JP2008032408A - Vehicle position correcting device, and vehicle position correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle position correcting device and a vehicle position correction method, capable of reducing longitudinal distance errors (longitudinal shifts), and capable of preventing abrupt positional jump from being generated, by map-matching processing. <P>SOLUTION: A normal is drawn from a GPS measured position onto a straight line, extending along the vehicular azimuth direction from a measured position by self-contained navigation, to calculate the distance D that connects the self-contained navigation measured position and the foot of the normal, when correcting a vehicle position, by using the measured position of a vehicle measured by the self-contained navigation and the measured position of the vehicle measured by a GPS measuring method. Then, the self-contained navigation measured position is shifted along the vehicular azimuth direction by a prescribed ratio of the distance D, the position obtained is defined as the vehicle position, and the vehicle position is map-matched on road link. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle position correction apparatus and a vehicle position correction method, and more particularly to a vehicle position correction apparatus that corrects a vehicle position using a vehicle measurement position measured by a self-contained navigation method and a vehicle measurement position measured by a GPS measurement method. And a vehicle position correction method.

The navigation system reads out map data corresponding to the current position of the vehicle from a map data storage unit such as a DVD or a hard disk HDD, draws it on the display screen, and moves the vehicle position mark on the map according to the running, Alternatively, the vehicle position mark is fixedly displayed at a certain position on the display screen (for example, the center position of the display screen), and the map is scroll-displayed.
Map data includes (1) a road layer consisting of node data, road link data, intersection data, etc., (2) a background layer for displaying objects on the map, and (3) a name of the city, town, and village. A map image composed of the character layer and the like and displayed on the display screen is generated based on the background layer and the character layer, and map matching processing and guidance route search processing are performed based on the road layer.

  In such a navigation system, it is essential to measure the current position of the vehicle. For this reason, a measurement method (self-contained navigation) that measures a vehicle position using a self-contained navigation sensor and a GPS measurement method (satellite navigation) using a GPS (Global Positioning System) satellite are used together. Usually, the position and direction of the vehicle are measured by self-contained navigation, and the vehicle position is corrected on the road link by map matching processing when the vehicle deviates from the road link. Then, when the measurement position by the self-contained navigation is more than the set distance from the GPS measurement position due to accumulation of errors, the vehicle position is corrected based on the GPS measurement position. Thereafter, again, the position and direction of the vehicle are measured by self-contained navigation, and at the same time, the map matching process is started to correct the vehicle position on the traveling road link.

In the self-contained navigation, the vehicle position is estimated as follows based on the outputs of the distance sensor and the relative orientation sensor (gyro) (see Patent Document 1). FIG. 8 is an explanatory view of a conventional vehicle position estimation method based on self-contained navigation. The distance sensor outputs a pulse every time the vehicle travels a predetermined distance, and therefore the vehicle moves by counting the number of pulses generated per unit time. Speed V can be measured. Further, the reference azimuth (θ = 0) is the positive direction of the X axis, and the counterclockwise direction from the reference azimuth is the + direction. If the previous vehicle position is point P0 (X0, Y0), the absolute azimuth in the vehicle traveling direction at point P0 is θ0, and the output of the relative azimuth sensor when moving the distance L0 is Δθ1, the change in the vehicle position Is
ΔX = L0 · cos (θ0 + Δθ1)
ΔY = L0 · sin (θ0 + Δθ1)
The estimated direction θ1 of the vehicle traveling direction and the estimated vehicle position (X1, Y1) at the current point P1 are
θ1 = θ0 + Δθ1 (1)
X1 = X0 + ΔX = X0 + L0 · cosθ1 (2)
Y1 = Y0 + ΔY = Y0 + L0 · sinθ1 (3)
Can be calculated by vector synthesis. Therefore, if the absolute azimuth and position coordinates of the vehicle at the start point are given by GPS, the vehicle position can be determined in real time by repeating the calculations of equations (1) to (3) every time the vehicle travels a predetermined distance L0 thereafter. Can be detected (estimated).

However, in self-contained navigation, errors accumulate as the vehicle travels, and the estimated vehicle position deviates from the road. Therefore, the estimated vehicle position is collated with the road data and corrected on the road link by map matching processing.
FIG. 9 is an explanatory diagram of map matching by the projection method. It is assumed that the current vehicle position is at a point Pi-1 (Xi-1, Yi-1) and the vehicle direction is θi-1 (in the figure, the point Pi-1 does not coincide with the road RDa). If the relative azimuth when traveling a distance L0 from the point Pi-1 is Δθi, the estimated vehicle position Pi ′ (Xi ′, Yi ′) by self-contained navigation and the estimated vehicle azimuth θi at Pi ′ are expressed by the following equation: θi = θi-1 + Δθi
Xi ′ = Xi−1 + L0 · cos θi
Yi ′ = Yi−1 + L0 · sinθi
Is required.

