JP7285981B1 - Position estimation device, automatic driving system, and position estimation method - Google Patents

Abstract

A position estimation device capable of estimating its own position with high accuracy and robustness is obtained. A position estimation device (400) of the present disclosure includes a satellite signal reception unit (120) that receives a satellite signal transmitted from a positioning satellite (11), and a beacon that receives a beacon signal transmitted from an anchor installed on the roadside by a tag node. A signal communication unit 130, a satellite signal positioning unit 140 that acquires satellite positioning position information based on a satellite signal, a beacon signal positioning unit 130 that acquires beacon positioning position information based on a beacon signal, and a beacon positioning position information and a satellite positioning position. and a self-position estimation unit 170 that estimates the self-position based on the information. [Selection drawing] Fig. 1

Description

The present application relates to a position estimation device, an automatic driving system, and a position estimation method.

In order to realize automatic operation of a mobile object, it is necessary to always accurately grasp the self-position of the mobile object. As a method for estimating the self-position of a mobile object, there is a method using satellite signals when the mobile object runs outdoors. In addition, in an environment where it is difficult to receive satellite signals, such as indoors, there is a method of using signals from a plurality of beacon signal transmitters arranged on the roadside.

As mentioned above, the communication method that can acquire the position information of the mobile object differs depending on the location where the mobile object runs. There is a demand for a technology for switching between communication methods.

In the position detection system described in Patent Document 1, in measuring the self-position of a mobile object, positioning is performed using satellite signals outdoors, while positioning is performed using beacon signals indoors. can reliably detect its own position.

JP 2019-132627 A

According to the position detection system described in Patent Document 1, when the self-position can be determined by both satellite and beacon positioning systems, it is predetermined to use the beacon positioning system. When the system is normal and beacon positioning is normal, beacon positioning is forcibly selected regardless of whether the accuracy or stability is good or bad, so there is a problem that satellite positioning information is not utilized. In addition, when positioning cannot be performed by satellite positioning and when positioning cannot be performed by beacon positioning, there is also a problem that the state in which positioning cannot be performed continues.

The present disclosure has been made to solve the above problems, and aims to provide a position estimation device, an automatic driving system, and a position estimation method for estimating the self-position of a mobile object with high accuracy.

The position estimation device disclosed in the present application includes:
a satellite signal receiving unit that receives a satellite signal transmitted from a positioning satellite;
a beacon signal communication unit for receiving, by a tag node, a beacon signal transmitted from an anchor installed on the roadside;
a satellite signal positioning unit that acquires satellite positioning position information based on the satellite signal;
a beacon signal positioning unit that acquires beacon positioning position information based on the beacon signal;
a self-position estimation unit that estimates a self-position based on the beacon positioning position information and the satellite positioning position information;
a signal quality evaluation unit that generates a signal quality evaluation value for each communication state of the beacon signal and the satellite signal;
The self-location estimating unit uses the beacon positioning position information selected based on the signal quality evaluation value of the beacon signal and the satellite positioning position information selected based on the signal quality evaluation value of the satellite signal. Based on the signal quality evaluation value generated by the signal quality evaluation unit, the self-position is estimated, and a weighting factor is generated for each of the beacon positioning position information and the satellite positioning position information.

The automatic driving system disclosed in the present application is
the above-described position estimation device mounted on the own vehicle;
A travel route generating device mounted on the own vehicle for generating a travel route from the own vehicle position to a target point by using the own vehicle position of the own vehicle output from the position estimation device. and,
A vehicle control device that is mounted on the own vehicle and sets a target trajectory and a target travel speed for executing automatic driving control of the own vehicle on the generated travel route.

The position estimation method disclosed in the present application comprises:
a satellite signal reception step of receiving a satellite signal transmitted from a positioning satellite;
a beacon signal communication step of receiving, by a tag node, a beacon signal transmitted from an anchor installed on the roadside;
a satellite signal positioning step of obtaining satellite positioning position information based on the satellite signals;
a beacon signal positioning step of obtaining beacon positioning position information based on the beacon signal;
a self-position estimation step of estimating self-position based on the beacon positioning position information and the satellite positioning position information;
a signal quality evaluation step of generating a signal quality evaluation value from communication conditions of each of the beacon signal and the satellite signal;
In the self-position estimation step, the beacon positioning position information selected based on the signal quality evaluation value of the beacon signal, and the satellite positioning position information selected based on the signal quality evaluation value of the satellite signal. Based on this, the self-position is estimated, and a weighting factor is generated for each of the beacon positioning position information and the satellite positioning position information based on the signal quality evaluation value generated by the signal quality evaluation step.

According to the position estimation device disclosed in the present application, the self-position is estimated based on the combination of the satellite signal and the beacon signal, so it is possible to obtain a position estimation device capable of estimating the self-position with high accuracy and robustness. Effective.

According to the position estimation method disclosed in the present application, the self-position is estimated based on the combination of the satellite signal and the beacon signal. Effective.

