of the second point and in the range where it is estimated that the beacon 8 is installed via the terminal 6 which acquired information from another beacon 8 or the sensor 7 whose installation location is specified. It may be a thing. Further, the data may be accumulated via a large number of terminals 6 that have received signals from the beacon 8 whose installation position is not specified but is expected to exist within the range. The person who sets the position estimation unit 22 or the position estimation device 2A uses this data to investigate in advance how the time interval that should take the original movement changes due to the retention, and how. Decide whether to correct to. For example, if there is statistical data that an unspecified number of terminals 6 continue to be located for an average of 100 minutes in a certain range of a distance of about 10 minutes for movement, the position estimation unit 22 is the second terminal 6 to stay. The time interval of is multiplied by 1/10. Alternatively, if there is statistical data such that the distance from one end to the other of a certain range is not large, but an unspecified number of terminals 6 stay in the range for an average of one hour, the position estimation unit 22 may use the second position estimation unit 22. For example, subtract 1 hour from the time interval of.

Here, the reason for correcting the second time interval is as follows. First, the place where the beacon 8 is installed is often a place such as a restaurant where the terminal 6 is considered to be stagnant. Further, when a plurality of signals are continuously received from the same beacon 8, the terminal 6 transmits the received information related to the first signal to the movement history database 3 and does not transmit the received information related to the other signals. Therefore, the time interval from the last signal received from the same beacon 8 to the next acquisition of coordinate information from the sensor 7 is unknown. This time interval is considered to be approximately equal to the second time interval in the absence of stagnation. Therefore, the position estimation unit 22 corrects the second time interval by using statistics such as the residence time at the relevant point.

On the contrary, when the terminal 6 transmits the received information related to the last signal among the plurality of signals continuously received from the same beacon 8 to the movement history database 3, the position estimation unit 22 is the first. Correct the time interval. In addition to these, the position estimation unit 22 may correct both the first time interval and the second time interval. Further, when the received information relates to any one of the plurality of signals received from the beacon 8, correction may be made accordingly.

In the present embodiment, even if there is a stagnation, if the distance between the first point and the second point is small, for example, if the distance is less than a predetermined distance, the second time interval is corrected. I won't get it. This is because, in this case, the range estimated as the installation position of the beacon 8 is not so wide. This is because the calculation amount of the position estimation unit 22 is not increased by not performing the correction. The predetermined distance, which is the boundary between the necessity of correction to the second time interval, is appropriately set by the user. For example, what is set as a predetermined distance is, for example, twice the allowable error when the distance between the actual installation position of the beacon 8 and the estimated position of the beacon 8 is taken as an error, or the relevant error. It is the error plus a certain value.

The position estimation device 2A according to the present embodiment is obtained by linear interpolation using the ratio of the corrected second time interval and the first time interval when the correction is performed for the second time interval. The coordinates of the interpolation point are estimated as the position of the terminal 6 at the reception time. On the other hand, when the correction is not performed for the second time interval, the position estimation device 2A obtains the internal fraction obtained by linear interpolation using the ratio of the original first time interval and the second time interval. The coordinates of the point are estimated as the position of the terminal 6 at the reception time. The coordinates of the internal division points obtained by such linear interpolation are also described as interpolation coordinates or linear interpolation coordinates. Since these linear interpolation coordinates are obtained for each terminal 6, they are also described as the linear interpolation coordinates of the terminal 6 and the interpolation coordinates of the terminal 6.

While the terminal 6 may stay, the accuracy of estimating the position of the beacon 8 may deteriorate due to the high average moving speed of the terminal 6. Such a case is described as passing. FIG. 6 is a diagram showing an example of passing through the terminal 6. The figure on the left in FIG. 6 shows the actual movement route of the terminal 6 of ID3. The solid line and the broken line here indicate the movement path of the passage and the terminal 6, respectively, as in the case of FIGS. 3 and 4. Further, the figures such as the position where the beacon 8 and the terminal 6 receive the information from the sensor 7 are the same as in the cases of FIGS. 3 and 4 above. In the center of FIG. 6, the locus extraction information of the terminal 6 of the ID 3 is shown. From the figure on the left of FIG. 6 and the locus extraction information, it can be seen that the terminal 6 of ID3 acquires the coordinate information from the sensor 7 at the point H at time 0. Then, it can be seen that the terminal 6 moves according to the movement path shown by the broken line on the left side of FIG. 6 and receives a signal of intensity 90 from the beacon 8 at time 40. Next, it can be seen that the terminal 6 has acquired coordinate information from the sensor 7 at time 70. Here, when the moving speed of the terminal 6 is high, it is considered that at least one of the distance traveled between the time 5 and the time 40 and the distance traveled between the time 40 and the time 70 is large. Here, it is assumed that both of these distances are large.

The route derived from the locus extraction information as the movement route of the terminal 6 is the route represented by the broken line shown in the right figure of FIG. In this case, the distance between the route represented by the line segment connecting the point H and the point I and the actual installation position of the beacon 8 can be large. In this case, the point estimated as the installation position of the beacon 8 is the point J on the route connecting the point H and the point I, which may be a position away from the actual installation position of the beacon 8. When the moving speed of the terminal 6 is high as described above, there is a high possibility that the accuracy of estimating the position of the beacon 8 by linear interpolation will drop.

For more accurate estimation of the installation position of the beacon 8, the position estimation device 2A assigns the weights described below to the coordinates of each internal division point of one or more terminals 6 that have received the signal from the beacon 8. do. Then, the position estimation device 2A estimates the position of the beacon 8 by calculating the weighted average of the coordinates of these internal division points.

First, the signal strength of the beacon 8 corresponds to the proximity to the beacon 8. Therefore, the higher the intensity, the closer the position where the terminal 6 receives the signal from the beacon 8 is to the installation position of the beacon 8. Therefore, the weight in the present embodiment includes the strength of the signal from the beacon 8 as a parameter.

Further, the smaller the distance between the first point and the second point, the narrower the range to be estimated as the installation position of the beacon 8, so that the weight in the present embodiment includes the reciprocal of the distance as a parameter. ..

Further, when the moving speeds of the plurality of terminals 6 are the same as each other, the moving distance becomes smaller as the time interval between the first time and the second time is smaller, so that the time interval is weighted in the present embodiment. Can be taken into account as a parameter of. However, in the present embodiment, the shorter time interval (also referred to as a short-time interval) of the first time interval and the second time interval (when corrected, the corrected second time interval) Include the reciprocal as a parameter in the weight. The reason is as follows. Of the first and second time intervals, for example, when the second time interval is small, the internal division point is closer to the second point. On the contrary, when the first time interval is smaller than the second time interval, the internal division point is closer to the first point. Assuming that each short-time interval of one or more terminals 6 having the same average moving speed is the second time interval, the internal division point estimated as the position at the reception time of each of these terminals 6 is as the short-time interval becomes smaller. Close to each second point. And again, the coordinates of the second point have been specified. On the other hand, the coordinates other than the first and second points are not specified in the movement path of the terminal 6. Therefore, among the linear interpolation coordinates of one or more terminals 6, it is better to give a large weight to the interpolation coordinates having a shorter short-time interval, because the range assumed as the installation position of the beacon 8 is narrowed and more accurate coordinates can be obtained. It is thought that it will be sought. Therefore, the reciprocal of the short interval is included in the weight as a parameter. However, it is not limited to this.

From these things, in this embodiment, the weight added to the linear interpolation coordinates is defined as follows.
Weight = (x × 1 / y × 1 / z)
Here, x, y, and z represent the strength of the signal from the beacon 8, the distance between the first point and the second point, and the short-time interval, respectively.

The position estimation device 2A according to the present embodiment does not make a correction in the case of passing. The reason is as follows. Since the average moving speed of the terminal 6 is high, the moving distance becomes large, which causes deterioration of the accuracy of position estimation. Here, in the above-mentioned weight, the reciprocal of the distance between the first point and the second point is used as a parameter, and the magnitude of the moving distance that causes the deterioration of accuracy has already been taken into consideration. Therefore, the position estimation device 2A according to the present embodiment does not perform the correction as in the case of staying in the case of passing. However, the present invention is not limited to this, and for example, correction may be performed for at least one of the first time interval and the second time interval.

Hereinafter, the operation of the position estimation device 2A according to the present embodiment will be described. FIG. 7 is a flowchart of processing by the position estimation device 2A according to the present embodiment. The data acquisition unit 20 of the position estimation device 2A acquires the reception information including the identifier of the beacon 8 to be the target of position estimation and the position time information including the ID included in the reception information from the movement history database 3 ( Step S100).

FIG. 8 is a diagram illustrating reception information and position / time information acquired by the data acquisition unit 20. In step S100, the data acquisition unit 20 acquires the received information and the position / time information as illustrated in FIG. 8 from the movement history database 3. The received information and the position / time information shown in FIG. 8 correspond to the received information and the position / time information shown in FIG. 2 in which specific numerical values are substituted.

From the received information shown in FIG. 8, it can be seen that the position estimation device 2A estimates the installation position of each beacon 8 of the identifiers p1 and p2. Further, from the reception information shown in FIG. 8, it can be seen that, for example, the terminal 6 of ID1 receives the signal of intensity 70 from the beacon 8 of the identifier p1 at time 0.

Further, from the position / time information shown in FIG. 8, it can be seen that, for example, the terminal 6 of ID1 acquires the information (10, 80) which is the coordinates of the sensor from the sensor 7 at time 0.

See FIG. 7 again. The locus extraction unit 21 generates locus extraction information using the reception information and the position / time information acquired by the data acquisition unit 20 (step S101).