At this time, (a) a link (element constituting a road) that is included in a 200 m square with the estimated vehicle position Pi ′ as the center and that can be lowered, and the estimated vehicle direction at the estimated vehicle position Pi ′ A search is made for the angle formed by θi and the link within a certain value (for example, within 450), and the length of the perpendicular dropped from the estimated vehicle position Pi ′ to the link within a certain distance (for example, 100 m). Here, the link LKa1 (straight line connecting the nodes Na0 and Na1) on the road RDa and the link LKb1 (straight line connecting the nodes Nb0 and Nb1) on the road RDb are the corresponding links.
Next, (b) the lengths of the perpendicular lines RLia and RLib dropped from the estimated vehicle position Pi ′ to the links LKa1 and LKb1 are obtained.
(c) After that, the projection correlation value Z is expressed by the following equation: Z = dL · k1 + dθ · k2 + Dgps · k3 (4)
Calculate by dL is the length of the vertical line dropped from the estimated autonomous vehicle position Pi ′ to the link, dθ is the angle formed by the estimated vehicle bearing θi and the link, Dgps is the length of the vertical line dropped from the GPS measurement position to the link, and k1 to k3 are It is a coefficient.

(d) When the projection method correlation value Z is obtained, a link having the smallest value Z is set as a matching candidate (optimum road). Here, the link LKa1 is obtained.
(e) The travel locus SHi connecting the point Pi-1 and the point Pi 'is translated in the direction of the perpendicular line RLia until the point Pi-1 is on the link LKa1 (or on the extension line of the link LKa1). -1 and Pi 'moving points PTi-1 and PTi' are obtained.
(f) Finally, a rotational point is obtained by rotating and moving around the point PTi-1 until PTi 'is on the link LKa1 (or on the extension line of the link LKa1), and set as the actual vehicle position Pi (Xi, Yi). . Note that the vehicle orientation at the actual vehicle position Pi (Xi, Yi) remains θi.

The map matching process described above is a case where the measurement position P _S1 by the self-contained navigation is not separated from the GPS measurement position P _G1 by a set distance, for example, 50 m or more as shown in FIG. That is, when the measurement position P _S1 by the self-contained navigation exists within the GPS error circle, the map matching process is performed to correct the measurement position P _S1 by the self-contained navigation to the map matching position P _M1 on the road link RD. Note that P _M0 is the previous map matching position.
On the other hand, when the measurement position P _S1 by autonomous navigation, as shown in FIG. 10 (B) is apart a set distance, for example, 50m or more from the GPS measurement position P _G1, that is, the measurement position P _S1 by autonomous navigation GPS error If the vehicle exists outside the circle, the vehicle position is corrected to the GPS measurement position P _G1 , and then the map matching process is performed to correct the map matching position P _M1 on the road link RD. Note that P _M0 is the previous map matching position.
Since the projection map matching process can only correct in the horizontal direction, there is a problem in that the front-to-back displacement cannot be absorbed when the distance error accumulates. That is, when the measurement position P _S1 by the self-contained navigation is within a set distance, for example, 50 m from the GPS measurement position P _G1 (FIG. 10A), there is a problem that correction is not possible even if the longitudinal deviation D increases. Further, when the vehicle position is outside the GPS error circle, in order to map matching after correcting the vehicle position to the GPS position P _G1 (FIG. 10 (B)), a sudden jump in position occurs, the appearance It was not good, and there was a problem that gave a bad impression to users.
The above is the projection map matching process based on the self-contained navigation measurement position, but there is also the projection map matching process based on the GPS measurement position.
This map matching process based on the self-contained navigation measurement position is a map matching of the GPS measurement position on the road link. Similar to the map matching process based on the self-contained navigation measurement position, every time the vehicle travels a predetermined distance L0. As long as it is less than L0, the vehicle position is measured and displayed by self-contained navigation.

