JP4636723B2 - Navigation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a navigation apparatus that communicates with a network navigation center and receives map information from the center. In the following, “navigation” is abbreviated as “navigation”.
[0002]
[Prior art]
A communication type navigation system has been proposed in which communication is performed between a network navigation center and a navigation device, and map information is transmitted from the center to the navigation device. In this communication-type navigation system, the center side has a map database (DB) and a guide route creation function. When the center receives the vehicle position and the coordinates of the destination from the navigation device, the center creates a guidance route and returns map information displaying the guidance route and the vehicle location to the navigation device. The navigation device uses this map information to display a map, a travel route, and the vehicle position on the display screen.
[0003]
Thereby, the processing load of the navigation device is reduced, and the latest map information can always be obtained by managing the map DB in the center.
In this communication type navigation system, the map transmitted from the center to the navigation device is a picture file format map (raster map).
[0004]
[Problems to be solved by the invention]
In a conventional navigation system using a device in which a DVD or CD is mounted on a vehicle, even if the vehicle position measured by a GPS system or the like includes an error, an accurate position is displayed by a map matching method. Position accuracy can be improved. This is because the map information in the vector format is used. On the other hand, in the above communication type navigation system, a map in the picture file format is used in order to reduce the amount of data transmitted from the center to the navigation device. For this reason, the position accuracy improvement technique by the map matching method cannot be used.
[0005]
Therefore, in the navigation device of the communication type navigation system, even though the vehicle is traveling on the guidance route, it is displayed on the display screen as if traveling on a place other than the route due to an error in current position measurement. Is done. This is not only difficult for the user to use, but also shows a wrong guide route, which degrades the performance of the navigation system itself.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a navigation device that can improve position accuracy regardless of the format of map information in a navigation system.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, in the present invention, the navigation apparatus that receives map information in the form of a picture file from the center by communicating with the network navigation center, detects the detected vehicle position and the guidance route. The vehicle position correction means for correcting the position on the guidance route closest to the detected vehicle position as the vehicle position, a map obtained from the received map information, the guidance route, and the corrected vehicle position Navigation function management means for displaying the information on the screen, and the guide route is transmitted from the center as vector data. Is displayed, the vehicle position display is stopped.
The present invention has been made to achieve the above object. The navigation apparatus of the present invention is a navigation apparatus that receives map information in a picture file format from the center by communicating with a network navigation center, and compares the detected vehicle position with a guide route. And a vehicle position correcting means for correcting the position on the guide route closest to the detected vehicle position as the vehicle position.
[0008]
According to the present invention, even if the vehicle position is detected to be out of the guide route due to a measurement error, the detected vehicle position can be sucked into the nearest guide route (in this specification, This suction process is called “route matching”.) Thereby, even if the map information received from the center is in the picture file format, the position accuracy of the vehicle position can be improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention 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 of FIG. 1, the transmission / reception unit 2 performs transmission / reception 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 a process for navigation for each in-vehicle terminal 12 based on the stored data.
[0010]
The navigation guidance management unit 4 manages the guidance information creation unit 5, the route calculation unit 6, and the image creation unit 7 based on the data received from the in-vehicle terminal 12. The guide 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, and create guide information and guide route information. Performs computation and image creation. In the map DB 8, map information is stored in a vector format.
[0011]
The created guidance information, guidance route, and image are transmitted from the transmission / reception unit 2 to the corresponding in-vehicle terminal 12 via the terminal management unit 3.
In the in-vehicle terminal 12 in FIG. 2, the transmission / reception unit 13 performs transmission / reception with the center 1 via a mobile phone line, road-to-vehicle communication, beacon, or wireless communication. The map information received from the center 1 is 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, etc. is input from the vehicle information input unit 17 to the navigation function management unit 18.
[0012]
The navigation function management unit 18 transmits the vehicle information obtained from the vehicle information input unit 17 and the data input by the user from the input unit 19 from the transmission / reception unit 13 to the center 1. Further, when map information or the like is received from the center 1, it is stored in the storage unit 16.