According to the automatic driving system disclosed in the present application, the vehicle position information is estimated with high accuracy by the position estimation device and the position estimation method described above. It is effective in realizing operation control.

1 is a functional block diagram showing the configuration of a position estimation device according to Embodiment 1; FIG. FIG. 2 is a schematic diagram for explaining the positional relationship between the vehicle, positioning satellites, and anchors when the vehicle is viewed from above in the vehicle equipped with the position estimation device according to Embodiment 1; FIG. 2 is a schematic diagram for explaining the positional relationship between the vehicle, positioning satellites, and anchors when the vehicle is viewed from the horizontal direction in the vehicle equipped with the position estimation device according to Embodiment 1; FIG. 4 is a flow chart diagram showing a position estimation method according to Embodiment 1; FIG. 4 is a flow chart diagram showing a position estimation method according to Embodiment 1; FIG. 10 is a flow chart diagram showing a position estimation method according to Embodiment 2; FIG. 10 is a flow chart diagram showing a position estimation method according to Embodiment 2; FIG. 11 is a flow chart diagram showing a position estimation method according to Embodiment 3; FIG. 11 is a functional block diagram showing the configuration of an automatic driving system according to Embodiment 4; FIG. 10 is a schematic diagram of a vehicle equipped with an automatic driving system according to Embodiment 4; It is a figure which shows the hardware constitutions which implement|achieve the position estimation apparatus which concerns on Embodiment 1-3, and the automatic driving system which concerns on Embodiment 4. FIG. It is a figure which shows the hardware constitutions which implement|achieve the position estimation apparatus which concerns on Embodiment 1-3, and the automatic driving system which concerns on Embodiment 4. FIG.

Embodiment 1.
<Configuration of position estimation device according to Embodiment 1>
FIG. 1 is a functional block diagram showing the configuration of a position estimation device according to Embodiment 1. FIG. Position estimation apparatus 400 according to Embodiment 1 includes beacon signal communication section 110, satellite signal reception section 120, beacon signal positioning section 130, satellite signal positioning section 140, time management section 150, and signal quality evaluation section. 160 and a self-position estimation unit 170 .

The beacon signal communication unit 110 has a tag node 13, and the tag node 13 receives a beacon signal transmitted from the anchor node 12a of one or more anchors 12 installed on the roadside. The beacon signal contains position information of the anchor 12 . The position information of the anchor 12 includes at least the position, distance, angle and signal quality of the anchor 12 . Beacon signal communication section 110 outputs the received beacon signal to beacon signal positioning section 130 . A tag node 13 can also communicate with anchor nodes 12 a of multiple anchors 12 .

The beacon signal communication unit 110 receives positioning timing from the time management unit 150 via the beacon signal positioning unit 130 . Note that the beacon signal communication unit 110 may directly receive the positioning timing instruction from the time management unit 150 . Also, the beacon signal communication unit 110 may have an angle measurement function using a plurality of antennas installed in the tag node 13 and acquire information regarding the direction of the beacon signal.

The satellite signal receiver 120 receives satellite signals transmitted from one or more positioning satellites 11 . The satellite signal includes at least the position, distance and signal quality of the positioning satellite 11 . Satellite signal reception section 120 outputs the received satellite signal to satellite signal positioning section 140 . It should be noted that, when the reinforcement signal from the positioning satellite 11 or the cellular network is applied, the reinforcement signal is also included in part of the satellite signal.

An example of the satellite communication system is CDMA (Code Division Multiple Access). An example of a beacon communication method is IR-UWB (Impulse-Radio Ultra Wide Band). However, the communication schemes are not limited to those described above, as long as the objectives of the present disclosure can be met.

The beacon signal positioning unit 130 obtains position information of the anchor 12 from the received beacon signal, including the position of one or more anchor nodes 12a, the distance from the anchor node 12a to the tag node 13, and the direction of the beacon signal (hereinafter referred to as beacon (referred to as positioning location information).

The satellite signal positioning unit 140 acquires position information of the positioning satellites 11 (hereinafter referred to as satellite positioning position information) from the received satellite signals.

The time management unit 150 manages reception timing of satellite signals transmitted from the positioning satellites 11 . The time management unit 150 transmits a positioning timing instruction to the beacon signal communication unit 110 or the beacon signal positioning unit 130, and synchronizes the positioning timing of the beacon signal positioning unit 130 with the satellite signal reception timing. 130 and the satellite signal positioning unit 140 are synchronized.

The signal quality evaluation unit 160 generates a signal quality evaluation value V from the communication state of beacon signals and satellite signals. In order to quantitatively evaluate the communication state of the satellite signal, the signal quality evaluation unit 160 evaluates, for example, a combination of either one or both of the satellite signal Dilution Of Precision (DOP) and the satellite signal strength. Based on this, a signal quality evaluation value V is generated.

In order to quantitatively evaluate the communication state of the beacon signal, the signal quality evaluation unit 160 performs, for example, the correlation between the beacon signal strength of the beacon signal communication unit 110 and the pattern signal shared between the anchor node 12a and the tag node 13. A signal quality estimate V is generated based on either one of the values or a combination of both.

