JP5352492B2 - Positioning device and program - Google Patents

Description

  The present invention relates to a positioning device and a program, and more particularly to a positioning device and a program for positioning a reception position or speed based on a satellite signal from a positioning satellite.

  2. Description of the Related Art Conventionally, in GPS positioning devices, it has been attempted to improve the positioning accuracy by reducing the influence of multipath, which is a major cause of positioning errors in urban areas. For example, in a GPS receiver that receives radio waves transmitted from a plurality of satellites, an antenna that receives radio waves transmitted from each satellite and an elevation angle θn of each satellite is obtained based on the received radio waves, and the elevation angle θn is a reference elevation angle. There has been proposed a GPS receiver that selectively uses only radio waves from a satellite larger than the angle θref to measure a position (see, for example, Patent Document 1).

  In addition, position information and height information about structures such as buildings are stored, the position of the moving body is detected based on a signal from a GPS satellite, and the stored position information and height information of the structure is referred to. If there is a structure on the straight line connecting the current position of the moving object and the position of the GPS satellite, the current position of the moving object is corrected to the position obtained when the straight line is reflected from the surface of the structure. A position detection device has been proposed (see, for example, Patent Document 2).

JP 2002-277527 A JP 2005-195493 A

  However, a signal from a satellite that directly receives radio waves in a place where visibility is good even when the elevation angle is low has a small pseudo-range error and can be used for positioning. There is a problem that the satellite cannot be selected properly because the selection of the satellite is determined only by the elevation angle without considering the influence of the building environment. In addition, the technique described in Patent Document 1 has a problem that the pseudorange error cannot be corrected because the pseudorange error is not obtained.

  Further, the technique described in Patent Document 2 described above has a problem that it is necessary to hold the latest building information in detail and high accuracy, and it is difficult to apply it to an inexpensive apparatus. In addition, since the positioning result is corrected instead of the pseudorange, there is a problem that the influence of the multipath of each satellite signal is not taken into consideration and the position cannot be corrected accurately.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a positioning device and a program capable of obtaining a highly reliable positioning result considering the influence of multipath by a simple method. And

  In order to achieve the above object, a positioning apparatus of a first invention receives satellite signals transmitted from a plurality of different positioning satellites, and simulates each of the positioning satellites from each of the positioning satellites to a reception position based on the received satellite signals. Based on the pseudo distance measured by the GPS receiver that measures the distance, the first positioning means that measures the reception position and the building height acquisition that acquires the building height information related to the height of the building around the reception position And the height indicated by the building height information is the highest reflection position due to the multipath of the satellite signal, the distance from the positioning satellite, and the satellite elevation angle measured by the GPS receiver. Based on the pseudorange error calculation means for calculating the range of the pseudorange error of each of the plurality of positioning satellites, and the pseudorange of each of the plurality of positioning satellites calculated by the pseudorange error calculation means Using the pseudo-range error contained in the error range, is configured to include a, a second positioning means for positioning the receiving position.

  According to the positioning apparatus of the first invention, the first positioning means receives satellite signals transmitted from a plurality of different positioning satellites, and simulates from each of the positioning satellites to the reception position based on the received satellite signals. The reception position is measured based on the pseudorange measured by the GPS receiver that measures the distance. Further, the building height acquisition means acquires building height information related to the height of the building around the reception position. The building height information related to the height of the building includes an average value, a maximum value, a median value, and the like of the heights of the buildings existing around the reception position.

  Then, assuming that the height indicated by the building height information is the highest reflection position due to the multipath of the satellite signal, the pseudo-range error calculation means calculates the building height information, the distance from the positioning satellite, and the satellite measured by the GPS receiver. Based on the elevation angle, the range of the pseudorange error of each of the plurality of positioning satellites is calculated. Assuming that the height indicated by the building height information is the highest reflection position by the multipath, the calculated pseudorange error becomes the maximum value. That is, the range of the pseudo distance error can be calculated as being less than or equal to this maximum value. Since it can be determined that the larger the pseudorange error calculated here is, the greater the influence of multipath is, the range of the pseudorange error can be used as an index indicating the reliability of positioning accuracy. Therefore, the second positioning means measures the reception position using the pseudo distance error included in the range of the pseudo distance error of each of the plurality of positioning satellites calculated by the pseudo distance error calculating means.

  In this way, the range of the pseudorange error calculated based on the building height information, the distance to the positioning satellite, and the satellite elevation angle is used as an index indicating the reliability of the positioning accuracy. A highly reliable positioning result can be obtained.