FIG. 9 is a diagram illustrating the locus extraction information generated by the locus extraction unit 21. The locus extraction information shown in FIG. 9 is generated by the locus extraction unit 21 from the received information and the position / time information shown in FIG. Here, the information in which the received information and the position / time information are put together is divided for each ID of the terminal 6 and rearranged so that the times are in ascending order. As a result, the locus extraction information for each terminal 6 is generated. Further, in the locus extraction information for each terminal 6, data from the position time information immediately before and immediately after receiving the signal from the beacon 8 is used. Here, for example, referring to the locus extraction information of the terminal 6 of the ID 1, the terminal 6 is the coordinates of the installation position of the sensor 7 from the sensor 7 at time 0, as read from the received information described above (10, It can be seen that the information of 80) is acquired. Further, it can be seen that the terminal 6 receives a signal having an intensity of 70 from the beacon 8 having the identifier p1 at time 7. Further, it can be seen that the terminal 6 has acquired the information (0, 60) which is the coordinates of the sensor 7 from the sensor 7 at the time 60. Next, the processing by the position estimation unit 22 in step S102 will be described with reference to FIGS. 10 and 11.

FIG. 10 is a flowchart of processing by the position estimation unit 22 in the present embodiment. Further, FIG. 11 is a diagram illustrating the locus information generated based on the processing of the position estimation unit 22. The position estimation unit 22 calculates the first time interval, the second time interval, and the distance between the first point and the second point for each terminal 6 based on the locus extraction information. Further, the position estimation unit 22 calculates the time interval between the first point and the second point, divides the distance between the first point and the second point, and averages the terminals 6. Calculate the moving speed. When the average moving speed of the terminal 6 is higher than a predetermined value, the position estimation unit 22 determines that the terminal 6 is not stagnant. On the other hand, when the average moving speed of the terminal 6 is equal to or less than a predetermined value, the position estimation unit 22 determines that the terminal 6 is stagnant. Then, the position estimation unit 22 corrects the second time interval when the distance between the first point and the second point is a predetermined distance or more in the case of staying (step S200). In other cases, the correction is not performed (step S200).

In the present embodiment, the position estimation unit 22 calculates the average moving speed of the terminal 6 between the two points regardless of the distance between the first point and the second point. However, the present invention is not limited to this, and the position estimation unit 22 may not calculate the average moving speed between the two points when the distance is smaller than the predetermined distance.

With reference to FIG. 11, the processing of step S200 performed by the position estimation unit 22 will be specifically described. The unit of time in FIG. 11 is seconds. Further, it is assumed that the coordinates in FIG. 11 are coordinates on two coordinate axes parallel to the ground and orthogonal to each other, such as latitude and longitude, and the unit is meters. The unit of distance in FIG. 11 is meters. Further, the position estimation unit 22 according to the present embodiment is information that is an extension of the locus extraction information, and generates locus information including a value calculated by using the locus extraction information. However, the position estimation unit 22 may perform the processing of step S200, step S201, or step S203 by using the locus extraction information without generating the locus information.

Here, it is assumed that both the locus extraction information and the locus information are represented in a table format. However, the locus extraction information or the locus information does not have to be in a tabular format as long as the data in each column of the locus extraction information or the locus information is associated and stored for each ID. Further, the locus information does not have to have all the items in the column shown in FIG. 11, and may have some of these items. Alternatively, the locus information may have items other than the items in the column shown in FIG. It is assumed that the locus information and the locus extraction information in the present embodiment are temporarily stored in the position estimation device 2A. The stored locus information and the locus extraction information do not have to be stored as data that can be recognized by the user, and may be stored so that the position estimation device 2A can perform processing using the data. Further, the track information may be updated in the stored contents according to the processing by the position estimation device 2A. For example, when the position estimation device 2A no longer uses the information previously used in the locus information after a certain process, the information may be deleted and new information may be added to the locus information.

The case of ID1 will be described with reference to FIG. In the locus extraction information, the first time of the terminal 6 of ID1 is 0, the reception time is 7, and the second time is 60. Here, the position estimation unit 2A obtains the first time interval as 7 and the second time interval as 53. Here, these are recorded in a time interval column of locus information. Further, in the locus extraction information, the coordinates of the first point of the terminal 6 of ID1 are (10, 80), and the coordinates of the second point are (0, 60). From here, the position estimation unit 2A calculates the distance between the first point and the second point, and 22.36 (22.36 ≒ {(0-10) ² + (60-80) ² } ^{1 / 2} ) is obtained. Here, the value is recorded in the distance column of the locus information. Next, the position estimation unit 22 divides the distance between the first point and the second point by the sum of the first time interval and the second time interval, and the average movement of the terminal 6 of the ID 1 is performed. Calculate the speed. Here, the average moving speed is 0.37 (22.36 / 60≈0.37). Here, the average moving speed is recorded in the column of the average moving speed of the locus information.

Here, the condition for determining whether or not the terminal 6 is stagnant is whether or not the average moving speed is 1 or less. That is, when the average moving speed is 1 or less, it becomes a stagnation. Here, since the average moving speed of the terminal 6 of the ID 1 is 0.37, the position estimation unit 22 determines that the terminal 6 is stagnant.

Further, the position estimation unit 22 corrects the second time interval of the terminal 6 because the distance 22.36 between the first point and the second point of the terminal 6 of the ID 1 is smaller than the predetermined distance. Will not be done. Here, the predetermined distance related to the determination condition regarding the distance between the first point and the second point for correcting the second time interval is 25.

Similarly, the position estimation unit 22 calculates the distance between the first point and the second point for each ID. Further, the position estimation unit 22 calculates the average moving speed for each ID. Here, referring to the locus information for the terminal 6 of the ID 2 in FIG. 11, since the average moving speed is 0.37, which is equal to or less than a predetermined value, it can be seen that the terminal 6 of the ID 2 has a stagnation. Similarly, the distance between the first point and the second point in the terminal 6 of ID2 is 67.08, which is equal to or larger than a predetermined distance. From these, the position estimation unit 22 corrects the second time interval of the terminal 6 of ID2. The correction here is to multiply the second time interval by 1/10 and use the result obtained as a new second time interval. As a result, the second time interval of the terminal 6 of ID2, which was 150 before the correction, becomes 15. In the example shown in FIG. 11, the first time interval and the second time interval obtained after the correction process are shown in the column of correction time intervals.

See again FIG. The position estimation unit 22 calculates the internal division point on the line segment connecting the first point and the second point by using the ratio of the first time interval and the second time interval by linear interpolation. (Step S201). The second time interval used here will be the one after the correction if the above correction is made. Referring to FIG. 11, the linear interpolation coordinates in the case of ID1 not corrected in the second time interval are (8.8, 77.7), and the linear interpolation coordinates in the case of ID2 corrected in the second time interval are (8.8, 77.7). 30, 40).

Referring to FIG. 10, the position estimation unit 22 calculates the weight in the case of each ID following step S201 (step S202). As described above, the strength of the signal received from the beacon 8 by the terminal 6, the distance between the first point and the second point, and the short interval are used for the calculation of this weight.

The process of step S202 will be specifically described with reference to FIG. In the example shown in FIG. 11, the short-time interval and the distance between the first point and the second point for use in the weight calculation are the acquisition interval / time column and the acquisition interval for each ID, respectively. Recorded in the / distance column. Note that this "acquisition interval / time" indicates the time in the acquisition interval, and similarly, the "acquisition interval / distance" indicates the distance in the acquisition interval. In the case of ID1, since the first time interval is 7 and the second time interval is 53, the short time interval is 7. Further, in FIG. 11, since the distance between the first point and the second point in the case of ID1 is 22.36, 22.4 rounded off to the second decimal place of the value is the acquisition interval / distance. Shown in the column.

Similarly, in the case of ID2 in the locus information of FIG. 11, the second time interval 15 after correction, which is a short-time interval, is shown in the acquisition interval / time column, and 67 in the acquisition interval / distance column. .1 is shown.

The calculation of the weight by the position estimation unit 22 will be described with reference to FIG. The position estimation unit 22 substitutes each value of intensity, acquisition interval / distance, and acquisition interval / time for each of x, y, and z in the above-mentioned formula for calculating the weight for each ID, and assigns the weight. calculate. For example, in the case of ID1, the weight is 0.45 (0.45≈70 × 1 / 22.4 × 1/10). The same applies to the case of other IDs.

Referring to FIG. 10 again, the position estimation unit 22 uses the linear interpolation coordinates and the weights in each ID to estimate the coordinates of the position estimated as the installation position of the beacon 8 for each identifier of the beacon 8 (estimation of the beacon 8). (Also described as coordinates or estimated coordinates) is calculated (step S203). The position estimated as the installation position of the beacon 8 is also described as the estimated position. Similarly, the position of the terminal 6 in the linear interpolation coordinates is also described as the estimated position of the terminal. The position estimation unit 22 stores the estimated coordinates of the beacon 8 obtained in step S203 in the position information master database 4.

Referring to FIG. 11, the position estimation unit 22 calculates the weighted average by using the interpolated coordinates and the weights of IDs 1, 2 and 3 in the calculation of the estimated coordinates of the beacon 8 of the identifier p1. The estimated coordinates of the beacon 8 are obtained. In FIG. 11, the estimated coordinates are shown as (9.4, 63). The same applies to the calculation of the estimated coordinates of the beacon 8 of the identifier p2.