Based on the signal quality of the satellite signal and the beacon signal, for example, based on the signal quality evaluation value V, the signal quality evaluation unit 160 calculates the satellite signal (that is, satellite positioning position information) and the beacon signal (that is, , beacon positioning location information). As an example of the method of selecting each signal, there is a method of presetting an evaluation threshold value V _th for the signal quality evaluation value V, and using only signals with a signal quality evaluation value V equal to or higher than the evaluation threshold value V _th for estimating the self-location. .

Further, when three or more satellite signals having signal quality evaluation values V equal to or higher than the evaluation threshold value _Vth are obtained, the self-position is estimated using only the satellite signals, or the signal quality evaluation value V is equal to or _higher than the evaluation threshold value Vth. When three or more beacon signals are obtained, the self-position is estimated using only the beacon signals, and both the signal quality evaluation value V of the satellite signal and the signal quality evaluation value V of the beacon signal are less than the evaluation threshold value _Vth . In this case, self-position estimation section 170 may apply a selection method of estimating self-position using both beacon positioning position information and satellite positioning position information. However, in this case, it is necessary to set a threshold value that is lower than the evaluation threshold value _Vth and use it as a criterion for selecting each signal.

The self-position estimation unit 170 estimates the self-position based on both the beacon positioning position information and the satellite positioning position information, and the signal quality evaluation value V of each of the beacon signal and the satellite signal. Self-position estimation section 170 outputs information on the estimated self-position to the outside of position estimation device 400 . Regarding the signal quality evaluation of beacon signals and satellite signals, signal quality information included in advance in beacon positioning position information and satellite positioning position information may be used.

As a method for the self-location estimation unit 170 to estimate the self-location based on the signal quality evaluation value V, for example, a method of generating a weighting factor for the beacon positioning position information and the satellite positioning position information based on the signal quality evaluation value V can be mentioned. be done. The weighting factor is set relatively large as the signal quality evaluation value V increases. Details of the weighting factor will be described later.
The above is the description of the configuration of the position estimation device 400 according to the first embodiment.

A situation in which position estimation device 400 according to Embodiment 1 operates will be described. FIG. 2 is a schematic diagram illustrating the positional relationship between the vehicle 10 equipped with the position estimation device 400 and the anchor 12 on which the positioning satellite 11 and the anchor node 12a are installed when the vehicle 10 is viewed from above. FIG. 3 is a schematic diagram for explaining the positional relationship between the vehicle 10 equipped with the position estimation device 400 and the anchor 12 on which the positioning satellite 11 and the anchor node 12a are installed when the vehicle 10 is viewed from the horizontal direction. be. The vehicle 10 is merely an example of a moving body, and the position estimation device 400 according to Embodiment 1 may be applied to a moving body other than the vehicle 10. Further, the vehicle 10 may be an automatically driven vehicle 10a, and by installing the position estimation device 400 according to Embodiment 1 in the automatically driven vehicle 10a, even smoother automatic driving can be realized. An automatic driving system including the position estimation device 400 according to Embodiment 1 will be described in detail in Embodiment 4.

As shown in FIG. 2, on the upper surface of the vehicle 10, a tag node 13 that is part of the beacon signal communication unit 110 and a satellite signal reception antenna 14 that is part of the satellite signal reception unit 120 are installed. Above the vehicle 10, two positioning satellites 11 transmit satellite signals toward the ground. On the ground, two anchors 12 are installed on the side of a road (not shown), and beacon signals are transmitted from anchor nodes 12a to vehicles 10 traveling on the road.

In position estimation apparatus 400 according to Embodiment 1, satellite signal positioning section 140 obtains position information (x _i , y _i , z _i ) of positioning satellite 11, positioning Using the distance r _i from the satellite 11 to the satellite signal receiving unit 120 and the speed of light c, the position information (x, y, z) of the vehicle 10 and the clock error t of the satellite signal receiving unit 120 are unknown. Derive the equation shown in Equation (1).

Equation (1) is established for each satellite signal of each positioning satellite 11 . In the case of self-positioning using only the positioning satellites 11, it is necessary to receive satellite signals from three or more positioning satellites 11. FIG. However, position estimation apparatus 400 according to Embodiment 1 estimates its own position by combining both satellite signals and beacon signals. By using the above beacon signals in combination, it is possible to estimate the self-position. Furthermore, when distance information and angle information are simultaneously obtained from one anchor 12, the satellite signal from one positioning satellite 11 and the beacon signal from one anchor 12 can also be used to estimate the self-position.

In beacon communication, position information (beacon positioning position information) obtained from beacon signals transmitted from anchor nodes 12a of three or more anchors 12 is used to estimate the self position using the principle of triangulation. . However, position estimation apparatus 400 according to Embodiment 1 can estimate its own position by combining both satellite signals and beacon signals. Even if only signals can be received, it is possible to estimate the self-position by combining satellite signals transmitted from two or more positioning satellites 11 . Furthermore, as described above, when distance information and angle information are obtained simultaneously by one anchor 12, the combination of the satellite signal from one positioning satellite 11 and the beacon signal from one anchor 12 can also be used to determine the self-position. can be estimated.

