JP2807140B2 - Vehicle position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle position detecting device, such as a so-called navigation system, for detecting where a vehicle is currently running.

[0002]

2. Description of the Related Art Conventionally, a vehicle position detecting device mounted on a vehicle and displaying an image of the current position of the vehicle in real time has been commercialized. The current position of the vehicle is calculated according to dead reckoning. Dead reckoning in vehicles is
The travel distance and the azimuth from the determined position are calculated by synthesizing a travel vector detected based on a signal from a sensor mounted on the vehicle.

When the current position is detected only by dead reckoning navigation, detection errors of the sensors and the like are accumulated. Map matching is performed in order to avoid accumulation of errors and improve the detection accuracy of the current position. Map matching uses the fact that a vehicle travels on a road in principle. The traveling locus obtained by dead reckoning is compared with the shape of the road, and the running road is specified to correct the error. For example, FIG.
As shown in (a), the vehicle travels on the road La, and
And the current position is Pa0. Starting point P
From a, proceed to Pa5, Pa4, and at Pa3, the road La
Corrected to the upper position. The process further proceeds to Pa2 and Pa1, and is corrected again to the position on the road La at the current position Pa0.

[0004]

In a conventional position detecting device, local map matching is performed to correct the current position. Therefore, although map matching is possible in a certain range as shown in FIG. 7A, map matching may not always be possible as shown in FIG. 7B. That is, even if the first position Pb is on the road Lb, Pb5, Pb
4, from Pb3, Pb2, Pb1 to Pb0 at the current position, it cannot be corrected on the road Lb, and passes along a route different from the apparent upper road Lb. Thus, once a mismatch occurs, it is difficult to return, and in the worst case, the result will diverge.

An object of the present invention is to provide a vehicle position detecting device capable of improving detection accuracy when an error becomes large only by local map matching.

[0006]

According to the present invention, there is provided a vehicle position detecting device for detecting a current position of a running vehicle, wherein the current position of the vehicle is determined based on a signal representing a running vector following the running of the vehicle. A first position detecting means for calculating and performing local map matching with road data stored in advance to correct the calculated current position on the road; and a first position detecting means for correcting the current position corrected by the first position detecting means. When the reliability of the current position by the reliability evaluation means for evaluating the reliability is lower than a predetermined reference and the number of correction candidate positions is equal to or more than a reference value, the global position data is And a second position detecting means for detecting the current position based on the current position.

[0007] The second position detecting means of the present invention, in response to a vehicle signal, synthesizes a travel vector to create pattern data representing a travel locus, and performs pattern matching with prestored road data. To correct the current position.

[0008] Further, the second position detecting means of the present invention is characterized in that G
The current position is corrected by receiving a radio wave from a PS satellite.

[0009]

According to the present invention, the first position detecting means calculates the current position of the vehicle on the basis of the running vector following the running of the vehicle, and performs local map matching with road data stored in advance. To correct the current position on the road. When the reliability of the current position corrected by the first position detecting means is lower than a predetermined reference value and the number of correction candidate positions is equal to or more than the reference value, the second position detection is performed. The means corrects the current position based on the global position data. When the reliability is high by local map matching, the first position detecting means detects the current position, and when the reliability is low, the second position detecting means globally corrects the current position. Thereby, the detection accuracy of the current position can be improved. As long as the reliability of the current position detected by the first position detecting means is high, no correction is performed by the second position detecting means, so that quick processing can be performed.

Further, according to the present invention, the second position detecting means synthesizes the traveling vectors to create pattern data representing the traveling locus, and performs pattern matching with road data stored in advance. Since the patterns formed by roads are finite, it is easy to find global similarity by performing overall pattern matching.

According to the present invention, the second position detecting means receives the radio wave from the GPS satellite and corrects the current position, so that the second position detecting means can detect the current position as an absolute value independently of the running state.