The position estimation device 2A may use the coordinates of the beacon 8 output to the position information master database 4 to estimate the position of another beacon 8 whose position is not specified. For example, in the position estimation device 2A, in estimating the position of a certain beacon 8, the beacon 8 includes the estimated position within a certain range from the installation position of the sensor 7 indicated by the position time information used at that time. Estimated coordinates of may be used. In this case, the terminal 6 that has received the signal from the beacon 8 whose position is to be estimated is estimated to be located in the vicinity of the sensor 7 together with the signal from the sensor 7 used for the estimation. It is highly possible that you are receiving a signal from. Therefore, the position estimation device 2A uses the information received from the beacon 8 from which such estimated coordinates are obtained as the position time information together with the estimated coordinates of the beacon 8 to position the other beacons 8. May be estimated. In this case, the data acquisition unit 20 acquires the estimated position of the beacon 8 from the position information master database 4. In this case, the data acquisition unit 20 or the locus extraction unit 21 generates position time information or locus extraction information from the estimated coordinates of the beacon 8 from the position information master database 4 and the received information related to the beacon 8. In order to determine whether the estimated coordinates of the beacon 8 recorded in the position information master database 4 are reliable, the coordinates do not change as a result of the position estimation of the beacon 8 more than a certain number of times. Information indicating that may be recorded in the database.

FIG. 12 is a diagram showing a comparative example of each accuracy when the position is estimated by using the conventional technique and when the position is estimated in the present embodiment. FIG. 12 shows the results of estimating the coordinates of the installation positions of the beacons 8 of the identifiers p1 and p2 using the locus extraction information shown in FIG. In FIG. 12, the case where the prior art that does not correct the second time interval is used is shown on the left, and the case where the position estimation method according to the present embodiment that corrects the second time interval is used is shown on the right. It is assumed that the prior art here includes the calculation of the interpolated coordinates of the terminal 6 by the linear interpolation and the calculation of the estimated coordinates of the beacon 8 by the weighted average of the interpolated coordinates. However, this assumption is for showing the effect when the correction of the second time interval is performed, and these are not always included in the actual prior art.

The estimated positions of each terminal 6 used for estimating the position of the beacon 8 are shown on the left and right of the upper part of FIG. The estimated position of the terminal 6 when the conventional technique is used corresponds to the internal division point obtained without correcting the time interval. In FIG. 12, as in the case of FIG. 3 and the like, the first point and the second point of each terminal 6 are represented by small circles, and the movement route related to the estimation of each terminal 6 is represented by a broken line. The IDn (n is a natural number) attached to each of these broken lines indicates the ID of the terminal 6 that is presumed to have moved along the movement path indicated by the broken line. Further, on the movement path, a mark indicating a signal (radio wave) from the beacon 8 and a mark whose outline is bordered by a broken line is written, and the point with this mark is the estimated position of the terminal 6. ..

In the left and right figures at the bottom of FIG. 12, the actual position and the estimated position of each beacon 8 are indicated by marks representing the solid line and the broken line beacon 8, respectively. Further, the solid line and the broken line ellipse drawn so as to surround the mark indicating the estimated position of the beacon 8 in the lower left and right figures of FIG. 12 indicate how far the installation position of the beacon 8 is from the estimated position of the beacon 8. It is described to indicate. Further, these ellipses indicate a range that can be further estimated as the installation position of the beacon 8 based on the estimated position of the beacon 8. Further, in the lower figure of FIG. 12, a number is described together with a mark whose outline is bordered by a wavy line, which represents a signal from Beacon 8, and this indicates a weight.

In FIG. 12, attention is paid to the beacon 8 having the identifier p2 and the terminals 6 having IDs 4, 5 and 6 used for estimating the position of the beacon 8. With reference to the upper left corner of FIG. 12, that is, the figure showing the estimated position of each terminal 6 obtained by using the prior art, the second time interval is not corrected. As shown in FIG. 11, terminals 6 of IDs 4, 5 and 6 all have stagnation. However, such retention is not reflected in the estimated position of each terminal 6 in the case of the prior art shown in the upper left of FIG. Therefore, the estimated position of the terminal 6 obtained by using the conventional technique may be significantly different from the position of the terminal 6 at the actual reception time. As described above, in the case of the prior art, an error may occur from the stage of obtaining the estimated position of the terminal 6 before calculating the estimated coordinates of the beacon 8. As a result, the range of estimation of the installation position of the beacon 8 is not narrowed. The estimated coordinates of the beacon 8 calculated from the coordinates of the estimated position of the terminal 6 obtained without taking the retention into consideration are likely to be different from the coordinates of the actual installation position of the beacon 8, and at the same time, the error is also present. It cannot be ignored. In the example shown in FIG. 12, the error (distance between the installation position of the beacon 8 and the estimated position) when this conventional technique is used is 13.7 m.

On the other hand, when the position estimation method according to the present embodiment is used, the fact that there is a stagnation in the terminals 6 of IDs 4, 5 and 6 is reflected in each of these interpolated coordinates. As a result, there is a high possibility that the estimated position at the reception time of the terminal 6 will be closer to the actual position. Further, as a result, the range in which the beacon 8 is expected to exist, which is shown by the broken line ellipse in each of the upper left and upper right views of FIG. 12, is narrower when the correction in the present embodiment is used than in the prior art. It is specified in the range. Then, it is considered that the error in the estimation of the installation position of the beacon 8 is reduced by performing the weighted average for the interpolated coordinates calculated by using this correction. As shown in the lower right of FIG. 12, when the position estimation method according to the present embodiment is used, the estimated position of the beacon 8 is closer to the actual installation position of the beacon 8 than in the conventional case. The error in this case was 6.1 m, which was smaller than that in the case of using the conventional technique.

According to the present embodiment, even when the movement of the terminal 6 before and after receiving the signal from the beacon 8 includes stagnation, it is possible to prevent deterioration of the accuracy of position estimation.

(Second embodiment)
In the first embodiment, the case where the identifier given to the beacon 8 to be the target of position estimation is uniquely determined for each beacon 8 has been described. However, there may be another Beacon 8 (also referred to as Spoofing Beacon 8F) that illegally has the same identifier as one Beacon 8. When the spoofing beacon 8F having a certain identifier is present as described above, the following problems may occur in estimating the installation position of the beacon 8 having the identifier (also referred to as the legitimate beacon 8T). In the estimation, the position estimation device 2A can acquire each received information from the terminal 6 that has received the signal from the legitimate beacon 8T and the terminal 6 that has received the signal from the spoofing beacon 8F. Then, the position estimation device 2A can acquire the position / time information including the IDs of these terminals 6. As a result, the position estimation device 2A may generate trajectory extraction information based on each received information regarding the legitimate beacon 8T and the spoofing beacon 8F. Then, the position estimation device 2A performs weighted averaging by combining the interpolated coordinates of each terminal 6 on the assumption that the terminal 6 that has received the signal from each of these beacons 8 has received the signal from the same beacon 8. there is a possibility. As a result of such a weighted average, the estimated position of the legitimate beacon 8T may shift from the actual installation position to the side of the installation position of the spoofing beacon 8F.

In the estimation of the installation position of the beacon 8 having a certain identifier, the position estimation device 2B according to the present embodiment determines that the estimated position of the beacon 8 is incorrect when there is another beacon 8 having the same identifier. It can be determined.

FIG. 13 is a diagram showing an example of the configuration of the position estimation system 1B according to the present embodiment. Since the elements other than the position estimation device 1B included in the position estimation system 1B in FIG. 13 are the same as those in the first embodiment, the description thereof will be omitted. However, the beacon 8 in FIG. 13 is a legitimate beacon 8T or a spoofing beacon 8F. Further, the position information master database 4 according to the present embodiment stores information on whether or not the estimated position of the beacon 8 is incorrect, in addition to the information stored in the case of the above embodiment. The connection relationship between the devices and the like included in the system is the same as the connection relationship in the above embodiment regardless of the code attached.

The position estimation device 2B includes an error determination unit 23 in addition to the above-mentioned functional block. The error determination unit 23 is connected to the position estimation unit 22 and acquires the estimated coordinates of the beacon 8 calculated by the position estimation unit 22 and the interpolated coordinates and weights of the terminal 6. The error determination unit 23 calculates the distance (also referred to as a difference distance) between the estimated position of the beacon 8 and the estimated position of the terminal 6, and calculates the error score using the distance and the weight. Here, the error score is defined as follows in this embodiment.
Error score = weight x difference distance

Explain the error score. Since this error score is calculated for each terminal 6, the error score calculated using the interpolated coordinates of a certain terminal 6 is also described as the error score of the terminal 6. When the weight given to the interpolated coordinates of the terminal 6 of a certain ID used for estimating the installation position of the beacon 8 having a certain identifier is large, the estimated position of the terminal 6 is usually the beacon 8. It is considered to be close to the installation position. However, when the difference distance is large despite the large weight, it is considered that the terminal 6 has received the signal from the spoofing beacon 8F having the same identifier as the beacon 8. Therefore, the error determination unit 23 has a function of determining that the estimated position of the beacon 8 is incorrect when the error score of the terminal 6 is larger than the threshold value in the estimation of the installation position of the beacon 8 of a certain identifier. ..

It should be noted that this threshold value is a value appropriately set by the user based on, for example, the average value of the distances of two beacons 8 out of any plurality of beacons 8 whose installation positions are specified.

Further, the error score is not limited to the above definition, and may be, for example, the sum of the weights having the same number of digits and the difference distance, or the smaller value of the weights having the number of digits combined with each other and the difference distance. But it may be.

The position estimation device 2B records the result determined by the error determination unit 23 in the position information master database 4 together with the estimated coordinates of the beacon 8 calculated by the position estimation unit 22.

FIG. 14 is a diagram for explaining the processing contents of each functional block of the position estimation device 2B according to the present embodiment. Here, since the processing by the data acquisition unit 20, the locus extraction unit 21, and the position estimation unit 22 and the information collected or derived by these are the same as in the case of the first embodiment, the description thereof will be omitted.