In position estimation apparatus 400 according to Embodiment 1, if the total number of satellite signals transmitted from positioning satellites 11 at different positions and beacon signals transmitted from anchor nodes 12a of anchors 12 at different positions is three or more, , the self-location can be estimated. However, as described above, even one satellite signal and one beacon signal may be sufficient to estimate the self-position. That is, in principle, position estimation apparatus 400 according to Embodiment 1 is based on the position of positioning satellite 11, the distance between vehicle 10 and positioning satellite 11, the position of anchor 12 placed on the roadside, and the position of anchor 12 and vehicle 10. The self-location is estimated using both the distances between the tag nodes 13 installed in .

<Position Estimation Method According to Embodiment 1>
4 and 5 are flowcharts showing a position estimation method using position estimation device 400 according to Embodiment 1. FIG. The position estimation method according to Embodiment 1 performs a series of self-position estimation loop processes shown in the flowchart of FIG. It is repeatedly executed at a predetermined cycle (for example, 1 second).

In step S<b>102 , the satellite signal receiving unit 120 receives satellite signals transmitted from the positioning satellites 11 . The satellite signal positioning unit 140 obtains position information and signal quality at the same time by positioning based on the satellite signal, and proceeds to the process of step S103. The position information and signal quality of the positioning satellites 11 are included in the satellite positioning position information.

In step S103, the beacon signal communication unit 110 receives a beacon signal transmitted from the anchor node 12a of the anchor 12 installed on the roadside. The beacon signal positioning unit 130 obtains position information and signal quality at the same time by positioning based on the beacon signal, and proceeds to the process of step S104. The location information and signal quality of the anchor 12 are included in the beacon positioning location information.

In step S104, the signal quality evaluation unit 160 selects satellite signals and beacon signals to be used for self-position estimation based on the signal quality of the satellite signals and beacon signals, and proceeds to the process of step S105.

In step S105, the self-position estimation unit 170 estimates the self-position based on the selected satellite signals and beacon signals.

FIG. 5 is a flow chart for explaining the contents of the processing of step S104 in the flow chart of FIG.

In step S201, the signal quality evaluation unit 160 determines whether or not there are three or more captured positioning satellites 11 with good signal quality. The signal quality may be information included in the satellite positioning position information.

If it is determined in step S201 that the number of captured positioning satellites 11 with good signal quality is three or more (if YES), the process proceeds to step S206, and only satellite signals are used to estimate the self-position. Yes, that is, in a state in which only satellite signals have been selected, the process proceeds to step S105.

If it is determined in step S201 that the number of captured satellite signals with good signal quality is less than three (NO), the process proceeds to step S202.

If it is determined in step S202 that the number of captured beacon signals with good signal quality is 3 or more (if YES), the process proceeds to step S207, and only beacon signals are used to estimate the self-position. , that is, in a state in which only the beacon signal is selected, the process proceeds to step S105.

If it is determined in step S202 that the number of captured beacon signals with good signal quality is less than three (NO), the process proceeds to step S203.

In step S203, the satellite signal with good signal quality and the beacon signal with good signal quality are combined, and the process proceeds to step S105.

As can be seen from the above description, the satellite signals and beacon signals selected in step S105 are only three or more satellite signals with good signal quality when the process of step S206 is performed, and when the process of step S207 is performed, is a combination of only three or more beacon signals with good signal quality, and a combination of less than three satellite signals with good signal quality and less than three beacon signals with good signal quality after the process of step S203.

In the above description, only satellite signals are used in the case of three or more satellite signals with good signal quality. can be set to the number of Beacon signals are similar to satellite signals. For example, if the number of complements of satellite signals is set to 4 or more when only satellite signals are used, and the required number of complements of beacon signals is set to 4 or more when only beacon signals are used, when satellite signals and beacon signals are combined, , less than 4 satellite signals and less than 4 beacon signals are the required supplemental numbers. This is because, when minimizing errors in satellite signals and beacon signals and removing outliers, etc., are taken into consideration, the greater the number of signals, the more accurately and stably the positioning can be performed. This is also because even when the DOP is taken into account, the greater the number of signals, the higher the possibility of improving the DOP.
The above is the description of the position estimation method according to the first embodiment.

In the position estimation method according to Embodiment 1, the number of satellite signals with good signal quality necessary for positioning the self-position in satellite positioning does not reach the required number of supplements, or beacons with good signal quality in beacon positioning Even if the signal does not reach the required number of acquisitions, the self-position is estimated by combining the information of the satellite signal and the information of the beacon signal rather than selecting either one. As a result, even in the situation described above, it is possible to estimate the self-position with high accuracy and robustness.

<Effect of Embodiment 1>
As described above, according to the position estimation device and the position estimation method according to Embodiment 1, even if the required number of supplements is not reached with only satellite signals, or even if the number of supplements is not reached with only beacon signals, Since the self-position is estimated based on a combination of satellite signals and beacon signals with good signal quality, there is an effect that a position estimation device and a position estimation method capable of estimating the self-position with high accuracy and robustness are obtained. .