Also, either the first invention, the second positioning means positioning the received position to select the pseudo distance of the pseudo-range error calculating pseudo distance error range is small positioning satellites calculated by means Alternatively, each of the pseudo distances can be weighted according to the range of the pseudo distance error calculated by the pseudo distance error calculating means, thereby positioning the reception position.

  The positioning device of the second invention receives GPS signals transmitted from a plurality of different positioning satellites, and measures the Doppler shift of the satellite signals from each of the positioning satellites based on the received satellite signals. Based on the Doppler shift measured by a machine, first speed estimation means for estimating the speed of the GPS receiver and building height information related to the height of the building around the reception position where the satellite signal is received are acquired. Assuming that the height indicated by the building height acquisition means and the height of the building is the highest reflection position by the multipath of the satellite signal, the building height information, the distance to the positioning satellite, the speed of the GPS receiver, and the A Doppler shift error calculating means for calculating a range of Doppler shift error for each of the plurality of positioning satellites based on a satellite elevation angle measured by a GPS receiver; and the Doppler Second speed estimating means for estimating the speed of the GPS receiver using a Doppler shift error included in a range of Doppler shift errors of each of the plurality of positioning satellites calculated by the shift error calculating means. It consists of

  According to the positioning apparatus of the second invention, the first velocity estimating means receives satellite signals transmitted from a plurality of different positioning satellites, and based on the received satellite signals, the satellite signals from each of the positioning satellites are received. Based on the Doppler shift measured by the GPS receiver that measures the Doppler shift, the GPS receiver speed is estimated, and the building height information relating to the height of the building around the reception position where the building height acquisition means has received the satellite signal is obtained. And the Doppler shift error calculating means assumes the height indicated by the building height information as the highest reflection position due to the multipath of the satellite signal, the building height information, the distance to the positioning satellite, the speed of the GPS receiver, and Based on the satellite elevation angle measured by the GPS receiver, the range of the Doppler shift error of each of the plurality of positioning satellites is calculated, and the second speed estimation means serves as the Doppler shift error calculation means. Using Doppler shift error contained in the range of the Doppler shift error of each of the plurality of positioning satellites that have been calculated I, to estimate the velocity of the GPS receiver.

  The speed of the GPS receiver used when calculating the Doppler shift error range may be the speed estimated by the first speed estimating means, or the speed of the moving object detected by the inertial navigation device. May be obtained and used.

  In this way, the range of Doppler shift error calculated based on building height information, GPS receiver speed, and satellite elevation angle is used as an index indicating the reliability of positioning accuracy. A highly reliable positioning result can be obtained.

In the second invention, the second speed estimation means, the speed of the Doppler shift error calculation means and said GPS receiver selects the Doppler shift range is small positioning satellites calculated Doppler shift error by It is possible to estimate the speed of the GPS receiver by weighting each of the Doppler shifts according to the range of the Doppler shift error calculated by the Doppler shift error calculation means. .

In the first and second aspects of the present invention, the building height acquisition means may store the building height information for pre Me longitude and latitude, the building height information corresponding to the received position from stored building height information Can be acquired.

  In the positioning program of the third invention, the computer receives satellite signals transmitted from a plurality of different positioning satellites, and measures a pseudo distance from each of the positioning satellites to the reception position based on the received satellite signals. First positioning means for positioning the reception position based on the pseudo distance measured by the GPS receiver, building height acquisition means for acquiring building height information relating to the height of the building around the reception position, and the building Assuming that the height indicated by the high information is the highest reflection position due to the multipath of the satellite signal, based on the building height information, the distance to the positioning satellite, and the satellite elevation angle measured by the GPS receiver, A pseudorange error calculating means for calculating a range of pseudorange errors of each of the plurality of positioning satellites, and a pseudorange of each of the plurality of positioning satellites calculated by the pseudorange error calculating means; Using pseudorange error included in the error range, is a program for functioning as a second positioning means for positioning the receiving position.

  In the positioning program of the fourth invention, the computer receives satellite signals transmitted from a plurality of different positioning satellites, and measures the Doppler shift of the satellite signals from each of the positioning satellites based on the received satellite signals. First height estimating means for estimating the speed of the GPS receiver based on the Doppler shift measured by the GPS receiver, and building height information relating to the height of the building around the receiving position where the satellite signal is received. Building height acquisition means to acquire, assuming the height indicated by the building height information as the highest reflection position by the multipath of the satellite signal, the building height information, the distance to the positioning satellite, the speed of the GPS receiver, and Based on the satellite elevation angle measured by the GPS receiver, a Doppler shift error calculation method for calculating a range of Doppler shift error for each of the plurality of positioning satellites. And second speed estimating means for estimating the speed of the GPS receiver using Doppler shift error included in the range of Doppler shift error of each of the plurality of positioning satellites calculated by the Doppler shift error calculating means. It is a program to make it function as.