As described above, the error determination unit 23 acquires the estimated coordinates of the beacon 8 and the interpolated coordinates and the weight of the terminal 6, calculates an error score based on these, and determines whether or not the error score is larger than the threshold value. .. When the error score of at least one terminal 6 is larger than the threshold value in the estimation of the installation position of the beacon 8 having a certain identifier, the error determination unit 23 estimates that the beacon 8 is inaccurately calculated by the position estimation unit 22. Is determined to be. Further, the error determination unit 23 generates error determination information including the result of such determination. With reference to the error determination information shown in FIG. 14, it can be seen that the estimated coordinates of the beacon 8 of the identifier p1 are determined to have an error. Further, the determination result "-" in the case of the beacon 8 having the identifier p2 indicates that there is no error in estimating the position of the beacon 8. The data stored in the error determination information as the determination result that the estimation of the position of the beacon 8 is correct is not particularly limited as long as it is data indicating that there is no error, such as an initial value or a Kill value.

FIG. 15 is a flowchart of processing by the position estimation device 2B according to the present embodiment. In the flowchart, the main body and the processing contents of each processing from step S100 to step S102 are the same as those of the first embodiment described with reference to FIG. 7, and therefore the description thereof will be omitted. In step S103, processing by the error determination unit 23 of the position estimation device 2B is executed.

FIG. 16 is a flowchart of processing by the error determination unit 23 in the present embodiment. The error determination unit 23 is a difference distance which is a distance between the estimated position of the beacon 8 obtained by the position estimation unit 22 in step S102 and the estimated position of the terminal 6 used for estimating the installation position of the beacon 8. Is calculated (step S300). Subsequently, the error determination unit 23 calculates an error score using the difference distance calculated in step S300 and the weight calculated by the position estimation unit 22 in step S202 (FIG. 10) in step S102 (step S301). The error determination unit 23 compares the calculated error score with the threshold value. If the error score is larger than the threshold value, the error determination unit 23 determines that the estimated coordinates of the beacon 8 calculated in step S203 in step S102 are incorrect, and if not, the position of the beacon 8 is estimated. It is determined that there is no error (step S303). The error determination unit 23 stores the error determination result of the process in step S303 in the position information master database 4.

FIG. 17 is a diagram for explaining an example of error determination processing by the position estimation device 2B according to the present embodiment. Here, consider a case where the position estimation device 2B acquires the position / time information and the reception information shown on the left side of FIG. 17 from the movement history database 3. The position-time information here is the same as the position-time information exemplified in FIG. 8 for the purpose of explaining the processing by the position estimation device 2A according to the first embodiment. Further, the received information here is the same as the received information exemplified in FIG. 8 for the purpose of explaining the processing by the position estimation device 2A other than the identifier. In the received information in FIG. 17, the identifier included in the information related to the signal from the beacon 8 received by the terminal 6 of ID 1 to 6 is assumed to be p1.

The data acquisition unit 20 of the position estimation device 2B reads the position time information and the received information shown on the left side of FIG. 17 from the movement history database 3 by the process in step S100 (FIG. 7) in the first embodiment. In step S101, the locus extraction unit 21 generates locus extraction information from the position time information and the received information. The position estimation unit 22 derives a determination result of whether to perform correction by the process in step S200 (FIG. 10) described above. Further, the position estimation unit 22 appropriately corrects the second time interval of each terminal 6 in the above-mentioned step S201 based on the determination result. Then, the position estimation unit 22 uses the first and second time intervals after the correction when the correction is performed, and the original first and second time intervals when the correction is not performed, and the linearity of each terminal 6 is used. Calculate the interpolated coordinates. Further, in step S202, the position estimation unit 22 uses the distance between the first point and the second point, the short time interval, and the strength of the signal received from the beacon 8, and the linear interpolation coordinates of each terminal 6. Calculate the weight to be added to. Then, in step S203, the position estimation unit 22 calculates a weighted average of the linear interpolation coordinates of the terminals 6 of IDs 1 to 6 used for the beacon 8 of the identifier p1, and uses this as the estimated coordinates of the beacon 8.

In the case illustrated in FIG. 17, the estimated coordinates of the beacon 8 of the identifier p1 are calculated as (55.4, 39.6).

FIG. 18 is a diagram for explaining an example of error determination processing by the position estimation device 2B according to the present embodiment. The error determination unit 23 acquires the estimated coordinates (55.4, 39.6) of the beacon 8 of the identifier p1 and the linear interpolation coordinates of each terminal 6 of ID1 to ID6, and calculates the difference distance between them (). Step S300). In the example shown in FIG. 18, the value of the difference distance in the case of ID1 is 60.2, and the value of the difference distance in the case of ID2 is 25.4.

Using the calculated difference distance, the error determination unit 23 calculates an error score for each ID (step S301). In FIG. 18, the error score for ID1 is 26.9, and the error score for ID2 is 2.5.

Next, the error determination unit 23 determines whether or not the error score in each ID calculated in step S301 is larger than the threshold value. When at least one of the error scores in the case of the same identifier is larger than the threshold value, the error determination unit 23 determines that the estimated coordinates of the beacon 8 of the identifier calculated by the position estimation unit 22 are incorrect (step S302). ).

In the case of FIG. 18, when the threshold value is 7, the error score 26.9 in the case of ID1 is larger than the threshold value 7. From this, it can be seen that the estimated coordinates of the beacon 8 of the identifier p1 obtained by performing the weighted calculation using the linear interpolation coordinates of the terminal 6 of the ID 1 are highly likely to be incorrect. The error determination unit 23 generates error determination information as illustrated in the lower right of FIG. 18, and stores this in the position information master database 4.

FIG. 19 is a diagram showing an example of the effect of performing the error determination process in the present embodiment. Here, the result of performing the position estimation process and the error determination process based on the received information and the position time information shown in FIG. 17 is shown. The lines, circles, marks, and the like in FIG. 19 are the same as those described above.

The estimated position of each terminal 6 is shown in the upper left of FIG. Further, two beacons 8 having the same identifier p1 are shown here.

In the upper right corner of FIG. 19, the estimated position of the beacon 8 of the identifier p1 obtained by the weighted average is shown. The number beside the mark indicating the signal from the beacon 8 estimated to have been received by each terminal 6 at the estimated position represents the weight. For example, in the case of ID1, the weight is 0.45. Here, the weight in the case of ID1 is larger than the weight in the case of other IDs even though the estimated position of the terminal 6 of ID1 is far from the estimated position of the beacon 8. The weight should increase as it is closer to the beacon 8, which raises the question of whether the signal received by the terminal 6 of ID 1 is from the beacon 8 located at the estimated coordinates calculated by the position estimation unit 22.

Further, the error determination process will be described with reference to the lower diagram of FIG. Here, among the numbers beside the mark indicating the signal from the beacon 8, those outside [] represent weights, and those inside [] represent error scores. For example, in the case of ID1, the weight is 0.45 and the error score is 26.9. The error score in the case of ID1 is larger than the threshold value 25. Similarly, each error score in the case of IDs 5 and 6 is larger than the threshold value. Therefore, it can be recognized that the estimated position of the beacon 8 obtained by the position estimation unit 22 may be incorrect. As a result, the position estimation device 2B can prevent erroneous information from being accumulated in the position information master database 4 as correct information.

(Third embodiment)
The position estimation device 2B according to the second embodiment determines whether or not the position of the beacon 8 estimated by itself is correct in consideration of the case where two or more beacons 8 having the same identifier exist. be able to. However, even if the position estimation device 2B can determine that the estimated position of the beacon 8 is incorrect, it cannot estimate each installation position of two or more beacons 8 having the same identifier. The position estimation device 2C according to the present embodiment can estimate the installation position of each of two or more beacons 8 having the same identifier, in addition to being able to determine whether or not the estimated position of the beacon 8 is correct. ..

FIG. 20 is a diagram showing an example of the configuration of the position estimation system 1C according to the present embodiment. The position estimation system 1C includes a terminal 6, a sensor 7, a beacon 8, a movement history database 3, and an eta base 4 in the position information master according to the first and second embodiments described above. Since these are the same as in the above embodiment, the description thereof will be omitted. The beacon 8 is a legitimate beacon 8T or a spoofing beacon 8F. Further, the position estimation system 1C includes a position estimation device 2C. The connection relationship between the devices and the like included in the system is the same as the connection relationship in the above embodiment regardless of the code attached.

The position estimation device 2C includes a data acquisition unit 20, a trajectory extraction unit 21, and a position estimation unit 22, similar to the position estimation devices 2A and 2B in the above embodiment. In addition to these, the position estimation device 2C includes an error position estimation unit 24. Here, since the functional blocks other than the error position estimation unit 24 in the position estimation device 2C are the same as in the above embodiment, the description thereof will be omitted. However, although the position estimation unit 22 in the above embodiment is connected to the position information master database 4, the position estimation unit 22 in the present embodiment does not have to be connected to the position information master database 4. The error position estimation unit 24 is connected to the position estimation unit 22 and the position information master database 4.

The error position estimation unit 24 acquires the estimated coordinates of the beacon 8, the interpolated coordinates of the terminal 6, and the weights for each interpolated coordinate calculated by the position estimation unit 22. Then, the error position estimation unit 24 calculates each estimated coordinate of the plurality of beacons 8 having the same identifier as described later based on these. The error position estimation unit 24 is connected to the position information master database 4 and outputs the calculated estimated coordinates of the beacon 8 to the position information master database 4.