Embodiment 2.
6 and 7 are flowcharts showing a position estimation method according to Embodiment 2. FIG. The position estimation method according to the second embodiment performs a series of self-position estimation loop processes shown in the flowchart of FIG. It is repeatedly executed at a predetermined cycle (for example, 1 second). A position estimation device that executes the position estimation method according to the second embodiment is the same as the position estimation device 400 described in the first embodiment.

The position estimation method according to Embodiment 2 differs from the position estimation method according to Embodiment 1 in that, in the flowchart shown in FIG. In addition, in the flowchart shown in FIG. 7, each process of step S404 and step S405 is added after the process of step S203 of the first embodiment.

<Position estimation method according to Embodiment 2>
In the position estimation method according to Embodiment 2, first, the signal quality evaluation unit 160 generates the signal quality evaluation value V from the respective communication states of the beacon signal and the satellite signal. For the signal quality, information on signal quality included in advance in the satellite positioning position information and the beacon positioning position information may be used. Next, based on the signal quality evaluation value V, the self-position estimation unit 170 generates a weighting factor for each of the beacon positioning position information and the satellite positioning position information.

<Application of weighting factor in self-location estimation>
Regarding the application of weighting factors in estimating the self-position, as an example, application of weighting factors when using the positional information of the anchor 12 included in the beacon positioning positional information and the positional information of the positioning satellites 11 included in the satellite positioning positional information. Examples are illustrated below.

An example of self-position estimation using weighting factors is described below. The estimated value of the self-position of the vehicle 10 is represented by three-dimensional coordinates as (x _s , y _s , z _s ). In addition, regarding the position information of the positioning satellite 11 and the position information of the anchor 12, without distinguishing whether the position information is caused by one of them, the N radio wave sources R ₁ , R ₂ , . . . _N 's location information.

For each position represented by three _- dimensional _{coordinates of N} radio wave sources R ₁ , R _{2 ,} . The _source R ₂ is _represented by (X ₂ , Y _{2 ,} Z ₂ ), _. Also, each of the _N radio wave sources R ₁ , R ₂ , . Regarding the distance between the vehicle 10 and each radio wave source positioned between the radio wave source R1, the radio wave source _R1 is the distance _d1 , the radio wave source _R2 is the distance _d2 , _. is the distance _dn . If the signal quality of signals transmitted from all radio wave sources is good, the squared error function F(x _s , y _s , z _s ) represented by the following equation (1) should be minimized. is used to estimate the self-position.

On the other hand, when the signals transmitted from each radio wave source include signals of good signal quality and signals of poor signal quality, the square error function F(x _s , y _s , z _s ), apply the weighting factors described below.

Based on the signal quality evaluation value _Vn generated by the signal quality evaluation unit 160 for each of the N radio wave sources _Rn , a weighting factor _Wn for the position of the anchor 12 and the position of the positioning satellite 11 is generated. Applying the weighting factor W _n to equation (2) above yields equation (3) below for the squared error function F(x _s , y _s , z _s ).

When the signal quality of the signal transmitted from the radio wave source is good, that is, when the signal quality evaluation value _Vn is high, the weighting factor _Wn is set relatively large. On the other hand, when the signal quality is poor, that is, when the signal quality evaluation value _Vn is low, the weighting factor _Wn is set relatively small. Note that the weighting factor _Wn may be determined based on a certain rule from the viewpoint of communication stability. Also, the weighting factor _Wn may be determined by AI (artificial intelligence), specifically machine learning or deep learning.

To estimate the self-position of the vehicle 10, the method of least squares is applied to minimize the square error function F(x _s , y _s , z _s ) expressed by Equation (3). The coordinates calculated by the method of least squares are the estimated self-position of the vehicle 10 .

As described above, signal quality evaluation value V is generated in signal quality evaluation section 160 . For satellite signals, the signal quality evaluation value V is generated, for example, based on a combination of one or both of the DOP of the satellite signal and the satellite signal strength.

In the case of the beacon signal, the signal quality evaluation value V is, for example, one of the beacon signal strength by the beacon signal communication unit 110 and the correlation value of the pattern signal shared between the anchor node 12a and the tag node 13. or based on a combination of both.

The correlation value of the pattern signal shared between the anchor node 12a and the tag node 13 is obtained by transmitting a pattern signal called a preamble multiple times before starting beacon communication in the case of positioning by the IR-UWB communication system, The beacon signal receiving side compares whether or not the pattern signals received are correct signals, and when the pattern signals match more than a threshold number of times, the pattern signal on the anchor node 12a side when starting beacon communication. It means the correlation value between the pattern signals on the tag node 13 side.

<Position estimation method according to Embodiment 2>
Regarding the position estimation method according to the second embodiment, only processing different from the position estimation method according to the first embodiment will be described.