  The storage medium for storing the program of the present invention is not particularly limited, and may be a hard disk or a ROM. Further, it may be a CD-ROM, a DVD disk, a magneto-optical disk or an IC card. Furthermore, the program may be downloaded from a server or the like connected to the network.

  As described above, according to the positioning apparatus and program of the present invention, the building height information, the distance to the positioning satellite, and the range of the pseudorange error calculated based on the satellite elevation angle, or the building height information, the GPS receiver Because the Doppler shift error range calculated based on the speed of the satellite and the satellite elevation angle is used as an index indicating the reliability of positioning accuracy, a highly reliable positioning result that takes into account the effects of multipaths can be obtained with a simple method. The effect that it can be obtained.

It is a block diagram which shows the vehicle-mounted positioning apparatus which concerns on this Embodiment. It is a figure for demonstrating reflection of the satellite signal by a building. It is a figure for demonstrating the principle of calculation of a pseudo distance error. It is a figure for demonstrating the principle of calculation of a Doppler shift error. It is a flowchart which shows the content of the positioning process routine in the computer of the vehicle-mounted positioning apparatus which concerns on this Embodiment. It is a figure which shows an example of the pseudo distance error estimation result by the vehicle-mounted positioning apparatus which concerns on this Embodiment, and actual pseudo distance error data. It is a figure which shows an example of the Doppler shift error estimation result by the vehicle-mounted positioning apparatus which concerns on this Embodiment, and actual Doppler shift error data. It is a figure which shows the relationship between the delay of an indirect wave, and a pseudorange error. It is a figure which shows an example of the pseudo distance error estimation result by a correlator model.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the case where this invention is applied to the vehicle-mounted positioning apparatus which mounts in a vehicle and measures a receiving position (position of the own vehicle) is demonstrated to an example.

  As shown in FIG. 1, the on-vehicle positioning device 10 according to the present embodiment is based on a GPS receiver 12 that receives radio waves from a positioning satellite and outputs satellite signal information, and an output from the GPS receiver 12. And a computer 14 that performs positioning of the reception position and estimation of the speed.

  The GPS receiver 12 receives a satellite signal transmitted from a positioning satellite, and based on the satellite signals transmitted from all the positioning satellites received by the receiving unit 18, the positioning satellite and the reception position Pseudo distance between them (the propagation distance of the signal received from each positioning satellite) is calculated, and the pseudo distance calculation section 20 that outputs the calculated pseudo distance to the computer 14 and the transmission from all the positioning satellites received by the receiving section 18 Orbital information is acquired based on satellite signals transmitted from all positioning satellites received by the receiving unit 18 and a Doppler calculating unit 22 that calculates the Doppler shift frequency of the satellite signal based on the received satellite signals. And a satellite elevation angle calculation unit 24 that calculates the satellite positions and calculates the elevation angles of all the satellite positions at the reception position. Further, the GPS receiver 12 is further configured as GPS satellite information based on the satellite signals transmitted from all the positioning satellites received by the receiving unit 18, and further includes the satellite number, carrier wave phase, signal intensity, etc. of the GPS satellite. Is output to the computer 14.

  The computer 14 includes a storage device such as a CPU, a ROM that stores a program for realizing a positioning processing routine described later, a RAM that temporarily stores data, and an HDD.

  When the computer 14 is represented by functional blocks according to the positioning processing routine described below, the position coordinates and velocity of the reception position are calculated based on the pseudorange and the Doppler shift frequency output from the GPS receiver 12, as shown in FIG. Based on the calculated position coordinates and building height information, the building height information around the reception position is obtained based on the positioning calculation unit 26 that calculates, the building height information storage unit 28 that stores the building height information corresponding to the latitude and longitude. Based on the building height information acquisition unit 30 and the satellite elevation angle output from the GPS receiver 12, the acquired building height information, the calculated position coordinates and the velocity, the range of the pseudorange error and the range of the Doppler shift error are determined. The observation error calculation unit 34 to be calculated, the pseudo distance and the Doppler shift frequency output from the GPS receiver 12, and the observation error calculation unit 34 Based on the range and scope of the Doppler shift error of the calculated pseudo-range error I, and a error correction positioning computation unit 36 for calculating the position coordinates and velocity of the receiver position correcting errors.