[0012]

FIG. 1 shows a schematic configuration of a vehicle position detecting device according to an embodiment of the present invention. The wheel speed sensor 1 derives a signal corresponding to the traveling speed of the vehicle. Orientation sensor 2
Is realized by a geomagnetic sensor, a vibration gyro sensor, or the like, and derives a signal indicating the traveling direction of the vehicle. The vehicle signal processing device 3 derives a vehicle signal representing a traveling vector of the vehicle in response to the traveling speed and traveling direction of the vehicle. The micro map matching position detecting device 4 as the first position detecting means calculates the current position of the vehicle by dead reckoning navigation based on the vehicle signal from the vehicle signal processing device 3. The calculated current position is displayed as a current position 6 on a display 5 such as a cathode ray tube (abbreviated as “CRT”) or a liquid crystal display (abbreviated as “LCD”). The display 7 also displays the road 7 and the like at the same time. This road data is stored in the CD-ROM 8 or the like in advance. The micro map matching position detecting device 4 performs a map matching between the road data stored in the CD-ROM and the current position calculated by dead reckoning, and corrects the current position if the matching is possible. However, matching is not always possible uniquely.

The reliability of the current position detected by the micro map matching position detecting device 4 is evaluated by the reliability evaluating device 9. When the reliability is low, the macro map matching position detecting device 11 that performs pattern matching with the road data is activated based on the traveling locus pattern data created by the traveling locus recording device 10. In the macro map matching position detecting device 11 which is the second position detecting means, the pattern data of the traveling locus is
The current position is corrected by globally comparing road data stored in the CD-ROM and performing pattern matching similar to that in the field of character recognition. The vehicle signal processing device 3, the micro map matching position detecting device 4, the reliability evaluating device 9, the traveling locus recording device 10, and the macro map matching position detecting device 11 as described above are a multi-processing device 12 including a CPU and a memory. It is realized by a task program operation. Of course, other configurations such as parallel operation of a plurality of computer devices may be used.

FIG. 2 shows the operation of the configuration shown in FIG. The operation starts from step a1, and the current position is detected by dead reckoning in step a2. At step a3, it is determined whether or not the detected current position can be corrected by micro map matching. When the correction is not possible, the process proceeds to step a4, and it is determined whether or not the distance for which the dead reckoning navigation is continued is equal to or more than a reference value. If not, the process returns to step a2.

If it is determined in step a3 that correction by micro map matching is possible, step a5
Performs micro map matching correction. In step a6, the degree of micro map matching is evaluated, and the evaluation value is compared with a reference value. When it is determined that the evaluation value is not less than the reference value, the process proceeds to step a7. In step a7, the number of candidates to be corrected is obtained. When it is determined that the number of candidates is not more than the reference value, the process returns to step a2.

When it is determined in step a4 that the dead reckoning distance is equal to or greater than the reference value, when it is determined in step a6 that the evaluation value is equal to or less than the reference value, and in step a7, the number of candidates is equal to or greater than the reference value. When the determination is made, the process proceeds to step a8, where global correction is performed by the macro map matching position detecting device 11, and the process returns to step a2.

FIG. 3 shows the principle of pattern matching in the macro map matching position detecting device 11 shown in FIG. As shown in FIG. 3A, the traveling locus recording device 1
From 0, the running locus pattern is set to the history data H0, H
Are derived as 1,. Each piece of history data includes data representing a distance and an azimuth by summing up a running vector every moment within a range of the same azimuth. FIG. 3 (b) is the same as FIG.
The road data to be matched with the trajectory pattern is shown.
The road data also includes nodes N0,
N1, N2, N3 and link L corresponding to the road between them
Abstract like 1, L2, L3. Nodes N0 to N3
Is coordinate data representing the position. Links L1 to L
3 has data representing its length and orientation.

The global pattern matching is started by going back from the latest history data H0. H0
Can be matched with L1 and L3, and there are two candidates. However, when the history data H1 is further added, the links that can be matched are L1 and L1.
2 only. Therefore, the current position is node N
It is determined to be zero. The above is the operation principle of the macro map matching position detecting device 11.

FIG. 4 shows that one history data H10 is 2
Shows a state that includes two links and is matched. That is, the history data H10 shown in FIG. 4A has a distance d10 and an azimuth θ10. On the other hand, FIG.
Can be matched with the links L11 and L12 shown in FIG. The link L11 has a distance d11 and an azimuth θ11. The link L12 has a distance d12 and an azimuth θ12. The absolute value of the difference between θ10 and θ11 and θ12 is smaller than a predetermined reference value, and distance d10 is equal to distances d11 and d11.
12 is substantially equal to the sum of the history data H1
0 is determined to be the sum of the links L11 and L12.