FIG. 11 is a diagram for explaining the problem of the projection map matching process based on the GPS measurement position. In the projection map matching process based on the GPS measurement position, if the GPS position cannot be used due to shielding such as tunnels, buildings, and roadside trees (non-positioning section), the map matching process becomes impossible during that time. In the self-contained navigation, distance errors accumulate and become large. In this state, when the GPS positioning is enabled and the projection map matching process based on the GPS measurement position P _G1 is performed, the vehicle position is changed from the autonomous navigation measurement position P _S1 to the map matching position as shown in FIG. P _M1 suddenly jumps in position, looks bad and gives a bad impression to the user. In other words, if the non-positioning section becomes longer, the distance between the measurement position P _S1 by the self-contained navigation and the GPS measurement position P _{G1 at the} time when GPS positioning becomes possible may increase, and the measurement position P _S1 by the self-contained navigation and the map The distance D between the matching positions P _M1 increases and a sudden position jump occurs. This is the same as in the case of FIG. Note that P _M0 is the previous map matching position.
Further, in the projection map matching process based on the GPS measurement position, an unspecified error is included in the GPS measurement position. Therefore, as shown in FIG. There are times when positioning. In the figure, P _G0 is the previous GPS measurement value, P _M0 is the previous map matching position, P _G1 is the current GPS measurement value, and P _M1 is the current map matching position.
Further, in the projection map matching process based on the GPS measurement position, as shown in FIG. 11C, mismatch may occur in road links RD1 and RD2 that branch at a minute angle due to a lateral error. In the figure, P _G0 is the previous GPS measurement, P _M0 is the previous map matching position, P _G1 is the previous GPS measurement, P _M1 is the previous map matching position, P _G2 is the current GPS measurement, and P _M2 Is the current map matching position, and P _M2 ′ is the position on the road where the vehicle is actually traveling.
From the above, it is necessary to reduce the distance shift in the front-rear direction (front-rear shift) and to prevent a sudden jump in position due to the map matching process.
There is a navigation device that determines the weight based on the reliability of the GPS measurement position, calculates the weighted average of the GPS measurement position and the autonomous navigation measurement position as the current position, and performs map matching processing using the current position ( Patent Document 2). However, this prior art does not reduce the distance deviation (front-rear deviation) in the vehicle front-rear direction, and does not prevent a sudden jump in position due to the map matching process.
JP 2004-226341 A JP 2005-326196 A

Accordingly, an object of the present invention is to reduce a distance error (front-rear deviation) in the vehicle front-rear direction, and to prevent a sudden jump in position due to map matching processing.
Another object of the present invention is to correct a distance error in the vehicle front-rear direction without the user's knowledge and prevent a sudden jump in position due to the map matching process.
Another object of the present invention is to reduce the influence of GPS error and prevent mismatching at a small angle branch point or the like.
Another object of the present invention is to enable a map matching process in consideration of a delay in calculation time of a GPS measurement position.