  The positioning calculation unit 26 uses the Newton-Raphson method described below for each combination of four or more positioning satellites that have received satellite signals from the pseudorange and satellite position output from the GPS receiver 12. Calculate coordinates.

First, the pseudo distance R _i of the satellite i is the position coordinate of the satellite i (x _i , y _i , z _i ), and the initial value of the estimated position coordinate of the GPS receiver 12 is (x ₀ , y ₀ , z ₀ ). The true position coordinate of the GPS receiver 12 to be obtained is (x _p , y _p , z _p ), the initial value of the estimated clock bias of the GPS receiver 12 is B ₀ , and the clock bias (clock error) of the satellite i is b _{If i} , it can be expressed as in equation (1).

  If the difference between the true position coordinate of the GPS receiver 12 and the estimated value is Δ, equation (2) is obtained.

  When the above equation (1) is linearized by equation (2), equation (3) is obtained.

  When equation (3) is written down in matrix representation for all satellites, equation (4) is obtained, and when equation (5) is further replaced, equation (6) is obtained.

  Here, A is a geometric matrix characterizing the satellite arrangement, and ΔR is a vector notation of the pseudorange Ri of the i-th positioning satellite corrected for ionospheric delay, tropospheric delay, and satellite clock bias.

  Here, when m> 4, the number of equations increases with respect to the number of variables to be obtained, resulting in an overdetermined state. Therefore, the least square method is used to obey the constraints of m equations as much as possible. Find a solution. This can be obtained by the equation shown by the equation (7).

  The position coordinate of the reception position and the clock bias B can be calculated by updating the expression (2) using ΔX obtained from the expression (7) and repeatedly calculating until the estimated value converges.

  The positioning calculation unit 26, for example, for each of the combinations of all n positioning satellites that have received satellite signals, and all the combinations (n combinations) of n−1 positioning satellites excluding one positioning satellite. The position coordinates of the reception position are calculated by the optimum estimation using the least square method described above.

In addition, the positioning calculation unit 26 removes, from the Doppler shift frequency and the satellite position output from the GPS receiver 12, for example, a combination of all n positioning satellites that have received satellite signals, and n− except for one positioning satellite. For each of all combinations (n combinations) of one positioning satellite, the speed of the GPS receiver 12 (the speed of the own vehicle) and the clock are obtained by the optimum estimation using the least square method as in the above positioning calculation. A vector v (= (v _x , v _y , v _h , D)) representing the drift is calculated. However, v _x is the longitude direction of the velocity, v _y is the speed of latitudinal, v _h the altitude direction of the velocity, D is a clock drift. For the calculation of the speed and clock drift, the optimum estimation described in non-patent literature (Takayasu Sakai, “Practical programming for GPS”, Tokyo Denki University Press, 2007.) may be used. The detailed explanation is omitted.

  The building height information storage unit 28 stores building height information corresponding to the latitude and longitude. When the latitude and longitude (x, y) are input, the following equation (8) is output to output the building height information h. It behaves as a function represented by Note that the building height information includes an average value, a maximum value, a median value, and the like of the heights of buildings around the corresponding latitude and longitude.

      h = f (x, y) (8)

  The observation error calculation unit 34 calculates the pseudorange error range and the Doppler shift error range based on the satellite elevation angle output from the GPS receiver 12, the acquired building height information, the calculated position coordinates, and the velocity. .

  Here, the principle of calculating the range of the pseudorange error in the present embodiment will be described.

  As shown in FIG. 2, a satellite signal from a positioning satellite having a low elevation angle is reflected by a building such as a building and reaches the GPS receiver 12, which causes a pseudo-range error due to a large multipath. On the other hand, even if a satellite signal from a positioning satellite with a high elevation angle is reflected on a building such as a building, the reflection angle is large, so there is a high possibility that the satellite signal will reach the ground before reaching the GPS receiver 12, and a multipath simulation is performed. Less prone to distance errors. Therefore, it is possible to predict the degree of pseudorange error due to multipath based on the information on the elevation angle of the satellite and the information on the height of a building such as a building around the reception position.