In step S304 of the flowchart shown in FIG. 6, the signal quality evaluation unit 160 selects satellite signals and beacon signals used for self-position estimation based on the signal quality of the satellite signals and beacon signals, A weighting factor is set for each distance between the satellite 11 and the anchor 12, and the process proceeds to step S105.

In step S404 of the flowchart shown in FIG. 7, each signal having good signal quality is selected from the combination of the satellite signal transmitted from each positioning satellite 11 and the beacon signal transmitted from each anchor 12. FIG. A total of three or more selected signals is desirable. However, as described above, when distance information and angle information can be obtained simultaneously by one anchor 12, the combination of the satellite signal from one positioning satellite 11 and the beacon signal from one anchor 12, that is, Self-position estimation is possible even if the sum of the selected signals is two. In step S404, as a method of selecting signals with good signal quality, signals with good DOP are selected, and the process proceeds to step S405.

In step S405, a weighting factor is further set for each selected signal based on the signal quality, and the process proceeds to step S105 shown in FIG.
The above is the description of the position estimation method according to the second embodiment.

<Effect of Embodiment 2>
As described above, according to the position estimation method according to Embodiment 2, the weighting factor based on the communication state is applied to the position information by each satellite signal and each beacon signal, so that the self-position can be estimated with high accuracy and robustness. It is effective in obtaining a position estimation method capable of

Embodiment 3.
FIG. 8 is a flowchart showing a position estimation method according to Embodiment 3. FIG. The position estimation method according to Embodiment 3 performs a series of self-position estimation loop processes shown in the flowchart of FIG. It is repeatedly executed at a predetermined cycle (for example, 1 second). A position estimation device that executes the position estimation method according to the third embodiment is the same as the position estimation device 400 described in the first embodiment.

In the position estimation method according to the third embodiment, each process of steps S106 and S107 is added after the process of step S105 in the flowchart of FIG. 6 showing the position estimation method according to the first embodiment.

In the position estimation method according to Embodiment 3, time management section 150 manages the reception timing of satellite signals transmitted from positioning satellites 11 . The time management unit 150 synchronizes the positioning timing of the beacon signal positioning unit 130 with the satellite signal reception timing of the satellite signal positioning unit 140, thereby adjusting the positioning timing of the beacon signal positioning unit 130 and the reception timing of the satellite signal positioning unit 140. Synchronize.

<Position estimation method according to the third embodiment>
As for the position estimation method according to the third embodiment, only processing different from the position estimation method according to the first embodiment will be described below.

In step S106 of the flowchart shown in FIG. 8, the time management unit 150 determines whether there is a difference between the reception timing of the satellite signal transmitted from the positioning satellite 11 and the positioning timing of the beacon signal transmitted from the anchor 12. judge.

If it is determined that there is a deviation between the reception timing of the satellite signal and the positioning timing of the beacon signal (if YES), the process proceeds to step S107. In step S107, by changing the positioning timing of the beacon signal, the deviation between the reception timing of the satellite signal and the positioning timing of the beacon signal is eliminated, and the positioning timing of the beacon signal positioning unit 130 and the positioning timing of the satellite signal positioning unit 140 are adjusted. are synchronized with each other, and the loop processing of step S108 is performed.

If it is determined that there is no deviation between the reception timing of the satellite signal and the positioning timing of the beacon signal (in the case of NO), loop processing of step S108 is performed.
The above is the description of the position estimation method according to the third embodiment.

<Effect of Embodiment 3>
As described above, according to the position estimation method according to Embodiment 3, the positioning timing of the beacon signal positioning unit and the reception timing of the satellite signal positioning unit are synchronized. This has the effect of providing a possible position estimation method.

In the description of the first to third embodiments above, the distance includes all information equivalent to the distance. For example, when using the propagation delay time of radio waves or the phase of carrier waves, it is the number of waves of radio waves. Positioning calculation can also be performed by the roadside device or a server on the Internet instead of the position estimation device 400 mounted on the mobile object. Furthermore, the positioning result may be stabilized using motion information of the moving body using an inertial measurement device or the like.

Regarding whether or not to perform a calculation combining both the satellite positioning position information from the positioning satellites 11 and the beacon positioning position information from the anchors 12, the calculation may always be performed by combining the two. The combination may be dynamically switched, such as the satellite signal alone or the anchor 12 beacon signal alone. When dynamically switching the combination, the switching may be performed with hysteresis instead of sensitively switching with one threshold value based on the signal quality.

Embodiment 4.
FIG. 9 is a functional block diagram showing the configuration of an automatic driving system 500 according to Embodiment 4. As shown in FIG. FIG. 10 is a schematic diagram of an automatically driving vehicle 10a equipped with an automatically driving system 500 according to the fourth embodiment. Automatic driving system 500 includes position estimation device 400 , travel route generation device 510 and vehicle control device 520 according to Embodiment 1. FIG.

<Configuration of automatic driving system according to Embodiment 4>
As described above, the position estimation device 400 outputs the position information of the own vehicle position of the automatically driven vehicle 10a estimated based on the received satellite signals and beacon signals to the travel route generation device 510 .