FIG. 21 is a diagram for explaining the processing contents of each functional block of the position estimation device 2C according to the present embodiment. Here, each process by the data acquisition unit 20, the locus extraction unit 21, and the position estimation unit 22 and the information collected or derived by these functional blocks are the same as in the first and second embodiments. The explanation is omitted.

The error position estimation unit 24 acquires the weights given to the estimated positions of the beacon 8 and the terminal 6 and the interpolated coordinates of the terminal 6 calculated by the position estimation unit 22. The error position estimation unit 24 uses these acquired information to calculate the estimated coordinates of each of the beacons 8 having the same identifier when there are a plurality of beacons 8 having the same identifier. At the lower right of FIG. 21, the estimated coordinates of the beacon 8 calculated by the error position estimation unit 24 are shown. It can be seen that there are two beacons 8 with the identifier p1, and each of these estimated coordinates is X'1-1 and X'1-2.

FIG. 22 is a flowchart of processing by the position estimation device 2C according to the present embodiment. Here, since the processes from step S100 to step S102 are the same as those in the above embodiment, the description thereof will be omitted. However, in step S102, the position estimation unit 22 in the above embodiment outputs the estimated coordinates of the beacon 8 to the position information master database 4, but the position estimation unit 22 according to the present embodiment outputs the estimated coordinates to the position information master database 4. There is no such output. However, the present invention is not limited to this, and the estimated coordinates of the beacon 8 may be output from the position estimation unit 22 to the position information master database 4. In this case, after the output by the position estimation unit 22, the error position estimation unit 24 outputs the estimated coordinates of the beacon 8 to the position information master database 4, and the position information master database 4 updates the estimated coordinates of the beacon 8 based on this. You may. Alternatively, when the error score of the terminal 6 used for estimating the position of the beacon 8 of a certain identifier is larger than the threshold value, the error position estimation unit 24 uses the calculated estimated coordinates of the beacon 8 of the identifier as the position information master. It may be output to the database 4.

FIG. 23 is a flowchart of the process (step S104 in FIG. 22) by the error position estimation unit 24 in the present embodiment. Further, FIGS. 24, 25, 26, and 27 are diagrams showing an example of the error position estimation process in the present embodiment. Hereinafter, the error position estimation process will be described with reference to FIGS. 23 and 24 to 27. Note that FIGS. 24 to 27 are related to the error position estimation process when the position estimation device 2C reads the position / time information and the received information shown on the left side of FIG. 21.

The error position estimation unit 24 calculates the difference distance from the estimated coordinates of the beacon 8 and the terminal 6 calculated by the position estimation unit 22 using the locus information (step S400). With reference to FIG. 24, it can be seen that, for example, the difference distance in the case of ID1 is determined to be 60.2, and the difference distance in the case of ID2 is determined to be 25.4.

Return to FIG. Following step S400, the error position estimation unit 24 calculates an error score (step S401). With reference to FIG. 24, it can be seen that the error position estimation unit 24 calculates the error score for ID1 to be 26.9 and the error score for ID2 to be 2.5.

Return to FIG. Following step S401, the error position estimation unit 24 determines whether the error score of each terminal 6 is larger than the threshold value (step S402).

Referring to FIG. 24, in the case of ID1, the error score is 26.9, which is larger than the threshold value of 7. Therefore, the error position estimation unit 24 assumes that the signal received by the terminal 6 of ID1 is from the beacon 8 presumed to be installed at the position corresponding to the coordinates (55.4, 39.5). Determines that it may be incorrect. As a result, in the locus information exemplified in FIG. 24, the determination result in the case of ID1 is "error". Similarly, in the case of ID2, the error score is 2.5, which is smaller than the threshold value of 7. Therefore, it is determined that the signal received by the terminal 6 of the ID 2 is likely to be from the beacon 8 presumed to be at the position corresponding to the coordinates (55.4, 39.5). Therefore, in the locus information exemplified in FIG. 24, the determination result in the case of ID2 is indicated by "-".

Return to FIG. Following step S402, the error position estimation unit 24 of the terminal 6 having the highest error score when there is a terminal 6 having an error score larger than the threshold value for the beacon 8 of a certain identifier (step S403: Yes). The estimated position (interpolated coordinates) is classified into another cluster (step S404). Subsequently, the error position estimation unit 24 calculates the weighted average of the interpolated coordinates of the terminal 6 for each cluster. The position corresponding to the coordinates obtained by the calculation is also described as the center of gravity. The error position estimation unit 24 calculates the distance between the estimated position of each terminal 6 and the center of gravity of each cluster (the distance is also described as the difference distance). Then, the error position estimation unit 24 reclassifies the estimated position of the terminal 6 into the cluster having the smallest difference distance between the estimated position of the terminal 6 and the center of gravity (step S406). The error position estimation unit 24 determines whether or not the classification destination of the estimated position of each terminal 6 has changed before and after step S406, and if it has changed (step S407: Yes), the process returns to the process of step S405. .. On the other hand, if the classification destination of the interpolated coordinates of each terminal 6 has not changed before and after step S406 (step S407: No), the error position estimation unit 24 returns to the process of step S400. The error position estimation unit 24 may return to the process of step S401 instead of returning to the process of step S400.

The process of step S404 will be described with reference to FIG. 25. FIG. 25 shows a process following the process specifically exemplified in FIG. 24. Referring to the determination result of the locus information shown above in FIG. 25, there is an “error” (step S403: Yes). As a result, the error position estimation unit 24 classifies the interpolated coordinates (8.8, 77.7) of the terminal 6 of ID1 having the highest error score of 26.9 into another cluster (step S404). In the case of FIG. 25, the cluster name corresponds to the identifier of the beacon 8, but the cluster in which the interpolation coordinates (8.8, 77.7) are classified is p1-2, and other interpolation coordinates are included. The cluster is p1-1. Next, the error position estimation unit 24 calculates the weighted average of the interpolated coordinates in each of the clusters p1-1 and p1-2, and the coordinates of the center of gravity of the cluster p1-1 (76.1, 22.5) and the cluster. The coordinates (8.8, 77.7) of the center of gravity of p1-2 are obtained (step S405).

In FIG. 25, the error position estimation unit 24 further calculates the difference distance between the estimated position of the terminal 6 corresponding to each linear interpolation coordinate and the center of gravity of each cluster, and the estimated position of each terminal 6 is calculated by the difference distance. Reclassify into smaller clusters. The locus information shown in the lower part of FIG. 25 shows the difference distance between the estimated position of each terminal 6 and each center of gravity. For example, the estimated position of the terminal 6 corresponding to the interpolated coordinates (30, 40) and the cluster. The difference distance from the center of gravity of p1-1 is 49.3. The distance between the estimated position of the terminal 6 and the center of gravity of the cluster p1-2 is 43.2. From this, it can be seen that the estimated position of the terminal 6 is closer to the center of gravity of the cluster p1-2 than the center of gravity of the cluster p1-1. Therefore, the error position estimation unit 24 reclassifies the estimated position of the terminal 6 into the cluster p1-2 (step S406). With reference to the clusters to which the interpolated coordinates (30, 40) are classified in the locus information in the upper and lower stages of FIG. 25, they are classified into clusters p1-1 and clusters p1-2 before and after step S405, respectively, and are classified into the classification results. It can be seen that the change has occurred (step S407).

FIG. 26 shows a continuation of the processing by the error position estimation unit 24 shown in FIG. 25, in which the error position estimation unit 24 when the processing shifts from the processing in step S407 to step S405 (step S407: Yes in FIG. 23). The content of the processing by is shown. The error position estimation unit 24 recalculates the weighted average of each interpolated coordinate in each of the clusters p1-1 and p1-2 using the trajectory information after reclassification shown in the upper part of FIG. 26 (step S405). .. As a result, the coordinates of the centers of gravity of the clusters p1-1 and p1-2 become (81.2, 20.6) and (12.7, 70.8) as shown in the middle of FIG. 26. The error position estimation unit 24 recalculates the distance between the estimated position of the terminal 6 corresponding to each interpolated coordinate and each center of gravity. As a result, for example, the difference distance between the estimated position of the terminal 6 corresponding to the interpolated coordinates (30, 40) and the center of gravity of the cluster p1-1 is 54.8, and the estimated position of the terminal 6 and the cluster p1-2. The difference distance from the center of gravity is 35.4. The error position estimation unit 24 reclassifies each interpolated coordinate into clusters in which the difference distance from the center of gravity is small. In the lower part of FIG. 26, the locus information storing the result when the classification is performed again for each interpolated coordinate is shown. Here, it can be seen that there is no change in the classification result of the interpolated coordinates after the processing of the immediately preceding step S405 (step S407: No in FIG. 23). As a result, the error position estimation unit 24 returns the process to step S400.

FIG. 27 shows a continuation of the processing by the error position estimation unit 24 shown in FIG. 26. The error position estimation unit 24 uses the coordinates of the center of gravity of each cluster shown in the middle of FIG. 27, and the difference distance between the estimated position of the terminal 6 and the center of gravity of the cluster in which the interpolated coordinates of the terminal 6 are classified. Is calculated (step S400). Instead of calculating the difference distance in step S400, the error position estimation unit 24 may use the shorter difference distance calculated in step S406, thereby updating the difference distance in the locus information. At this time, the error position estimation unit 24 may delete the longer difference distance calculated in step S406. For example, in the case of ID1 in the locus information shown in the upper part of FIG. 27, the difference distance 7.9 is shown.