  As shown in FIG. 3, when it is assumed that the satellite signal from the positioning satellite is reflected at the highest point of the building with the building height h and reaches the GPS receiver 12, a difference occurs in the propagation path of the reflected wave and the direct wave. This is the main cause of multipath. Here, since it is difficult to know at which height the satellite signal is actually reflected, a case where the building height h is the highest point of the building will be described for the reason described later. First, the incident angle φ at the reflection point is calculated by the following equation (9).

  Here, d is the distance between the GPS receiver 12 and the positioning satellite obtained using the position coordinates calculated by the positioning calculator 26, the pseudo distance output from the pseudo distance calculator 20 of the GPS receiver 12, or It is a fixed value determined, θ is the satellite elevation angle of the positioning satellite, and l is the reachable distance in the horizontal direction from the building of the reflected wave reflected by the building.

  On the other hand, the reflection angle φ is calculated by the following equation (10).

  When φ is deleted from the equations (9) and (10), the reachable distance l is calculated by the following equation (11).

Thus, when the distance d to the positioning satellite, the satellite elevation angle θ, and the reflection point (building height h) are determined, the reachable distance l of the reflected wave is uniquely determined, and the reflection angle φ is also uniquely determined. The pseudo-range error e _ρ due to multipath, that is, the difference in propagation path length between the reflected wave and the direct wave is also uniquely determined by the following equation (12).

Although the case where the satellite signal is reflected at the highest point of the building has been described here, an average value, a median value, or the like of the height of the building around the reception position may be used. However, as can be seen from the equations (10) to (12), the higher the building height h assumed as the multipath reflection position, the higher the reflection point and the easier the reflected wave reaches the GPS receiver 12. Even if it is difficult to know the actual reflection position, at least the reflection point will not be higher than the height of the building. The pseudo-range error is maximized when the satellite signal is reflected at the highest point of the building and reaches the GPS receiver 12. Therefore, when the upper limit of the pseudo-range error is determined by the height of the building and the satellite elevation angle. I can say that. That is, assuming that the building height h is the highest point of the building, the pseudorange error e _ρ calculated by the equation (12) is the maximum value of the pseudorange error. It can be calculated as follows. Therefore, if the calculation is performed using the maximum value of the buildings around the reception position, the pseudo-range error is also maximized, so that the reliability of positioning accuracy can be determined more strictly.

The observation error calculation unit 34 obtains or acquires the distance d to the positioning satellite according to the above principle, and outputs the distance d, the building height information h acquired by the building height information acquisition unit 30, and the GPS receiver 12. Based on the satellite elevation angle θ, the reachable distance l is obtained by the equation (11), and the reflection angle φ is obtained by the equation (10) based on the obtained reachable distance l and the building height information h. Then, based on the distance d, the satellite elevation angle θ, and the reflection angle φ, the pseudorange error e _ρ is calculated by the equation (12).

  Next, the principle of calculating the Doppler shift error range in the present embodiment will be described.

  As shown in FIG. 4, assuming that the satellite signal from the positioning satellite is reflected at the height h on the building surface and reaches the GPS receiver 12, the satellite direction component Δv of the vehicle speed is expressed by the following equation (13). Calculated by

The reflected wave direction component Δv _rfl of the vehicle speed is calculated by the following equation (14).

(13) from the equation and the equation (14), the Doppler shift error e _d by multipath, equal to the before and after the reflection of the relative vehicle speed change amount for the satellite signal, is calculated by the following equation (15). Unlike the case of the pseudorange error, the Doppler shift error is less affected by the building height h.

Note that, assuming a building height h between the highest point of the building, the Doppler shift error e _d calculated by equation (15), since the maximum value of the Doppler shift error, the maximum value range of the Doppler shift error It can be calculated as follows.

The observation error calculation unit 34 obtains or acquires the distance d to the positioning satellite according to the above principle, and outputs the distance d, the building height information h acquired by the building height information acquisition unit 30, and the GPS receiver 12. Based on the satellite elevation angle θ, the reachable distance l is obtained by the equation (11), and the reflection angle φ is obtained by the equation (10) based on the obtained reachable distance l and the building height information h. Then, based on the velocity v of the GPS receiver 12 calculated by the positioning calculation unit 26, the satellite elevation angle θ, and the reflection angle φ, the Doppler shift error _ed is calculated by Equation (15). Note that the speed of the host vehicle detected by the inertial navigation device 40 may be acquired and used as the speed v.

