JP2002310690A - Position precision improving method for navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve position accuracy, regardless of the form of map information in a navigation system. SOLUTION: An on-vehicle terminal transmits present position 11 and traveling histories 21-25 to a center. The traveling histories include GPS history C, vehicle speed history E, and gyro history F, and at the center, a route similar to the pattern of traveling history is retrieved near the present position by pattern matching. The traveling track and the present position are displayed on the route of the retrieval result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for improving position accuracy in a navigation system. The present invention
Further, the present invention relates to a method for improving position accuracy in a communication type navigation system in which communication is performed between a navigation device and a network navigation center and map information is transmitted from the center to the navigation device. In the following, “navigation” is abbreviated as “navi”.

[0002]

2. Description of the Related Art There has been proposed a communication type navigation system for communicating between a navigation device and a network navigation center and transmitting map information from the center to the navigation device. In this communication type navigation system, the center uses a map database (D
B) and a guide route creation function. When receiving the vehicle position and the coordinates of the destination from the navigation device, the center creates a guidance route and returns map information indicating the guidance route and the vehicle position to the navigation device. The navigation device uses the map information to display a map, a travel route, and a position of the vehicle on a display screen.

[0003] Thus, the processing load on the navigation apparatus can be reduced, and the map DB can be managed in the center, so that the latest map information can always be obtained. In this communication type navigation system, the map transmitted from the center to the navigation device is a map in a picture file format (raster map).

[0004]

SUMMARY OF THE INVENTION Conventionally, DVDs are mounted on vehicles.
Or, in a navigation system using a device equipped with a CD, even if an error is included in the position of the vehicle measured by a GPS system or the like, an accurate position is displayed by a map matching method to improve the position accuracy. Can be. This is due to the use of map information in vector format. On the other hand, the communication type navigation system uses a map in a picture file format in order to reduce the amount of data transmitted from the center to the navigation device. For this reason, the technology for improving the position accuracy by the map matching method cannot be used.

[0005] Therefore, in the communication type navigation device, even though the vehicle is traveling on the guide route, it is displayed on the display screen as if the vehicle is traveling other than the route due to an error in the current position measurement. Is done. This is not only difficult for the user to use, but also results in an incorrect guidance route, and the performance of the navigation system itself deteriorates.

An object of the present invention is to improve position accuracy in a navigation system regardless of the format of map information.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. The position accuracy improving method in the navigation system according to the present invention is a navigation system that detects a current position and displays the current position on a map, and searches for a route on a map corresponding to the current position and the latest travel history. The current position is displayed on the route that has been set.

[0008] The latest travel history includes a history of a measured position by GPS, a history of vehicle speed, a history of gyro, and the like. In the case of a GPS history, a traveling locus can be obtained by connecting several vehicle positions detected in the past. In the case of the history of the vehicle speed, since the vehicle speed increases on a straight road and decreases on a curve, the shape of the trajectory that has traveled can be determined. According to the history of the gyro, the shape of the trajectory can be determined based on straight traveling, right turning, left turning and the like.

According to the present invention, the trajectory of the vehicle traveling from the traveling history is determined, and a pattern corresponding to the above-described trajectory history is searched for in a route pattern close to the own vehicle position. Then, by selecting the route of the closest pattern, the position of the own vehicle on the route can be determined. Thus, even if the measured current position includes an error, the current position can be indicated on a correct route of the map information.

The position accuracy improving method in the navigation system according to the present invention is particularly suitable for the above-mentioned communication type navigation system. In the communication type navigation system, a map in a picture file format is sent to the navigation device. In this case, the latest travel history is transmitted from the navigation device to the center together with the position of the vehicle. The center searches for a route on the map corresponding to the received current position and the latest travel history, displays the current position on the searched route, and returns map information including the current position to the navigation device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a position accuracy improving method in a navigation system according to the present invention is applied to a communication type navigation system will be described with reference to the drawings. FIG. 1 shows the configuration of the network navigation center 1, and FIG. 2 shows the configuration of the in-vehicle terminal 12 (navigation device). The illustrated example is an example using two-way communication.

In the center 1 shown in FIG.
Transmission and reception are performed with the in-vehicle terminal 12 via a public line, an Internet line, or wireless communication. Data received from the plurality of in-vehicle terminals 12 is stored in the terminal management unit 3 for each in-vehicle terminal 12. The terminal management unit 3 manages navigation processing for each in-vehicle terminal 12 based on the stored data.