The travel route generation device 510 uses the vehicle position information of the automatically driven vehicle 10a output from the position estimation device 400 to generate a travel route from the vehicle position of the automatically driven vehicle 10a to the target point. Note that a known method can be applied to generate the travel route.

The vehicle control device 520 sets a target trajectory and a target vehicle speed, which are target control amounts required for the automatically driven vehicle 10a to travel on the travel route generated by the travel route generation device 510, and further sets the target trajectory and the target vehicle speed. A target steering amount and a target acceleration/deceleration required to follow the vehicle speed are calculated. A known calculation method can be applied to the calculation of the target steering amount and the target acceleration/deceleration.
The above is the description of the configuration of the automatic driving system 500 .

<Operation of automatic driving system according to Embodiment 4>
Vehicle control of the automatically driven vehicle 10a by the automatic driving system 500 will be described below.
The target steering amount and the target acceleration/deceleration, which are the target control amounts calculated by the vehicle control device 520 of the automatic driving system 500, are output to the actuator 530, and the automatic driving control of the automatic driving vehicle 10a is executed.

Actuator 530 includes an electric power steering (EPS) controller 531 , power train controller 532 , brake controller 533 , EPS unit 535 , power train unit 536 and brake unit 537 .

The actuator 530 controls the EPS, the brake, and the accelerator so that the automatically driven vehicle 10a follows the target steering amount and target acceleration/deceleration.

The EPS controller 531 controls the EPS unit 535 based on the target steering amount output from the automatic driving system 500 . The EPS controller 531 can control, for example, the steering angle for the autonomous vehicle 10a to travel along the target locus.

The powertrain controller 532 controls the powertrain unit 536 so as to achieve the target acceleration/deceleration output from the automatic driving system 500 . Also, when the driver performs speed control instead of automatic driving control, the power train unit 536 is controlled based on the amount of depression of the accelerator pedal.

The brake controller 533 controls the brake unit 537 so as to achieve the target acceleration/deceleration output from the automatic driving system 500 . Also, when the driver performs speed control instead of automatic driving control, the brake unit 537 is controlled based on the amount of depression of the brake pedal.

<Effect of Embodiment 4>
As described above, according to the automatic driving system according to the fourth embodiment, the vehicle position information of the automatically driven vehicle is calculated with high accuracy by the position estimation device and the position estimation method according to the first to third embodiments. It is effective in realizing stable automatic driving control based on the vehicle position information.

The configuration in which the function of each component of the position estimation device 400 according to Embodiments 1 to 3 and the automatic driving system 500 according to Embodiment 4 is realized by either hardware or software has been described above. . However, it is not limited to this, and some components of the position estimation device 400 according to Embodiments 1 to 3 and the automatic driving system 500 according to Embodiment 4 are realized by dedicated hardware, It may be a configuration in which some of the components of are realized by software or the like.

For example, as shown in FIGS. 11 and 12, some components are implemented by a processing circuit 300 as dedicated hardware, and some other components are implemented by a processing circuit as a processor 301. 300 can realize the function by reading and executing a program for causing a computer or the like to execute the position estimation method according to Embodiments 1 to 3 stored in storage device 302 .

Furthermore, as shown in FIG. 12, the setting data used by each functional unit of the position estimation device 400 according to Embodiments 1 to 3 and the automatic driving system 500 according to Embodiment 4 is part of software, that is, A program 305 for causing a computer or the like to execute the position estimation methods according to Embodiments 1 to 3 may be installed in the storage device 302 from the recording medium 304 storing the program 305 .

As described above, the position estimation device 400 according to Embodiments 1 to 3 and the automatic driving system 500 according to Embodiment 4 implement the functions described above using hardware, software, or a combination thereof. can be done.

While this disclosure describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more of the embodiments may vary from particular embodiment to embodiment. The embodiments are applicable singly or in various combinations without being limited to the application.

Accordingly, numerous variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, modification, addition or omission of at least one component, extraction of at least one component, and combination with components of other embodiments shall be included.

10 vehicle, 10a self-driving vehicle, 11 positioning satellite, 12 anchor, 12a anchor node, 13 tag node, 14 antenna for satellite signal reception, 110 beacon signal communication unit, 120 satellite signal reception unit, 130 beacon signal positioning unit, 140 satellite signal Positioning unit 150 Time management unit 160 Signal quality evaluation unit 170 Self-position estimation unit 300 Processing circuit 301 Processor 302 Storage device 304 Recording medium 305 Program 400 Position estimation device 500 Automatic operation system 510 Travel Path generation device 520 Vehicle control device 530 Actuator 531 EPS controller 532 Power train controller 533 Brake controller 535 EPS unit 536 Power train unit 537 Brake unit