The error correction positioning calculation unit 36 calculates the position coordinates of the reception position where the error is corrected, using the pseudoranges of all the positioning satellites that have received the satellite signals and the pseudorange error e _ρ obtained by the observation error calculation unit 34. To do. For example, a weighting matrix is defined as in the following expression (16), and the error is corrected by the weighted least square method according to the following expression (17) in which the weighting matrix is applied to the above expression (7). Calculate position coordinates.

Here, e _ρi is a pseudorange error of the i-th satellite, and W is a weight matrix whose (i, i) component is w _ii .

The error correction positioning operation unit 36, a Doppler shift frequency of all positioning satellites receive the satellite signal, with the Doppler shift error e _d obtained in observation error calculating unit 34, GPS receiver to correct the error 12 Calculate the speed of. For example, similarly to the above (16), to define the weight matrix determined from the Doppler shift error e _d, by weighted least squares method, calculates the speed of the GPS receiver 12 with the corrected errors.

If the pseudorange error e _ρ is large, the weight matrix W expressed by the above equation (16) may be applied to the speed calculation, assuming that the Doppler shift error _ed is also large.

Further, since the pseudorange error e _ρ and the Doppler shift error _ed are maximum values of the pseudorange error range and the Doppler shift error range, the pseudorange error e _ρ and the Doppler shift error _ed are each given a coefficient k ( A value obtained by multiplying 0 <k ≦ 1) may be used as a pseudorange error and a Doppler shift error for error correction.

  The error correction positioning calculation unit 36 outputs the calculated position coordinates of the reception position and the speed of the GPS receiver 12 to an external device (for example, a positioning result display device, a vehicle control device, a sensor integration device, etc.).

  Next, the operation of the in-vehicle positioning device 10 according to the present embodiment will be described.

  When the receiving unit 18 of the GPS receiver 12 receives radio waves from a plurality of positioning satellites, the computer 14 repeatedly executes the positioning processing routine shown in FIG.

  First, in step 100, information on a plurality of positioning satellites (pseudorange, Doppler shift frequency, satellite elevation angle, etc.) output from the GPS receiver 12 is acquired.

  Next, in step 102, the position coordinates (longitude and latitude) of the reception position are calculated using four or more of the pseudo distances acquired in step 100, and based on the Doppler shift frequency acquired in step 100. Then, the speed of the GPS receiver 12 is calculated.

  Next, in step 104, building height information corresponding to the position coordinates of the reception position calculated in step 102 is acquired from the building height information storage unit 28.

Next, in step 106, the distance d between the GPS receiver 12 and the positioning satellite is obtained from the position coordinates calculated in step 102, the obtained distance d, the building height information h obtained in step 104, and the above Based on the satellite elevation angle θ acquired in step 100, the reachable distance l is obtained by the equation (11), and the reflection angle φ is obtained by the equation (10) based on the obtained reachable distance l and the building height information h. Ask. Then, based on the distance d, the satellite elevation angle θ, and the reflection angle φ, the pseudorange error e _ρ is calculated by the equation (12).

Next, in step 108, the distance d between the GPS receiver 12 and the positioning satellite is obtained from the position coordinates calculated in step 102, the obtained distance d, the building height information h obtained in step 104, and the above Based on the satellite elevation angle θ acquired in step 100, the reachable distance l is obtained by the equation (11), and the reflection angle φ is obtained by the equation (10) based on the obtained reachable distance l and the building height information h. Ask. Then, based on the velocity v of the GPS receiver 12 calculated in step 102, the satellite elevation angle θ, and the reflection angle φ, the Doppler shift error _ed is calculated by the equation (15).

  In steps 106 and 108, the pseudo distance output from the pseudo distance calculator 20 of the GPS receiver 12 or a predetermined fixed value may be used as the distance d. In step 108, the vehicle speed detected by the inertial navigation device 40 may be used as the speed v.

Next, in step 110, the reception position is calculated based on the pseudo distance acquired in step 100 and the pseudo distance error e _ρ calculated in step 106, and the Doppler acquired in step 100 is calculated. and shift frequency, based on the Doppler shift error e _d calculated in step 108, and calculates the speed of the GPS receiver 12, and terminates the positioning process routine.