A first aspect of the present invention is a vehicle position correction method for correcting a vehicle position using a vehicle measurement position measured by a self-contained navigation and a vehicle measurement position measured by a GPS measurement method. A perpendicular line from the GPS measurement position to a straight line extending from the position in the vehicle azimuth direction, and calculating a distance connecting the self-contained navigation measurement position and the foot of the vertical line, the self-contained navigation measurement position in the vehicle azimuth direction The method includes a step of setting a position obtained by shifting a predetermined percentage of the distance as a vehicle position, and correcting the vehicle position by map matching on a road link.
In the vehicle position correction method according to the first aspect, a distance vector traveled by the vehicle during the time dT required for GPS position calculation is further obtained, and the distance vector is added to the GPS measurement position to obtain a true GPS measurement position. A step, and calculating the distance using the self-contained navigation position after the dT and the true GPS measurement position. The vehicle position correction method according to the first aspect further includes a step of monitoring the reliability of the GPS measurement position, and performs the vehicle position correction when the reliability of the GPS measurement position is high.
A second aspect of the present invention is a vehicle position correction method for correcting a vehicle position using a vehicle measurement position measured by a self-contained navigation and a vehicle measurement position measured by a GPS measurement method. Map-matching a position to a position on a road link; dropping a perpendicular from the GPS measurement position to the road link; calculating a distance connecting the autonomous navigation position after the map matching and the leg of the perpendicular; the autonomous navigation There is a step of setting the position obtained by shifting the position in the road link direction by a predetermined percentage of the distance as the vehicle position.
The vehicle position correction method of the second aspect further obtains a distance vector that the vehicle moves during the time dT required for GPS position calculation, and adds the distance vector to the GPS measurement position to obtain a true GPS measurement position. A step, and calculating the distance using the self-contained navigation position after the dT and the true GPS measurement position. The vehicle position correction method of the second aspect further includes a step of monitoring the reliability of the GPS measurement position, and performs the vehicle position correction when the reliability of the GPS measurement position is high.
A third aspect of the present invention is a vehicle position correction device that corrects a vehicle position using a vehicle measurement position measured by a self-contained navigation and a vehicle measurement position measured by a GPS measurement method. A self-contained navigation position measuring unit for measuring the vehicle position, a GPS position measuring unit for measuring the vehicle position by a GPS measurement method, a perpendicular line extending from the measurement position by the self-contained navigation in a vehicle azimuth direction from the GPS measurement position, and the self-contained navigation The distance between the measurement position and the perpendicular foot is calculated, the position obtained by shifting the self-contained navigation measurement position by a predetermined percentage of the distance in the vehicle azimuth direction is defined as the vehicle position, and the vehicle position is the road link. A vehicle position correction unit for correcting by map matching is provided. The vehicle position correction unit obtains a distance vector traveled by the vehicle during a time dT required for GPS position calculation, adds the distance vector to the GPS measurement position to obtain a true GPS measurement position, and is self-supporting after the dT The distance is calculated using the navigation position and the true GPS measurement position.
The vehicle position correction device according to the third aspect further includes a reliability monitoring unit that monitors the reliability of the GPS measurement position, and the vehicle position correction unit performs the vehicle position correction when the reliability of the GPS measurement position is high. Do.
A fourth aspect of the present invention is a vehicle position correction device that corrects a vehicle position using a vehicle measurement position measured by a self-contained navigation and a vehicle measurement position measured by a GPS measurement method. A self-contained navigation position measurement unit that measures vehicle position, a GPS position measurement unit that measures vehicle position by GPS measurement method, map-matching the measurement position by the self-contained navigation to a position on a road link, and a perpendicular line from the GPS measurement position to the road link And calculating a distance connecting the autonomous navigation position after the map matching and the foot of the perpendicular, and shifting the autonomous navigation position by a predetermined percentage of the distance in the road link direction to determine the vehicle position. A vehicle position correction unit is provided. The vehicle position correction unit obtains a distance vector traveled by the vehicle during a time dT required for GPS position calculation, adds the distance vector to the GPS measurement position to obtain a true GPS measurement position, and is self-supporting after the dT The distance is calculated using the navigation position and the true GPS measurement position.
The vehicle position correction apparatus according to the fourth aspect further includes a reliability monitoring unit that monitors the reliability of the GPS measurement position, and the vehicle position correction unit performs the vehicle position correction when the reliability of the GPS measurement position is high. Do.

According to the present invention, the vehicle position is corrected so that the self-contained navigation measurement position is gradually shifted in the GPS measurement position direction along the vehicle azimuth direction or the road link. The map matching process can prevent a sudden jump in position.
Further, according to the present invention, the distance error in the vehicle front-rear direction can be corrected without the user's knowledge, and a bad impression can be prevented from being given to the user.
In addition, according to the present invention, since the map matching process considering the calculation time delay of the GPS measurement position is performed, the vehicle position accuracy can be improved.
Further, according to the present invention, the vehicle position is corrected so as to shift the self-contained navigation measurement position little by little in the direction of the GPS measurement position, and the vehicle position is corrected only when the reliability of the GPS measurement value is high. Even if the GPS error becomes large, the influence of the GPS error can be reduced and mismatching at a small angle branch point can be prevented.

(A) Principle of the Present Invention FIG. 1 is an explanatory view of the principle of the present invention, FIG. 1 (A) is an explanatory view for correcting the vehicle position in the direction of the vehicle direction, and FIG. It is explanatory drawing which performs the front-back correction | amendment of the own vehicle position in a road link direction.
In FIG. 1 (A), the vehicle measurement position by self-contained navigation is P _S1 , the vehicle azimuth at the measurement position is θ, and a perpendicular line from the measurement position P _G1 by GPS extends to the straight line LK extended in the azimuth direction (direction vector direction) down, to the foot of the perpendicular line to the P _GM.
Every predetermined distance (e.g. 20 m) travel, or a predetermined time (e.g., 1 second) for each travel, the foot measurement position P _S1 and the perpendicular by autonomous navigation to determine the P _GM, fixed distance D and the distance D between them The distance d (= D / 4) of the ratio (for example, 25%) is calculated. Next, the measurement position P _S1 by the self-contained navigation is shifted in the direction vector direction by the distance d, and the position P _C1 ′ after the shift is set as the vehicle position. Thereafter, the vehicle position P _C1 ′ is corrected on the road link by map matching processing, and a vehicle position mark is displayed at the vehicle position.