The error position estimation unit 24 calculates an error score from the difference distance and the weight in each ID obtained in the process of the immediately preceding step S400 (step S401). In FIG. 27, it can be seen that in the case of ID1, the error score is 3.5. The error score is less than the threshold value of 7. Similarly, it can be seen that the error score is below the threshold value in each of the cases of IDs 2, 3, 4, 5, and 6. As a result, the error position determination unit 24 determines that there is no error score larger than the threshold value (step S403: No). At this time, the coordinates (81.2, 20.6) and (12.7, 70.8) of the center of gravity of each cluster calculated in the immediately preceding step S405 are used as the estimated coordinates of the two beacons 8 having the identifier p1. You can see it. This eliminates the contradiction that the beacon 8, which is said to have emitted the signal received by the terminal 6, exists far away even though the weight is large.

Further, here, in step S404, the interpolated coordinates of one terminal 6 having the highest error score is different from the case where each estimated position of two or more terminals 6 having an error score larger than the threshold value is collectively classified into another cluster. It is classified into a cluster of. The reason for this is that even if the estimated positions of the two or more terminals 6 are collectively classified into another cluster, these terminals 6 do not always receive the signal from the same beacon 8. Then, in step S404, one interpolated coordinate is classified into another cluster for each process of step S403, and by performing the subsequent processing, a situation in which an error score exceeding the threshold value is generated is collected, and each interpolated coordinate is collected. Will be grouped into clusters to be categorized.

When there is no error score larger than the threshold value (step S403: No), the error position estimation unit 24 outputs the calculated estimated position of the beacon 6 to the position information master database 4 and ends the process. Along with this, the position estimation device 2C ends a series of processes as shown in FIG. 22.

FIG. 28 is a diagram showing an example of the effect obtained in the position estimation by the position estimation device 2C according to the present embodiment. The weights and error scores of each terminal 6 shown in the left figure of FIG. 28, the estimated movement route, the estimated position of the beacon, and the like are the same as those of FIG. 19 and the like. Further, the process exemplified in FIG. 28 shows a case where the error position estimation unit 24 performs the process using the locus information in FIGS. 24 to 27. The figure shown on the left of FIG. 28 shows a state in which the error score of each terminal 6 is first calculated after the error position estimation unit 24 starts processing. In the case of ID1, the error score is 26.9, which is larger than the threshold value 7 and is the highest value among the error scores from ID1 to ID6. As a result, as shown in the middle of FIG. 28, the estimated position in the case of ID1 is divided into clusters different from the estimated position of the terminal 6 of another ID. Considering the center of gravity of each cluster as the estimated position of the beacon 8 at this point, the estimated position of the beacon 8 in the cluster p1-2 in the middle figure of FIG. 28 is equal to the estimated position of the terminal 6 of ID1. The estimated position of the beacon 8 in the cluster p1-1 is the position indicated by the figure showing the estimated position of the other beacon 8 in the middle figure of FIG. 28. In this case, when the error score is calculated, it becomes the number in [] in the middle figure of FIG. 28. For example, the error score in the case of ID2 of linear coordinates (30, 40) is the difference distance 49.3 between the center of gravity of cluster p1-1 and the estimated position of terminal 6 of ID2 from the locus information shown in the lower part of FIG. And 4.9, which is the product of the weight 0.1.

The error position estimation unit 24 further classifies the estimated position of the terminal 6 of each ID so that the distance from the center of gravity becomes smaller. The center of gravity of each cluster calculated based on the classification is indicated by the mark of the estimated position of the beacon 8 in the right figure of FIG. 28. Further, the error score of each terminal 6 is shown in [] in this figure, and it can be seen that the error scores are all below the threshold value. From this, it can be seen that the position of the center of gravity of each cluster corresponds to the estimated position of each of the two beacons 8 having the same identifier.

As described above, according to the position estimation device 2C according to the present embodiment, even when two or more beacons 8 having the same identifier exist, the position of each of these beacons 8 is estimated without deteriorating the accuracy. Can be done.

(Other Embodiment 1)
The position estimation devices 2A, 2B, and 2C according to the above embodiment estimated the position of the beacon 8 based on the reception information and the position time information from the terminal 6 that received the signal from the beacon 8 and the sensor 7. The position estimation device 2D according to the present embodiment uses data in SNS (social networking service) or the like including a word as a keyword instead of the received information based on the signal from the beacon 8. Here, the keyword word is, for example, a cooking name such as "ramen" or "pasta", or a product name such as "suit" or "shoes". The data including such a word is referred to as SNS data here.

FIG. 29 is a diagram showing a position estimation method according to another embodiment. Here, the position estimation device 2D reads the SNS data from the cloud or the like instead of the reception information described above. The SNS data shown in FIG. 29 includes the ID of the terminal 6 used for inputting the word included in the SNS data, the time when the word was written on the SNS homepage, the character data of the word, and the character data of the word. Includes the reliability of the input content. The reliability of the input content is a numerical value indicating how reliable the content written from the terminal 6 is. The reliability can be changed depending on the terminal 6 and the written contents. The reliability corresponds to the strength of the signal from the beacon 8 in the above embodiment, and therefore, the reliability is also referred to as the strength below.

In the above embodiment, the time when the terminal 6 receives the signal from the transmitter such as the beacon 8 is set as the reception time, but here, the time when the word is written on the SNS homepage or the person who wrote the writing is written. The time when the information that triggered the operation was acquired corresponds to this. Therefore, these times are collectively referred to as the reception time.

Further, the signal from the beacon 8 in the above embodiment corresponds to the store information or the like found by the person who wrote to the SNS while moving. Further, in the present embodiment, the store or the like corresponds to the beacon 8 or the like in the above embodiment.

With reference to the SNS data shown in FIG. 29, it can be seen that the word "ramen" is written on the SNS homepage at times 7, 30 and 40 from the terminals 6 of IDs 1, 2 and 3, respectively. Further, it can be seen that the reliability of the writing from the terminals 6 of IDs 1, 2 and 3 is 70, 100 and 90, respectively. The position estimation device 2D estimates the location of, for example, a ramen shop using these SNS data and the position / time information.

First, the position estimation device 2D is information corresponding to the above-mentioned trajectory extraction information, and generates information in which the position time information and the SNS data are collected for each ID and arranged in ascending order of time. At this time, the position estimation device 2D combines the position-time information related to the time immediately before and after the time of the SNS data with the SNS data. The information thus generated also describes the locus extraction information.

Similar to the above embodiment, the position estimation device 2D has the movement path of the terminal 6 of each ID and the estimated position of the terminal 6 at the reception time, that is, the position (writing) at which the word is estimated to be written on the homepage of the SNS. (Also referred to as the estimated position) is derived. The figure shown to the left of the center of the upper part of FIG. 29 shows the movement route of each of the derived terminals 6 and the estimated writing position of each terminal 6. Here, it is presumed that "ramen" was written on the SNS homepage at the point of the cloud mark without hatching, and "pasta" is at the point of the cloud mark with hatching on the SNS homepage. Presumed to have been written above.

The position estimation device 2D calculates a weighted average for each word for these write estimation positions, and estimates the position of a store or the like related to the word. The weights in this embodiment are defined as in the case of the above embodiment. The word here corresponds to the identifier of Beacon 8 in the above embodiment.

A specific example of the estimation result is shown in the upper right of FIG. 29. Here, (14.1, 68.7) is obtained as the coordinates of the estimated position of the ramen shop.

FIG. 30 is a diagram showing a functional block of the position estimation device 2D according to the present embodiment. Each functional block of the position estimation device 2D according to the present embodiment is the same as the functional block of the position estimation device 2A according to the first embodiment. However, the data acquisition unit 20 in the present embodiment is connected to a cloud or the like, or is directly connected to the network 5, in addition to the movement history database 3 and the location information master database 4.

Further, the position estimation unit 22 may be connected to a cloud or the like or directly connected to the network 5 in addition to the position information master database 4. Alternatively, the location information master database 4 may be connected to the network 5, and may be, for example, a database in the cloud.

The process related to the position estimation by the position estimation device 2D according to the present embodiment is the same as that shown in FIGS. 7 and 10. However, the data acquisition unit 20 acquires SNS data instead of the received information in step S100. Further, instead of the process of step S203 in FIG. 10, the position estimation unit 20 estimates the position of the store or the like that provides the thing or the like that the word means, and calculates the coordinates thereof. Further, in step S203, the position estimation unit 22 may store the estimated position of the store or the like in the cloud or the like instead of the position information master database 4.

According to the position estimation device 2D according to the present embodiment, the user of the terminal 6 sees the provided item or the like from the store or the like while moving, and writes the data written on the SNS homepage in the place where the provided item or the like is handled. It can be effectively used to estimate the location of the store or the like. As a result, it is possible to provide the user having the terminal 6 connected to the network 5 with information on the location of the target store and where to obtain the target product.

(Other Embodiment 2)
In the other embodiment 1 described above, there are the following problems when there are a plurality of stores or the like that provide the same product or the like. As a result of similar words being written on the SNS homepage by each user of one or more terminals 6 passing in front of multiple stores, etc., the SNS data that should be related to multiple stores, etc. is related to one store, etc. Can be treated as. Then, the estimated coordinates of the store or the like calculated by the position estimation device 2D using such SNS data may be different from the actual position.

The position estimation device 2E according to the present embodiment estimates the position of each of a plurality of stores or the like that provide the same product or the like.

The position estimation device 2E according to the present embodiment acquires position time information and SNS data acquired by the position estimation device 2D according to the other embodiment 1 described above. Then, the position estimation device 2E creates locus extraction information based on these, and estimates the position of the store or the like in the same manner as in the above embodiment. At this time, the second from the distance (the distance is also described as the difference distance) between the estimated position at the reception time of the terminal 6 used for estimating the position of the store or the like and the estimated position of the store or the like, and the weight. The same error score as in the case of the third embodiment is calculated. Then, as in the third embodiment, the positions of a plurality of stores and the like associated with the same word are estimated.