  FIG. 6 shows actual pseudorange error data (black dots in the figure) and pseudorange errors (estimated values) calculated by the in-vehicle positioning device 10 of the present embodiment. As a parameter value, d = 2.24e7 is shown. In the figure, an estimated value of h = 100 is indicated by a solid line, and an estimated value of h = 50 is indicated by a broken line. From this result, it can be seen that the hypothesis that the reflected wave is less likely to reach the GPS receiver 12 and the pseudorange error is less likely to occur as the satellite elevation angle increases, and the tendency of the actual pseudorange error data agrees well. Recognize. Further, the higher the building height information h, that is, the higher the reflection point, the easier it is for the reflected wave to reach the GPS receiver 12, and thus the error value of the estimated value increases. The maximum value of the reflection point height is the maximum value of the buildings around the reception position, and it can be said that the upper limit of the pseudorange error is determined by this height. The pseudo distance error calculated in the present embodiment reproduces the upper limit of the generated pseudo distance error by inputting the height of the highest building around the reception position.

  FIG. 7 shows actual Doppler shift error data (black dots in the figure) and Doppler shift errors (estimated values) calculated by the in-vehicle positioning device 10 of the present embodiment. As a parameter value, d = 2.24e7 is shown. In the figure, an estimated value of v = 40 is indicated by a solid line, and an estimated value of v = 60 is indicated by a broken line. From this result, it can be seen that, as in the case of the pseudorange error, the tendency that the error decreases as the elevation angle increases is well reproduced. However, in the case of the Doppler shift error, unlike the case of the pseudo-range error, the reflected wave does not easily reach the GPS receiver 12 and thus an error does not occur. Since it does not change so much between the reflected wave and the direct wave, it is considered that errors are unlikely to occur. Further, as the vehicle speed v increases, the influence of the relative speed change due to reflection increases, so the value of the generated Doppler shift error also increases. That is, the Doppler shift error calculated in the present embodiment can be estimated by inputting the speed of the GPS receiver 12, and the upper and lower limits of the generated Doppler shift error can be estimated. Show.

  As described above, according to the vehicle-mounted positioning device according to the present embodiment, the building height information related to the height of the reception position, the distance from the positioning satellite, and the pseudo-range error calculated based on the satellite elevation angle, or the building Since the Doppler shift error calculated based on the high information, GPS receiver speed, and satellite elevation angle is used as an index indicating the reliability of positioning accuracy, the details, high accuracy, and the latest building information around the receiving position are used. There is no need to hold it, and it is possible to obtain a highly reliable positioning result in consideration of the influence of multipaths by a simple method.

  In the above-described embodiment, the case where the corrected position coordinates and velocity are calculated using the weight matrix using the calculated pseudorange error or Doppler shift error has been described. However, the calculated pseudorange error or Doppler shift is calculated. Positioning satellites with small errors, for example, four positioning satellites in order of increasing pseudorange error or Doppler shift error, are selected, and position coordinates and velocity are calculated using satellite signals transmitted from the selected positioning satellites. May be.

  In the above-described embodiment, the case where both the pseudorange error and the Doppler shift error are calculated and the error-corrected position coordinates and velocity are calculated is described. However, the present invention is not limited to this. Only the position coordinate corrected by error may be calculated, or only the Doppler shift error may be calculated and only the speed corrected by error may be calculated.

  Various arithmetic processes may be performed using GPS radio wave propagation time instead of pseudorange data.

  In addition, the pseudorange error described in the above embodiment is a value that is generated when only the indirect wave reflected by the building is received without receiving the direct wave from the positioning satellite. When both a direct wave and an indirect wave are received, the output pseudorange error value depends on the operation of the correlator. The indirect wave delay δ with respect to the direct wave corresponds to the pseudorange error described in the present embodiment. When the SMR (indirect wave / direct wave amplitude ratio) and the correlator width w are determined, the pseudorange error when both the direct wave and the indirect wave are received is calculated by the following equation (18). Where T is the chip width.

  FIG. 8 shows the relationship between the delay of the indirect wave with respect to the direct wave when SMR = 0.5 and the output pseudorange error. In the present embodiment, by inputting the height of the highest building around the reception position, the upper limit of the generated pseudorange error can be estimated, but the lower limit cannot be estimated. It is this correlator model that covers this. FIG. 9 shows the result of the lower limit error estimation using the correlator model. The parameter values are d = 2.24e7, h = 100, SMR = 0.5, and w = 1. The pseudorange error due to multipath takes almost a positive value and rarely takes a negative value, but the tendency is well reproduced.