In FIG. 1B, when the measurement position P _S1 by the self-contained navigation is corrected to a position on the road link by map matching, the map matching position is set to P _M1 ′. Also road link RD
A perpendicular line is dropped from the GPS measurement position P _G1 to be foot of the perpendicular line of the P _GM.
A predetermined distance (e.g. 20 m) for each run or for a predetermined time (e.g., 1 second) for each run to obtain the P _GM foot of a perpendicular line between the map matching position P _M1 ', a percentage of the distance D and the distance D between them, A distance d (= D / 4) of (for example, 25%) is calculated. Next, the map matching position P _M1 ′ is shifted along the road link in the direction of the perpendicular foot P _{GM by} the distance d, the position after the shift is set as the vehicle position P _C1 , and a vehicle position mark is displayed at the position.
According to the present invention, the distance error is corrected by correcting the position at a certain rate (for example, 25%) in the GPS positioning position direction every certain distance (for example, 20 m) or every certain time (for example, 1 second). Accumulation can be eliminated.
In addition, since the GPS measurement position is gradually approached, the vehicle position can be corrected in the vicinity of the GPS position without the user's knowledge, and a sudden position jump does not occur in the map matching process.
Also, even if the GPS positioning position error temporarily increases, only a fixed percentage of distance error is corrected, and the vehicle position is corrected only when the GPS measurement value is highly reliable. Can also reduce the effects of GPS errors and prevent mismatching at minute corners.

The following table shows the merits and demerits of the conventional self-contained navigation position reference (FIG. 10), the GPS position reference (FIG. 11), and the position correction method of the present invention.

(B) First Embodiment FIG. 2 is an explanatory diagram of the first embodiment. The measurement position P _S1 ′ (FIG. 2 (A)) by self-contained navigation and the measurement position P _G1 ′ by GPS are acquired every time a certain distance (for example, 20 m) or every certain time (for example, one second).
The measurement position P _S1 ′ by self-contained navigation can be calculated without time delay, but the measurement position P _G1 ′ by GPS requires dT time for calculation. During this delay time dT, the measurement position by autonomous navigation is to P _S1 from P _S1 '(dX, dY) shifts. Therefore, the position P _S1 after the delay time dT is set as the true measurement position by the self-contained navigation, and the position obtained by adding the distance vector (dX, dY) to the GPS measurement position P _G1 ′ is the measurement position P _G1 by the true GPS. To do.
Next, as shown in FIG. 2 (B), the vehicle measurement position P _S1 by self-contained navigation and the vehicle azimuth at the measurement position is θ, and a perpendicular is drawn from the measurement position P _G1 by GPS to the straight line LK extending in the azimuth direction. , to the foot of the perpendicular line to the P _GM. Thereafter, to calculate a percentage of the distance D and the distance D between the feet of the measuring position P _S1 and the perpendicular by autonomous navigation P _GM (e.g. 25%) the distance d (= D / 4) of the.
When the distance d is obtained, the measurement position P _S1 by the self-contained navigation is shifted by the distance d in the direction vector direction, and the position P _C1 ′ after the shift is set as the vehicle position by the self-contained navigation. Thereafter, as shown in FIG. 2C, the vehicle position P _C1 ′ is corrected on the road link RD by map matching processing similar to that of the prior art. The corrected position P _C1 becomes the vehicle position after correction by final map matching, and a vehicle position mark is displayed at the vehicle position.

FIG. 3 is a configuration diagram of a navigation device including the vehicle position correction unit of the present invention.
Map data is recorded on a map recording medium (CD-ROM, DVD, HDD, etc.) 1 and can be read as necessary. A GPS receiver 2 receives and outputs GPS radio waves sent from GPS satellites, and a self-contained navigation sensor 3 includes an angle sensor (gyro) 3a that detects a vehicle rotation angle and a distance sensor that generates a pulse at every predetermined travel distance. 3b. The navigation control unit 4 performs vehicle position detection / correction control, vehicle periphery map image generation control, route search / guidance control, intersection guidance control, and the like. The monitor 5 displays a vehicle periphery map, a guidance route, a vehicle position mark, other guidance information and a menu in accordance with instructions from the navigation device 4.