FIG. 31 is a diagram showing a functional block of the position estimation device 2E according to the present embodiment. Each functional block of the position estimation device 2E according to the present embodiment is the same as the functional block of the position estimation device 2C according to the third embodiment. However, the data acquisition unit 20 in the present embodiment may be connected to a cloud or the like or directly connected to the network 4 in addition to the movement history database 3 and the location information master database 4.

Further, the error position estimation unit 24 in the present embodiment may be connected to a cloud or the like or directly connected to the network 5 in addition to the position information master database 4. Alternatively, the location information master database 4 may be connected to the network 5, and may be, for example, a database in the cloud.

The process related to the position estimation by the position estimation device 2E according to the present embodiment is the same as that shown in FIGS. 22 and 23. However, the data acquisition unit 20 in the present embodiment acquires SNS data instead of the received information in step S100. Further, the position estimation unit 22 in the present embodiment calculates the coordinates of the estimated position of the store or the like that provides the thing that the word means, etc., instead of obtaining the coordinates of the estimated position of the beacon 8 instead of the processing of step S102. do. In the process in step S104 by the error position estimation unit 24 in the present embodiment, instead of the coordinates of the estimated position of the beacon 8 calculated in the above embodiment, the coordinates of each estimated position of a plurality of stores and the like associated with the same word are used. calculate. Further, when there is no error score larger than the threshold value in step S403, the error position estimation unit 24 in the present embodiment transfers the estimated position of the store or the like to the position information master database 4 or the cloud or the like instead of the coordinates of the estimated position of the beacon 8. Remember.

FIG. 32 is a diagram showing an example of processing by the position estimation device 2E according to the present embodiment. The position estimation device 2E acquires the position / time information and SNS data shown on the left side of FIG. 32. This position / time information is the same as that in the above embodiment. Further, the SNS data is the same as the SNS data in the above embodiment except for the words, and all the words are "ramen".

The figure on the left side from the center of the upper row in FIG. 32 is the same as in the case of the other embodiment 1. The upper right figure of FIG. 32 shows the estimated positions of the plurality of ramen shops derived by the error position estimation unit 24. Here, it can be seen that there are two ramen shops that triggered the writing of the word "ramen" on the SNS homepage. It can be seen that (82.2, 20.6) was calculated as the estimated coordinates of one of these ramen shops, and (12.7, 70.8) was calculated as the estimated coordinates of the other.

According to the position estimation device 2E according to the present embodiment, even if there are a plurality of stores offering the same product or the like, the position of each of the plurality of stores is estimated using a short word in the SNS data. be able to.

(Other Embodiment 3)
In the above embodiment, the positions of the fixed beacon 8 and the store are estimated based on the received information from the moving terminal 6. However, the position estimation device 2A or the like may estimate the position of the mobile terminal instead of the fixed beacon 8 by using a receiver such as a fixed gateway instead of the terminal 6. In this case, the fixed receiver such as a gateway corresponds to the terminal 6 in the above embodiment, and the mobile terminal corresponds to the transmitter such as the beacon 8 in the above embodiment. The sensor 7 used at this time may or may not be fixed as long as the position is specified.

(Other Embodiment 4)
In the above embodiment, the average moving speed of the terminal 6 is calculated, and it is determined whether or not the terminal 6 has a stagnation. However, if the sensor 7 or the beacon 8 can acquire information such as the relative speed and the relative direction with the terminal 6, the terminal 6 acquires such information from the sensor 7 or the beacon 8. May be good. Then, the position estimation device 2A or the like that has acquired information such as the relative speed from the terminal 6 may use this for estimating the position of the beacon 8.

FIG. 33 is a diagram showing an example of a hardware configuration for realizing each function of each position estimation device according to the first, second, and third embodiments and the other embodiments 1, 2, 3, and 4. Here, each position estimation device has hardware as a general computer, and the processing by each position estimation device is executed by specifically using the hardware 9 shown below. The hardware 9 includes a processor 91, a memory 92, a storage device 93, a network interface circuit 94, and an input device 95 connected to each other by a bus 90.

The processor 91 is, for example, a single-core, dual-core, or multi-core processor.

The memory 92 is, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or a semiconductor memory.

The processor 91 executes various programs stored in the memory 92 by using the information stored in the memory 92 or the information read from the storage device 93 into the memory 92, whereby the locus extraction unit 21 and the position estimation unit 22 are executed. Function is realized. Similarly, the processor 91 and the memory 92, or the processor 91 and the memory 92 and the storage device 93 realize the functions of the error determination unit 23 in the second embodiment and the like, and the error position estimation unit 24 in the third embodiment and the like. Can be.

The storage device 93 is, for example, a hard disk drive, an optical disk device, or the like, and may be an external storage device or a portable storage medium. The movement history database 3 and the location information master database 4 may be realized by the storage device 93.

The network interface circuit 84 is an interface for allowing the position estimation device to communicate with other nodes via a LAN (Local Area Network), the Internet, an intranet, or the like. When the movement history database 3 or the position information master database 4 exists outside the position estimation device, or when the position estimation device collects information from the cloud or the like, the data acquisition unit 20 collects data by the network interface circuit 23. The function is realized. Further, when the data acquisition unit 20 selects the beacon 8 for which the position is estimated, the function of the data acquisition unit 20 is realized by the processor 91, the memory 92, and the like.

The input device 95 is, for example, a keyboard, a touch panel, or the like, and is for the user to select a beacon 8 whose position is to be estimated and to input an identifier or the like of the beacon 8. In addition, when the beacon 8 to be the target of position estimation is automatically eliminated by the position estimation device, the input device 95 may be omitted.

In addition to the above cases, the functions of all or a part of the functional blocks of FIGS. 1, 13, 20, 30, and 31 can be appropriately realized by dedicated hardware.

Further, the following appendices will be disclosed with respect to the embodiments including the above-described embodiments 1 to n.
(Appendix 1)
The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. An acquisition unit for acquiring position-time information and second position-time information acquired at a second point by the terminal at a second time after the reception time.
The average movement speed between the first point and the second point of the terminal is calculated from the first position time information and the second position time information, and the average movement speed is equal to or less than a predetermined value. When the distance between the first point and the second point is equal to or greater than a predetermined distance, the first time interval between the first time and the reception time and the said. A correction is made to at least one of the second time intervals between the reception time and the second time, and the correction is made to at least one of the first time interval and the second time interval after the correction. Based on this, a position estimation unit that estimates the position of the terminal at the reception time and estimates the position of the transmitter based on the estimation.
A position estimation device characterized by comprising.
(Appendix 2)
The position estimation device according to Appendix 1, wherein the position estimation unit performs the correction with respect to the second time interval.
(Appendix 3)
The position estimation unit is
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is less than the predetermined distance, the correction is performed, and the first after the correction is performed. The position of the terminal (6) at the reception time is estimated based on at least one of the time interval and the second time interval.
The position estimation device according to Appendix 1 or 2, characterized in that.
(Appendix 4)
The position estimation unit is
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is less than the predetermined distance, the correction is not performed and the first time is not performed. The position of the terminal at the reception time is estimated based on at least one of the interval and the second time interval.
The position estimation device according to Appendix 1 or 2, characterized in that.
(Appendix 5)
The position estimation unit is
When the correction is performed, the position of the terminal at the reception time is estimated by performing linear interpolation using at least one of the first time and the second time after the correction.
When the correction is not performed, the position of the terminal at the reception time is estimated by performing linear interpolation using at least one of the first time and the second time.
The position estimation device according to any one of Supplementary Provisions 1 to 4, wherein the position estimation device is characterized by the above.
(Appendix 6)
The position estimation unit is
When making the correction, the position of the terminal at the reception time is estimated based on the shorter time interval of the first time interval and the second time interval after the correction.
When the correction is not performed, the position of the terminal at the reception time is estimated based on the shorter time interval of the first time interval and the second time interval.
The position estimation device according to any one of Supplementary Provisions 1 to 5, characterized in that.
(Appendix 7)
The position estimation unit is
The coordinates of the position of the transmitter are calculated by weighting the estimated coordinates of the position of the terminal.
The weight is
When the correction is performed by the position estimation unit, it is calculated using at least one of the first time interval and the second time interval after the correction.
If the correction is not performed by the position estimation unit, it is calculated using at least one of the first time interval and the second time interval.
The position estimation device according to any one of Supplementary Provisions 1 to 6, characterized in that.
(Appendix 8)
The position according to Appendix 7, wherein at least one of the strength of the signal and the distance between the first point and the second point is used for the calculation of the weight. Estimator.
(Appendix 9)
The position estimation device further
The difference distance between the estimated position of the transmitter and the estimated position of the terminal used for estimating the position of the transmitter is calculated.
An error determination unit that calculates an error score based on the difference distance and the weight, and determines that the signal is not transmitted from the transmitter when the error score is larger than the threshold value.
The position estimation device according to Supplementary Note 7 or 8, wherein the position estimation device is provided.
(Appendix 10)
The position estimation device further includes an error position estimation unit.
The error position estimation unit is
The difference distance between the estimated position of the transmitter and each estimated position of one or more terminals used for estimating the position of the transmitter is calculated.
For each terminal, an error score is calculated based on the difference distance and the weight.
When at least one of the error scores of the one or more terminals is larger than the threshold value, the signal received by the terminal having the highest error score of the one or more terminals is the transmitter. Judging that it was transmitted from a different transmitter,
Of the one or more terminals, the estimated position of the transmitter is derived again based on the estimated position of the terminal determined to have received the signal transmitted from the transmitter.
Of the one or more terminals, the estimated position of the other transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the other transmitter.
The position estimation device according to Appendix 7 or 8, characterized in that.
(Appendix 11)
The error position estimation unit is
The difference distance between each estimated position of the one or more terminals and the estimated position of the transmitter is calculated.
The difference distance between each estimated position of the one or more terminals and the estimated position of the other transmitter is calculated.
When the difference distance between the estimated position of the terminal and the estimated position of the transmitter is equal to or less than the difference distance between the estimated position of the terminal and the estimated position of the other transmitter, the terminal receives the reception time. It is determined that the signal has been received from the transmitter in
When the difference distance between the estimated position of the terminal and the estimated position of the transmitter is larger than the difference distance between the estimated position of the terminal and the estimated position of the other transmitter, the terminal has the reception time. Determined that a signal was received from the other transmitter in
Of the one or more terminals, the estimated position of the transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the transmitter.
Of the one or more terminals, the estimated position of the other transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the other transmitter.
The position estimation device according to Appendix 10, wherein the position is estimated.
(Appendix 12)
The error position estimation unit is
The terminal determined to have received the signal transmitted from the transmitter is classified into the first cluster, and the terminal determined to have received the signal transmitted from the other transmitter is classified into the second cluster. Classify into
The estimated position of the transmitter is derived based on the estimated position of the terminal in the first cluster.
Deriving the estimated position of the other transmitter based on the estimated position of the terminal in the second cluster.
The position estimation device according to Appendix 10 or 11, characterized in that.
(Appendix 13)
The position estimation device according to any one of Supplementary note 1 to 12, wherein the transmitter is a beacon.
(Appendix 14)
The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. The position-time information and the second position-time information acquired at the second point at the second time after the reception time by the terminal are acquired.
From the first position / time information and the second position / time information, the average moving speed between the first point and the second point of the terminal is calculated.
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is equal to or more than a predetermined distance, the time between the first time and the reception time is reached. The first time interval and at least one of the second time intervals between the reception time and the second time are corrected, and the first time interval and the second time interval after the correction are corrected. The position of the terminal at the reception time is estimated based on at least one of the time intervals of the above, and the position of the transmitter is estimated based on the estimation.
A position estimation program that causes a position estimation device to execute processing.
(Appendix 15)
The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. The position-time information and the second position-time information acquired at the second point at the second time after the reception time by the terminal are acquired.
From the first position / time information and the second position / time information, the average moving speed between the first point and the second point of the terminal is calculated.
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is equal to or more than a predetermined distance, the time between the first time and the reception time is reached. The first time interval and at least one of the second time intervals between the reception time and the second time are corrected, and the first time interval and the second time interval after the correction are corrected. The position of the terminal at the reception time is estimated based on at least one of the time intervals of the above, and the position of the transmitter is estimated based on the estimation.
A position estimation method performed by a position estimation device.