The navigation guide management unit 4 manages a guide information creation unit 5, a route calculation unit 6, and an image creation unit 7 based on data received from the on-board terminal 12. Guidance information creation unit 5,
The route calculation unit 6 and the image creation unit 7 read map information from the map DB 8 via the map management unit 9 based on the data received from the in-vehicle terminal 12, create guide information, calculate a guide route, and create an image. Execute. In the map DB 8, map information is stored in a vector format.

The created guide information, guide route, and image are transmitted from the transmission / reception unit 2 to the corresponding on-vehicle terminal 12 via the terminal management unit 3. The vehicle position correction unit 10 corrects the current position of the vehicle based on the current position of the vehicle, travel history, and map information. The operation of the vehicle position correction unit 10 will be described later. In the in-vehicle terminal 12 of FIG.
It transmits and receives to and from the center 1 via a mobile phone line, road-vehicle communication, beacon, or wireless communication. The map information and the like received from the center 1 are stored in the storage unit 16 via the transmission / reception unit 13, the memory management unit 14, and the reception information management unit 15.
Vehicle information obtained from a GPS, a gyro, a speedometer, and the like is input from the vehicle information input unit 17 to the navigation function management unit 18. Further, the vehicle information is stored in the storage unit 16 every time measurement is performed, and a predetermined number of vehicle information is updated as the latest traveling history.

The navigation function management unit 18 includes a vehicle information input unit 1
The vehicle information obtained from the communication unit 7, the travel history, and the data input by the user from the input unit 19 are transmitted from the transmitting / receiving unit 13
Send to The navigation function management unit 18 manages the guidance information management unit 20, the route management unit 21, and the image management unit 22 based on the map data received from the center 1 and the vehicle information input from the vehicle information input unit 17. I do. The guidance information management unit 20, the route management unit 21, and the image management unit 22 read the map information from the storage unit 16 based on the own vehicle position, and output the map image, the guidance route, and the guidance information to the output unit 23 such as a display and a speaker. Output from

The operation of the vehicle position correcting section 10 of the center 1 shown in FIG. 1 will be described below. FIG. 3 shows the principle of vehicle position correction, and FIG. 4 is a flowchart showing the processing of the vehicle position correction unit 10. FIG. 3 (A) shows a state where the vehicle is actually traveling on the route 32. If there is a measurement error in the GPS system that measures the position of the vehicle in the vehicle,
If the position is not corrected, (B)
Is displayed. The current position mark 31 of the vehicle is located at a position deviating from the guide route 32, and is displayed as if the vehicle is traveling outside the guide route 32.

In FIG. 4, the vehicle position correction unit 10 first extracts a map of the surroundings based on the current position received from the vehicle terminal 12 (S1). Next, the traveling history is extracted from the data received from the vehicle-mounted terminal 12 (S2). Here, when the traveling history is the GPS history, as shown in FIG. 3C, the traveling locus 33 is obtained by connecting the position detection points 41 to 45 detected by GPS (S3). Then, a shape matching the pattern of the traveling locus 33 is searched from the guidance route 32 near the current position 31 (S4).

As a result, when the guide route 32 having the most similar pattern is searched, the corrected current position mark 31 is displayed at the position closest to the current position detected by the GPS as shown in FIG. 3D. FIG. 3E shows an example where the traveling history is a vehicle speed history. Here, the point 4 where the vehicle speed is detected
It is assumed that the vehicle speed at 1 to 45 is as shown in (E). That is, at points 41, 43, and 45 on a straight road, the vehicle speed is high, and at the curve points 42 and 44, the vehicle speed is low. In this case, the traveling locus obtained from the vehicle speed is the same as in (D).

FIG. 3F shows an example in which the traveling history is a gyro history. Here, the point 4 detected by the gyro
It is assumed that the histories 1 to 45 are as shown in FIG. That is, at the point of the curve, the gyro history detects that the vehicle has turned left or right. In this case, the traveling locus obtained from the gyro is the same as that shown in (D). As described above, according to the present embodiment, since the center 1 performs necessary processing such as route calculation, the load of the navigation processing on the vehicle-mounted terminal 12 is reduced. In addition, since the current position is corrected based on the travel history, even if there is an error in the detection of the position of the vehicle by the in-vehicle terminal 12, the position accuracy can be improved. In addition, the position accuracy can be further improved by using a conventionally used map matching method.

When the current position or the running history received from the in-vehicle terminal 12 is measured by GPS, the position accuracy can be further improved by performing D-GPS processing in the center 1. Furthermore, when it is determined that the vehicle is traveling at a constant speed based on the traveling history, the time required for processing such as detection of the position of the own vehicle in the in-vehicle terminal 12 is anticipated, and a predetermined time ahead. It is also possible to calculate the expected position and transmit it to the in-vehicle terminal. As a result, the current position can be accurately displayed without being affected by the time delay due to the processing.