In the navigation control unit 4, the map reading unit 11 reads map data around the vehicle position from the map storage medium 1 and stores it in the map buffer 12. The map buffer 12 holds a map leaf and a peripheral map leaf according to the vehicle position, and can scroll the map according to the travel. The map drawing unit 13 generates a map image around the vehicle using the map data read to the map buffer 12 and stores it in the VRAM 14, and the combining unit 15 reads the map image read from the VRAM, the vehicle position mark, and the guidance. A route image or the like is synthesized and displayed on the monitor 5.
The GPS position calculation unit 16 calculates and outputs the own vehicle position (GPS measurement position) based on the GPS received data, and the self-contained navigation position calculation unit 17 calculates the direction and movement distance input from the self-contained navigation sensor 3 (1 ) ~ (3) to calculate the vehicle position (autonomous navigation measurement position) and output. The GPS reliability determination unit 18 determines the reliability of the GPS measurement position.

FIG. 4 is an explanatory diagram of the GPS reliability determination control. The GPS reliability determination unit 18 calculates the distance Ltrace of the self-contained navigation measurement position trajectory in a certain section and the distance Lgps of the GPS measurement position trajectory in the same section, and based on the magnitude of the absolute value | Ltrace−Lgps | To determine the reliability. That is, the GPS reliability determination unit 18 determines that the GPS reliability is high if the difference is smaller than the threshold. In FIG. 4, a circle is a self-contained navigation measurement position, a cross is a GPS measurement position, and a CM is a vehicle position mark. FIG. 4A is an example in which | Ltrace-Lgps | is smaller than the threshold and the reliability of GPS data is high, and FIG. 4B is an example in which | Ltrace-Lgps | is greater than the threshold and the reliability of GPS data is low. is there.
The vehicle position correction unit 19 performs a vehicle position correction process, which will be described later, using the GPS measurement position and the self-contained navigation measurement position for each predetermined movement distance or for each predetermined time, and corrects the vehicle position on the road link. The vehicle position mark generation unit 20 generates a vehicle position mark at the vehicle position on the map and inputs it to the synthesis unit 15. In addition to the above, the navigation control unit 4 includes a portion for performing guidance route generation and route guidance control, a portion for performing intersection enlarged display / guidance, and the like, which are not related to the present invention, and thus will be omitted.

FIG. 5 is a processing flow of position correction control of the vehicle position correction unit 19. The GPS position calculation unit 16 and the self-contained navigation position calculation unit 17 calculate the GPS position P _G1 ′ (see FIG. 2A) and the self-contained navigation position P _S1 ′ at predetermined time intervals, respectively, and the vehicle position correction unit 19. And input to the GPS reliability determination unit 18.
The vehicle position correction unit 19 monitors whether the vehicle has traveled a certain distance (for example, 20 m) (step 101), and checks whether the GPS reliability is high if the vehicle travels a certain distance (step 102). If the GPS reliability is low, the vehicle position correction process is terminated and the next fixed distance traveling is monitored. If the GPS reliability is high, the vehicle position correcting unit 19 obtains the autonomous navigation position P _S1 (see FIG. 2) after the time dT required for calculating the GPS measurement position, and calculates the autonomous navigation movement distance (dX, dY) at the time dT. determined (step 103), the distance vector GPS position P _G1 '(dX, dY) were added to calculate the true GPS measurement position P _G1 (step 104).
Next, as shown in FIG. 2B, the vehicle position correcting unit 19 sets the vehicle measurement position P _S1 by self-contained navigation, the vehicle azimuth at the measurement position as θ, and the measurement position by GPS on the straight line LK extended in the azimuth direction. P _G1 a perpendicular line is dropped from and foot of the perpendicular line of the P _GM (step 105). Thereafter, the vehicle position correcting unit 19 calculates a certain percentage of the distance D and the distance D between the feet of the measuring position P _S1 and the perpendicular by autonomous navigation and P _GM (e.g. 25%) the distance d (= D / 4) of the Then, the measurement position P _S1 by the self-contained navigation is shifted by the distance d in the direction vector direction, and the shifted position P _C1 ′ is set as the vehicle position by the self-contained navigation (step 107). Thereafter, as shown in FIG. 2C, the vehicle position correcting unit 19 corrects the vehicle position P _C1 ′ on the road link RD by the same map matching process as in the prior art (step 108). The corrected position P _C1 becomes the vehicle position by the final map matching of the first embodiment, and a vehicle position mark is displayed at the position.