1 Position estimation system 2A, 2B, 2C, 2D, 2E Position estimation device 3 Movement history database 4 Position information master database 5 Network 6 Terminal 7 Sensor 8 Beacon 8F Spoofing beacon 8T Legitimate beacon 9 Hardware 20 Data acquisition unit 21 Trajectory extraction Unit 22 Position estimation unit 23 Error determination unit 24 Error position estimation unit 90 Bus 91 Processor 92 Memory 93 Storage device 94 Network interface circuit 95 Input device

Claims (15)

The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. An acquisition unit for acquiring position-time information and second position-time information acquired at a second point by the terminal at a second time after the reception time.
The average movement speed between the first point and the second point of the terminal is calculated from the first position time information and the second position time information, and the average movement speed is equal to or less than a predetermined value. When the distance between the first point and the second point is equal to or greater than a predetermined distance, the first time interval between the first time and the reception time and the said. A correction is made to at least one of the second time intervals between the reception time and the second time, and the correction is made to at least one of the first time interval and the second time interval after the correction. Based on this, a position estimation unit that estimates the position of the terminal at the reception time and estimates the position of the transmitter based on the estimation.
A position estimation device characterized by comprising. The position estimation device according to claim 1, wherein the position estimation unit performs the correction with respect to the second time interval. The position estimation unit is
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is less than the predetermined distance, the correction is performed, and the first after the correction is performed. The position of the terminal at the reception time is estimated based on at least one of the time interval and the second time interval.
The position estimation device according to claim 1 or 2. The position estimation unit is
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is less than the predetermined distance, the correction is not performed and the first time is not performed. The position of the terminal at the reception time is estimated based on at least one of the interval and the second time interval.
The position estimation device according to claim 1 or 2. The position estimation unit is
When the correction is performed, the position of the terminal at the reception time is estimated by performing linear interpolation using at least one of the first time and the second time after the correction.
When the correction is not performed, the position of the terminal at the reception time is estimated by performing linear interpolation using at least one of the first time and the second time.
The position estimation device according to any one of claims 1 to 4, wherein the position estimation device is characterized. The position estimation unit is
When making the correction, the position of the terminal at the reception time is estimated based on the shorter time interval of the first time interval and the second time interval after the correction.
When the correction is not performed, the position of the terminal at the reception time is estimated based on the shorter time interval of the first time interval and the second time interval.
The position estimation device according to any one of claims 1 to 5, wherein the position estimation device is characterized. The position estimation unit is
The coordinates of the position of the transmitter are calculated by weighting the estimated coordinates of the position of the terminal.
The weight is
When the correction is performed by the position estimation unit, it is calculated using at least one of the first time interval and the second time interval after the correction.
If the correction is not performed by the position estimation unit, it is calculated using at least one of the first time interval and the second time interval.
The position estimation device according to any one of claims 1 to 6, wherein the position estimation device is characterized. The seventh aspect of claim 7, wherein at least one of the signal strength and the distance between the first point and the second point is used for the calculation of the weight. Position estimation device. The position estimation device further
The difference distance between the estimated position of the transmitter and the estimated position of the terminal used for estimating the position of the transmitter is calculated.
An error determination unit that calculates an error score based on the difference distance and the weight, and determines that the signal is not transmitted from the transmitter when the error score is larger than the threshold value.
The position estimation device according to claim 7 or 8, wherein the position estimation device is provided. The position estimation device further includes an error position estimation unit.
The error position estimation unit is
The difference distance between the estimated position of the transmitter and each estimated position of one or more terminals used for estimating the position of the transmitter is calculated.
For each terminal, an error score is calculated based on the difference distance and the weight.
When at least one of the error scores of the one or more terminals is larger than the threshold value, the signal received by the terminal having the highest error score of the one or more terminals is the transmitter. Judging that it was transmitted from a different transmitter,
Of the one or more terminals, the estimation of the estimated position of the transmitter is derived again based on the estimated position of the terminal determined to have received the signal transmitted from the transmitter.
Of the one or more terminals, the estimated position of the other transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the other transmitter.
The position estimation device according to claim 7 or 8. The error position estimation unit is
The difference distance between each estimated position of the one or more terminals and the estimated position of the transmitter is calculated.
The difference distance between each estimated position of the one or more terminals and the estimated position of the other transmitter is calculated.
When the difference distance between the estimated position of the terminal and the estimated position of the transmitter is equal to or less than the difference distance between the estimated position of the terminal and the estimated position of the other transmitter, the terminal receives the reception time. It is determined that the signal has been received from the transmitter in
When the difference distance between the estimated position of the terminal and the estimated position of the transmitter is larger than the difference distance between the estimated position of the terminal and the estimated position of the other transmitter, the terminal has the reception time. Determined that a signal was received from the other transmitter in
Of the one or more terminals, the estimated position of the transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the transmitter.
Of the one or more terminals, the estimated position of the other transmitter is derived based on the estimated position of the terminal determined to have received the signal transmitted from the other transmitter.
The position estimation device according to claim 10. The error position estimation unit is
The terminal determined to have received the signal transmitted from the transmitter is classified into the first cluster, and the terminal determined to have received the signal transmitted from the other transmitter is classified into the second cluster. Classify into
The estimated position of the transmitter is derived based on the estimated position of the terminal in the first cluster.
Deriving the estimated position of the other transmitter based on the estimated position of the terminal in the second cluster.
The position estimation device according to claim 10 or 11. The position estimation device according to any one of claims 1 to 12, wherein the transmitter is a beacon. The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. The position-time information and the second position-time information acquired at the second point at the second time after the reception time by the terminal are acquired.
From the first position / time information and the second position / time information, the average moving speed between the first point and the second point of the terminal is calculated.
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is equal to or more than a predetermined distance, the time between the first time and the reception time is reached. The first time interval and at least one of the second time intervals between the reception time and the second time are corrected, and the first time interval and the second time interval after the correction are corrected. The position of the terminal at the reception time is estimated based on at least one of the time intervals of the above, and the position of the transmitter is estimated based on the estimation.
A position estimation program that causes a position estimation device to execute processing. The reception time when the terminal receives the signal from the transmitter, the strength of the signal received by the terminal, and the first time acquired by the terminal at the first point at the first time before the reception time. The position-time information and the second position-time information acquired at the second point at the second time after the reception time by the terminal are acquired.
From the first position / time information and the second position / time information, the average moving speed between the first point and the second point of the terminal is calculated.
When the average moving speed is equal to or less than a predetermined value and the distance between the first point and the second point is equal to or more than a predetermined distance, the time between the first time and the reception time is reached. The first time interval and at least one of the second time intervals between the reception time and the second time are corrected, and the first time interval and the second time interval after the correction are corrected. The position of the terminal at the reception time is estimated based on at least one of the time intervals of the above, and the position of the transmitter is estimated based on the estimation.
A position estimation method performed by a position estimation device.

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