Claims (12)

a satellite signal receiving unit that receives a satellite signal transmitted from a positioning satellite;
a beacon signal communication unit for receiving, by a tag node, a beacon signal transmitted from an anchor installed on the roadside;
a satellite signal positioning unit that acquires satellite positioning position information based on the satellite signal;
a beacon signal positioning unit that acquires beacon positioning position information based on the beacon signal;
a self-position estimation unit that estimates a self-position based on the beacon positioning position information and the satellite positioning position information;
a signal quality evaluation unit that generates a signal quality evaluation value for each communication state of the beacon signal and the satellite signal;
The self-location estimating unit uses the beacon positioning position information selected based on the signal quality evaluation value of the beacon signal and the satellite positioning position information selected based on the signal quality evaluation value of the satellite signal. estimating the self-position based on the signal quality evaluation unit, and generating a weighting factor for each of the beacon positioning position information and the satellite positioning position information based on the signal quality evaluation value generated by the signal quality evaluation unit. estimation device. a satellite signal receiving unit that receives a satellite signal transmitted from a positioning satellite;
a beacon signal communication unit for receiving, by a tag node, a beacon signal transmitted from an anchor installed on the roadside;
a satellite signal positioning unit that acquires satellite positioning position information based on the satellite signal;
a beacon signal positioning unit that acquires beacon positioning position information based on the beacon signal;
a self-position estimation unit that estimates a self-position based on the beacon positioning position information and the satellite positioning position information ;
a signal quality evaluation unit that generates a signal quality evaluation value for each communication state of the beacon signal and the satellite signal;
The self-location estimating unit uses the beacon positioning position information selected based on the signal quality evaluation value of the beacon signal and the satellite positioning position information selected based on the signal quality evaluation value of the satellite signal. The signal quality evaluation unit estimates the communication state of the beacon signal based on the correlation value of the pattern signal shared between the anchor and the tag node, or by the beacon signal communication unit A position estimating device, wherein said signal quality evaluation value is generated based on a beacon signal strength and a correlation value of a pattern signal shared between said anchor and said tag node. The beacon signal communication unit has an angle measurement function using a plurality of antennas installed in the tag node,
The position estimation according to claim 1 or 2, wherein the beacon signal positioning unit acquires the beacon positioning position information based on the position of the anchor, the distance to the anchor, and the direction of the beacon signal. Device. further comprising a time management unit that manages reception timing of the satellite signal transmitted from the positioning satellite;
4. The position estimation device according to any one of claims 1 to 3, wherein positioning timing of the beacon signal in the beacon signal positioning section is synchronized with reception timing of the satellite signal in the satellite signal positioning section. The position estimation device according to claim 1 , wherein the weighting factor is set relatively larger as the signal quality evaluation value is higher. 2. The position estimation device according to claim 1 , wherein said weighting factor is set based on an accuracy reduction rate of said satellite signal. When the signal quality evaluation value of the beacon signal and each of the signal quality evaluation values of the satellite signals are both less than an evaluation threshold, the self-location estimating unit uses both the beacon positioning position information and the satellite positioning position information. 7. The position estimation device according to any one of claims 1 to 6, wherein the self-position is estimated by using the position estimation device. 6. The signal quality evaluation unit according to any one of claims 1 to 5, wherein the signal quality evaluation unit generates the signal quality evaluation value based on a combination of one or both of accuracy degradation rate and satellite signal strength. Position estimator. The signal quality evaluation unit evaluates the communication state of the beacon signal based on one or both of a beacon signal strength by the beacon signal communication unit and a correlation value of pattern signals shared between the anchor and the tag node. 2. The position estimation device according to claim 1 , wherein said signal quality evaluation value is generated based on a combination. A position estimation device according to any one of claims 1 to 9 , which is mounted on the host vehicle;
A travel route generating device mounted on the own vehicle for generating a travel route from the own vehicle position to a target point by using the own vehicle position of the own vehicle output from the position estimation device. and,
A vehicle control device that is mounted on the own vehicle and sets a target trajectory and a target travel speed for executing automatic driving control of the own vehicle on the generated travel route;
automatic driving system. a satellite signal reception step of receiving a satellite signal transmitted from a positioning satellite;
a beacon signal communication step of receiving, by a tag node, a beacon signal transmitted from an anchor installed on the roadside;
a satellite signal positioning step of obtaining satellite positioning position information based on the satellite signals;
a beacon signal positioning step of obtaining beacon positioning position information based on the beacon signal;
a self-position estimation step of estimating self-position based on the beacon positioning position information and the satellite positioning position information;
a signal quality evaluation step of generating a signal quality evaluation value from communication conditions of each of the beacon signal and the satellite signal;
In the self-position estimation step, the beacon positioning position information selected based on the signal quality evaluation value of the beacon signal, and the satellite positioning position information selected based on the signal quality evaluation value of the satellite signal. estimating the self-position based on the signal quality evaluation step, and generating a weighting factor for each of the beacon positioning position information and the satellite positioning position information based on the signal quality evaluation value generated by the signal quality evaluation step. estimation method. further comprising a time management step of managing reception timing of the satellite signal transmitted from the positioning satellite;
12. The position estimation method according to claim 11 , wherein positioning timing of said beacon signal in said beacon signal positioning step is synchronized with reception timing of said satellite signal in said satellite signal positioning step.

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