(C) Second Embodiment FIG. 6 is an explanatory diagram of the second embodiment. The measurement position P _S1 (FIG. 6 (A)) and the measurement position P _G1 ′ by GPS are acquired every time the vehicle travels a fixed distance (for example, 20 m) or every fixed time (for example, 1 second). Next, the measurement position P _S1 by the self-contained navigation is corrected to a position on the road link RD by map matching, and the position is set as a map matching position P _M1 ′. 'Since takes dT time the calculation of, during this time delay dT, the vehicle position is P _M1' GPS position P _G1 from the P _M1 (dX, dY) shifts. Therefore, the position P _M1 after dT is set as the true map matching position, and the position obtained by adding the distance vector (dX, dY) to the GPS measurement position P _G1 ′ is set as the true GPS measurement position P _G1 .
Thereafter, a perpendicular line is dropped from the GPS measurement position P _G1 to road link RD as shown in FIG. 6 (B), to the foot of the perpendicular line of the P _GM. Then, to calculate the distance a percentage of the distance D and the distance D between the map matching position P _M1 and perpendicular foot P _GM (e.g. 25%) d (= D / 4). If the distance d is obtained, to shift the map matching position P _M1 by the distance d in the road link direction, the position P _C1 after the shift and the vehicle position P _C1, and displays a vehicle position mark on the position.

FIG. 7 is a processing flow of position correction control of the second embodiment. The navigation device of the second embodiment has the same configuration as the navigation device of the first embodiment of FIG.
The GPS position calculation unit 16 and the self-contained navigation position calculation unit 17 calculate the GPS position P _G1 ′ (see FIG. 6A) and the self-contained navigation position P _S1 , respectively, at predetermined time intervals. Input to the degree determination unit 18.
The vehicle position correction unit 19 monitors whether the vehicle has traveled a certain distance (for example, 20 m) (step 201), and checks whether the GPS reliability is high if the vehicle travels a certain distance (step 202). If the GPS reliability is low, the vehicle position correction process is terminated and the next fixed distance traveling is monitored. If the GPS reliability is high, the vehicle position correcting unit 19 corrects the self-contained navigation position P _S1 to a position on the road link RD by map matching, and sets the position as the map matching position P _M1 ′ (step 203).
Next, the vehicle position correcting unit 19 obtains a self-contained navigation position P _M1 (see FIG. 6 (A)) after the time dT required for calculating the GPS measurement position, and obtains the movement distance (dX, dY) at the time dT (step 204). Then, the true GPS measurement position P _G1 is calculated by adding the distance vector (dX, dY) to the GPS position P _G1 ′ (step 205).
Then, the vehicle position correcting unit 19 as shown in FIG. 6 (B), the road link RD a perpendicular line is drawn from the GPS fixes P _G1, to the foot of the perpendicular line of the P _GM (step 206). Thereafter, the vehicle position correcting unit 19 calculates the distance D between the self-contained navigation position P _M1 on the road and the foot P _{GM of the} normal line and a distance d (= D / 4) at a constant rate (for example, 25%) of the distance D. (step 207), the autonomous navigation position P _M1 is shifted by the distance d in the direction of the foot P _GM perpendiculars along the road link, the position P _C1 after the shift and the vehicle position (step 208). Thereafter, the vehicle position P _C1 becomes the vehicle position by final map matching according to the second embodiment, and a vehicle position mark is displayed at the position.

  As described above, according to the first and second embodiments, the distance error (front-rear deviation) in the front-rear direction can be reduced. In addition, the distance error in the front-rear direction can be corrected little by little before the user notices, and a sudden position jump can be prevented by the map matching process. In addition, the influence of GPS errors can be reduced, and mismatching at minute corners can be prevented. In addition, it is possible to perform a map matching process that takes into account the delay in calculating the GPS measurement position.

It is a principle explanatory view of the present invention. It is explanatory drawing of 1st Example. It is a block diagram of the navigation apparatus containing the vehicle position correction | amendment part of this invention. It is explanatory drawing of GPS reliability determination control. It is a processing flow of position correction control of the first embodiment. It is explanatory drawing of 2nd Example. It is a processing flow of position correction control of the second embodiment. It is explanatory drawing of the vehicle position estimation method by the conventional self-contained navigation. It is explanatory drawing of the map matching by a projection method. It is explanatory drawing of the map matching process on the basis of self-contained navigation. It is explanatory drawing of the map matching process on the basis of GPS.