DESCRIPTION OF SYMBOLS 10 In-vehicle positioning apparatus 12 GPS receiver 14 Computer 18 Reception part 20 Pseudo distance calculation part 22 Doppler calculation part 24 Satellite elevation angle calculation part 26 Positioning calculation part 28 Building height information storage part 30 Building height information acquisition part 34 Observation error calculation part 36 Error Corrected positioning calculation unit 40 Inertial navigation device

Claims (8)

Based on the pseudo distance measured by a GPS receiver that receives satellite signals transmitted from a plurality of different positioning satellites and measures a pseudo distance from each of the positioning satellites to a reception position based on the received satellite signals. First positioning means for positioning the reception position;
Building height acquisition means for acquiring building height information relating to the height of the building around the reception position;
Assuming that the height indicated by the building height information is the highest reflection position by the multipath of the satellite signal, based on the building height information, the distance from the positioning satellite, and the satellite elevation angle measured by the GPS receiver. Pseudo range error calculation means for calculating a range of pseudo range error of each of the plurality of positioning satellites;
Second positioning means for positioning the reception position using a pseudorange error included in a pseudorange error range of each of the plurality of positioning satellites calculated by the pseudorange error calculation means;
Positioning device including. Said second positioning means, the pseudo-range or ranges of pseudo-range error calculated by the error calculation means selects a pseudorange small positioning satellites positioning the receiving position, or to each of the pseudorange The positioning device according to claim 1, wherein the receiving position is measured by performing weighting according to a range of the pseudo distance error calculated by the pseudo distance error calculating means. Based on the Doppler shift measured by a GPS receiver that receives satellite signals transmitted from a plurality of different positioning satellites and measures the Doppler shift of the satellite signals from each of the positioning satellites based on the received satellite signals. First speed estimating means for estimating the speed of the GPS receiver;
Building height acquisition means for acquiring building height information relating to the height of the building around the reception position that received the satellite signal;
Assuming that the height indicated by the building height information is the highest reflection position by the multipath of the satellite signal, the building height information, the distance to the positioning satellite, the speed of the GPS receiver, and the GPS receiver are measured. A Doppler shift error calculating means for calculating a range of Doppler shift error for each of the plurality of positioning satellites based on the satellite elevation angle;
Second speed estimating means for estimating the speed of the GPS receiver using a Doppler shift error included in a range of Doppler shift errors of each of the plurality of positioning satellites calculated by the Doppler shift error calculating means;
Positioning device including. The second speed estimation section, the Doppler shift or error calculating unit range of the Doppler shift error calculated by selects a Doppler shift of the small positioning satellite positions the speed of the GPS receiver, or the Doppler 4. The positioning device according to claim 3, wherein each of the shifts is weighted in accordance with a range of Doppler shift error calculated by the Doppler shift error calculating means to estimate the speed of the GPS receiver. The building height acquisition means may store the building height information for pre Me longitude and latitude, one from the stored building height information of claims 1 to 4 for obtaining a building height information corresponding to the received position A positioning device according to claim 1. Computer
Based on the pseudo distance measured by a GPS receiver that receives satellite signals transmitted from a plurality of different positioning satellites and measures a pseudo distance from each of the positioning satellites to a reception position based on the received satellite signals. , First positioning means for positioning the reception position;
Building height acquisition means for acquiring building height information related to the height of the building around the reception position;
Assuming that the height indicated by the building height information is the highest reflection position by the multipath of the satellite signal, based on the building height information, the distance from the positioning satellite, and the satellite elevation angle measured by the GPS receiver. A pseudo-range error calculating unit that calculates a range of pseudo-range errors of each of the plurality of positioning satellites, and a pseudo-range error range of each of the plurality of positioning satellites calculated by the pseudo-range error calculating unit. A positioning program for functioning as a second positioning means for positioning the reception position using a pseudo-range error. Computer
Based on the Doppler shift measured by a GPS receiver that receives satellite signals transmitted from a plurality of different positioning satellites and measures the Doppler shift of the satellite signals from each of the positioning satellites based on the received satellite signals. First speed estimation means for estimating the speed of the GPS receiver;
Building height acquisition means for acquiring building height information related to the height of the building around the reception position that received the satellite signal;
Assuming that the height indicated by the building height information is the highest reflection position by the multipath of the satellite signal, the building height information, the distance to the positioning satellite, the speed of the GPS receiver, and the GPS receiver are measured. A Doppler shift error calculating means for calculating a range of Doppler shift error for each of the plurality of positioning satellites based on the satellite elevation angle; and a Doppler shift for each of the plurality of positioning satellites calculated by the Doppler shift error calculating means. A positioning program for functioning as second speed estimation means for estimating the speed of the GPS receiver using a Doppler shift error included in the error range.   The positioning program for functioning a computer as each means which comprises the positioning apparatus of any one of Claims 1-5.

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