FIG. 5 shows the history data H2 shown in FIG.
0 indicates a state in which a combination of the two pieces of history data shown in FIG. That is, although there is one link from the node N20 to the node N21 via the link L21, the node N21 branches off from the node N21, and it is not possible to determine which route it is. Node N21
From the path leading to the node N22 via the link L22 and the path leading to the node N23 via the link L23, there is little change in the mutual azimuth and little change in the link distance. In such a case, it is determined which route the route is by global pattern matching including more history data.

FIG. 6 shows a schematic configuration of another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 1 and corresponding parts are denoted by the same reference numerals. It should be noted that the GPS receiver 21 receives satellite radio waves of the GPS system from the antenna 20 and thereby corrects the current position. The operation of the reliability evaluation device 9 is the same as that of the embodiment shown in FIG.

In the above embodiment, the reliability evaluation device 9 determines the reliability by determining the distance traveled by dead reckoning navigation, the evaluation value of the current micromap-matched road, and the number of micromap matching candidates. Although the determination is made in combination, it is needless to say that the determination may be made by using only one or two in combination. Further, when the driver determines that the current running state and the display state do not match while watching the display 5, it is needless to say that the driver may be activated by operating a switch.

Although the macro map matching position detecting device 11 and the GPS receiving device 21 are shown as the second position detecting means, a position beacon from a sign post installed on the road may be used. Of course.

[0024]

As described above, according to the present invention, the first position detecting means detects the current position by performing dead reckoning navigation and local map matching. When the reliability of the current position is low and the number of correction candidates is large, correction is performed by global position detection by the second position detection means, so that the accuracy of the detected current position is improved. Since the second position detecting means corrects the current position only when the reliability of the current position detected by the first position detecting means is low and there are many correction candidates, normally only the first position detecting means operates. I just need. Therefore, the current position can be quickly detected. Since the second position detecting means only needs to perform the correction when the reliability of the current position detected by the first position detecting means is low and there are many correction candidates, it is possible to sufficiently increase the processing time and improve the reliability of the detection. .

Further, according to the present invention, the second position detecting means corrects the current position by performing pattern matching between the pattern data representing the traveling locus and the road data stored in advance, so that the vehicle travels quickly. Possible roads and intersections can be specified, and the current position can be easily corrected.

Further, according to the present invention, the second position detecting means receives the radio wave from the GPS satellite and corrects the current position, so that the second position detecting means can perform the correct correction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the configuration of FIG.

FIG. 3 is a diagram showing the principle of pattern matching in the embodiment of FIG.

FIG. 4 is a diagram showing the principle of pattern matching in the embodiment of FIG.

FIG. 5 is a diagram showing the principle of pattern matching in the embodiment of FIG.

FIG. 6 is a block diagram showing a schematic electrical configuration of another embodiment of the present invention.

FIG. 7 is a diagram illustrating the concept of conventional dead reckoning navigation and map matching.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wheel speed sensor 2 Direction sensor 3 Vehicle signal processing device 4 Micro map matching position detecting device 5 Display 6 Current position 7 Road 8 CD-ROM 9 Reliability evaluation device 10 Travel locus recording device 11 Macro map matching position detecting device 20 Antenna 21 GPS receiver

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-100418 (JP, A) JP-A-2-275310 (JP, A) JP-A-1-140015 (JP, A) JP-A-2- 296172 (JP, A) JP-A-4-213019 (JP, A) JP-A-4-290916 (JP, A) JP-A-6-102048 (JP, A) JP-A-6-77123 (JP, A) JP-A-2-33316 (JP, U) JP-A-6-7009 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 21/00 G08G 1/0969

Claims (3)

(57) [Claims] 1. A vehicle position detecting device for detecting a current position of a running vehicle, wherein the current position of the vehicle is calculated based on a signal representing a running vector according to the running of the vehicle, and is stored in advance. First position detecting means for performing local map matching with the road data to correct the calculated current position on the road; and reliability evaluation for evaluating the reliability of the current position corrected by the first position detecting means. Means for correcting the current position based on global position data when the reliability of the current position by the reliability evaluation means is lower than a predetermined reference and the number of correction candidate positions is equal to or more than a reference value. And a second position detecting means for detecting the vehicle position. 2. The second position detecting means responds to a vehicle signal, creates a pattern data representing a traveling locus by synthesizing a traveling vector, and performs pattern matching with road data stored in advance. The vehicle position detecting device according to claim 1, wherein the current position is corrected. 3. The vehicle position detecting device according to claim 1, wherein said second position detecting means receives a radio wave from a GPS satellite and corrects a current position.