Explanation of symbols

P _S1 ′ Measurement position by self-contained navigation
P _G1 ′ GPS measurement position
P _S1 Self-contained navigation position after GPS delay
P _G1 True GPS position after GPS estimated time delay
P _GM perpendicular foot
P _C1 ′ Vehicle position
Vehicle position by P _C1 map matching
LK A straight line indicating the azimuth direction
RD road link

Claims (10)

In the vehicle position correction method for correcting the vehicle position using the vehicle measurement position measured by the self-contained navigation and the vehicle measurement position measured by the GPS measurement method,
A step of lowering a perpendicular from the GPS measurement position to a straight line extending in the vehicle azimuth direction from the measurement position by the self-contained navigation, and calculating a distance connecting the self-contained navigation measurement position and the foot of the perpendicular;
Setting the position obtained by shifting the self-contained navigation measurement position by a predetermined percentage of the distance in the vehicle azimuth direction as a vehicle position;
Correcting the vehicle position by map matching on a road link;
A vehicle position correction method comprising: Find the distance vector that the vehicle moves during the time dT required for GPS position calculation, add the distance vector to the GPS measurement position to be a true GPS measurement position,
Performing the process of the step using the self-contained navigation position after the dT and the true GPS measurement position,
The vehicle position correction method according to claim 1. In the vehicle position correction method for correcting the vehicle position using the vehicle measurement position measured by the self-contained navigation and the vehicle measurement position measured by the GPS measurement method,
Map-matching the measurement position by the self-contained navigation to a position on a road link;
Dropping a perpendicular from the GPS measurement position to the road link, and calculating a distance connecting the self-contained navigation position after the map matching and the foot of the perpendicular;
A step of setting the position obtained by shifting the self-contained navigation position by a predetermined percentage of the distance in the road link direction as a vehicle position;
A vehicle position correction method comprising: Find the distance vector that the vehicle moves during the time dT required for GPS position calculation, add the distance vector to the GPS measurement position to be a true GPS measurement position,
The processing is performed using the self-contained navigation position after the dT and the true GPS measurement position.
The vehicle position correction method according to claim 3.   5. The vehicle position correction method according to claim 1, wherein the reliability of the GPS measurement position is monitored, and the vehicle position correction is performed when the reliability of the GPS measurement position is high. In a vehicle position correction apparatus that corrects a vehicle position using a vehicle measurement position measured by self-contained navigation and a vehicle measurement position measured by a GPS measurement method,
A self-contained navigation position measurement unit that measures the vehicle position by self-contained navigation,
GPS position measurement unit that measures vehicle position by GPS measurement method,
A vertical line is drawn from the GPS measurement position to a straight line extending in the vehicle azimuth direction from the measurement position by the self-contained navigation, a distance connecting the self-contained navigation measurement position and the foot of the vertical line is calculated, and the self-contained navigation measurement position is defined as the vehicle. A vehicle position correcting unit that corrects the vehicle position by map matching on a road link, with a position obtained by shifting the azimuth direction by a predetermined percentage of the distance as a vehicle position,
A vehicle position correction apparatus comprising: The vehicle position correction unit obtains a distance vector traveled by the vehicle during a time dT required for GPS position calculation, adds the distance vector to the GPS measurement position to obtain a true GPS measurement position, and is self-supporting after the dT Calculating the distance using the navigation position and the true GPS measurement position;
The vehicle position correction apparatus according to claim 6. In a vehicle position correction apparatus that corrects a vehicle position using a vehicle measurement position measured by self-contained navigation and a vehicle measurement position measured by a GPS measurement method,
A self-contained navigation position measurement unit that measures the vehicle position by self-contained navigation,
GPS position measurement unit that measures vehicle position by GPS measurement method,
Map-matching the measurement position by the self-contained navigation to a position on a road link, dropping a perpendicular line from the GPS measurement position to the road link, calculating a distance connecting the self-contained navigation position after the map matching and the leg of the perpendicular line, A vehicle position correction unit having a position obtained by shifting the self-contained navigation position by a predetermined percentage of the distance in the road link direction;
A vehicle position correction apparatus comprising: The vehicle position correction unit obtains a distance vector traveled by the vehicle during a time dT required for GPS position calculation, adds the distance vector to the GPS measurement position to obtain a true GPS measurement position, and is self-supporting after the dT Calculating the distance using the navigation position and the true GPS measurement position;
The vehicle position correction apparatus according to claim 8.   10. The reliability monitoring unit that monitors the reliability of the GPS measurement position, and the vehicle position correction unit performs the vehicle position correction when the reliability of the GPS measurement position is high. Vehicle position correction apparatus.

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