Note that the position accuracy improving method of the present invention is not limited to the processing performed in the center 1. Even in a conventional navigation system in which a CD and a DVD are mounted on the in-vehicle terminal 12, the own vehicle position can be corrected based on the running history, and the position accuracy can be similarly improved. FIG.
6 shows a modification of the center in FIG. 1, and FIG. 6 shows a modification of the vehicle-mounted terminal in FIG. The illustrated example is a communication type navigation using broadcasting. Hereinafter, only differences from FIG. 1 and FIG. 2 will be described.

In this example, data is transmitted from the vehicle-mounted terminal 12 to the center 1 via a mobile phone line, road-vehicle communication, beacon, or wireless communication via a public line, the Internet line, or wireless communication. From the center 1 to each in-vehicle terminal 1
2 is transmitted from a broadcasting station such as a ground station or a communication satellite, and received by each in-vehicle terminal 12 via an antenna.

[0023]

According to the present invention, in a communication type navigation system, the positional accuracy can be improved regardless of the format of map information.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a center constituting a navigation system of the present invention.

FIG. 2 is a configuration diagram of an in-vehicle terminal constituting the navigation system of the present invention.

FIG. 3 is a diagram illustrating the principle of a vehicle position correction process in the center of FIG. 1;

FIG. 4 is a flowchart illustrating an operation of a vehicle position correction unit of the center of FIG. 1;

FIG. 5 is a diagram showing a modification of FIG. 1;

FIG. 6 is a diagram showing a modification of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Network navigation center 2 ... Transmission / reception part 3 ... Terminal management part 4 ... Navigation guidance management part 5 ... Guide information creation part 6 ... Route calculation part 7 ... Image creation part 8 ... Map DB 9 ... Map management part 10 ... Vehicle position correction Unit 12: In-vehicle terminal 13 ... Transmission / reception unit 14 ... Memory management unit 15 ... Reception information management unit 16 ... Storage unit 17 ... Vehicle information input unit 18 ... Navigation function management unit 19 ... Input unit 20 ... Guidance information management unit 21 ... Route management Unit 22 image management unit 23 output unit 31 current position mark 32 guide route 33 traveling trajectory 34 transmission unit 35 reception unit 41, 42, 43, 44, 45 GPS position detection point

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Sako 1-2-28 Goshodori, Hyogo-ku, Kobe-shi, Hyogo F-term in Fujitsu Ten Limited (reference) 2C032 HB22 HC08 HD26 2F029 AA02 AB01 AB03 AB07 AC02 AC14 AC19 AD01 5H180 AA01 BB02 BB04 CC02 CC12 CC30 FF04 FF07 FF13 FF22 FF27 FF33

Claims (11)

[Claims] 1. A navigation system for detecting a current position and displaying the current position on a map, searching a route on a map corresponding to the current position and the latest travel history, and displaying the current position on the searched route. And displaying the position accuracy in the navigation system. 2. The position accuracy improving method in a navigation system according to claim 1, wherein the travel history is a history of a position measured by GPS. 3. The method according to claim 1, wherein the travel history is a history of vehicle speed. 4. The method according to claim 1, wherein the travel history is a gyro history. 5. A navigation system for transmitting map information from a network navigation center to a navigation device by communicating between the network navigation center and the navigation device, wherein the navigation device records the latest travel history together with the position of the vehicle. Transmitting to the center, the center searches for a route on a map corresponding to the received current position and the latest travel history, displays the current position on the searched route, and displays map information including the current position. A method for improving position accuracy in a navigation system, wherein the method is transmitted to the navigation device. 6. The position accuracy improving method in a navigation system according to claim 5, wherein the travel history is a history of a position measured by GPS. 7. The method according to claim 5, wherein the traveling history is a vehicle speed history. 8. The method according to claim 5, wherein the travel history is a gyro history. 9. The method according to claim 5, wherein the center performs a map matching process on the current position and the map database to improve the position accuracy. 10. The self-vehicle position is detected by GPS, and the center is located at a distance D from the self-vehicle position.
-The GPS processing is applied to improve the position accuracy.
3. A method for improving position accuracy in a navigation system according to item 1. 11. A position accuracy improving method in a navigation system, wherein the center transmits a predicted navigation device position ahead of the navigation device by a predetermined time to the navigation device when a speed component of the navigation device keeps a constant amount.