Further, 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. To do. The guidance information management unit 20, the route management unit 21, and the image management unit 22 read map information from the storage unit 16 based on the vehicle position in the vehicle information, create a map image, a guidance route, and guidance information, and display them. And output from the output unit 23 such as a speaker.
[0013]
The own vehicle position correcting unit 24 corrects the own vehicle position when the own vehicle position deviates from the route due to a GPS measurement error. Hereinafter, the process of the vehicle position correcting unit 24 will be described.
FIG. 3 shows the principle of the vehicle position correction, and FIG. 4 is a flowchart showing the operation of the vehicle position correction unit 24.
[0014]
FIG. 3A shows the relationship between the guide route and the position detection point when the vehicle position is not corrected. If there is a measurement error in the GPS system that measures the vehicle position, the current position mark 31 and past position detection points 41 to 45 are displayed on the screen even if the vehicle is actually traveling on the guidance route 32. It is displayed off the route 32.
For the position correction process, the vehicle position correction unit 24 extracts the coordinates of the vehicle position obtained from the GPS (S1 in FIG. 4). The coordinates are compared with the guide route in the map information (S2). Here, the guide routes to be compared are extracted from the map in the picture file format. Specifically, color data indicating the guidance route is extracted from the map information, and the coordinates of the place closest to the vehicle position are obtained.
[0015]
Of the map information transmitted from the center 1 to the in-vehicle terminal 12, only the guide route 32 can be transmitted as vector data. In this case, the amount of transmission data from the center 1 to the in-vehicle terminal 12 is not increased so much, and the vehicle position can be corrected with higher accuracy using vector data.
Next, it is determined whether or not the shortest distance between the vehicle position coordinates and the guide route exceeds 200 m (S3). This 200 m is the maximum GPS error, and if the vehicle position exceeds 200 m and deviates from the guide route 32, the vehicle position is not corrected. Therefore, if it exceeds 200 m, the position correction process is terminated. As a result, it is possible to prevent the vehicle from being displayed on the guide route 32 even though it is actually off the guide route.
[0016]
If it is within 200 m, the vehicle position is corrected to the position closest to the guidance route (S4). As a result, each of the position detection points 41 to 45 is sucked vertically into the guide route 32 (route matching) as indicated by an arrow 46 in FIG. As a result, the position detection points 41 to 45 and the current position mark 31 are displayed on the guide route 32 on the screen of the output unit 23 as shown in FIG. Further, based on the corrected own vehicle position, an enlarged map display and voice guidance of the intersection can be performed.
[0017]
As described above, according to this example, even when the vehicle position is not accurately measured due to a GPS measurement error, the position is corrected by a simple method and the position accuracy of the navigation system is improved. Can be made.
Further, the embodiment described above can be further variously modified.
Even when NO is determined in step S3 in FIG. 4 and the suction is released, the suction can be performed when the user operates a button (not shown) provided on the input unit 19.
[0018]
When route matching is performed in step S4 of FIG. 4, as shown in FIG. 3C, the vehicle may run backward from the previous point 43 as shown by point 44. In this case, as shown in (D), the vehicle position mark 31 is not moved to the point 44 that appears to run backward, but remains at the previous point 43 until the next point 45 is detected. To do. When the reverse running distance exceeds 200 m, it may be determined that reverse running has actually occurred and the vehicle position mark 32 may be moved.
[0019]
By storing several points of the corrected vehicle position in the storage unit 16 and updating them, the latest travel history can be left. The detected position may be corrected using this travel history. In particular, when the vehicle stops or travels at a low speed, the detection position flutters due to measurement errors. In this case, when it is detected that the vehicle speed is below a certain level, the traveling direction is determined from the traveling history, thereby preventing the position display from flapping.
[0020]
At the start of guidance by navigation, the travel history and the vehicle position are transmitted to the center, and the vehicle position is corrected by the map matching method at the center, and the result is used to further improve the position accuracy. it can. During this time, the route matching function in the in-vehicle terminal 12 is stopped.
5 shows a modification of the center of FIG. 1, and FIG. 6 shows a modification of the in-vehicle terminal 12 of FIG. The illustrated example is a communication type navigation using broadcasting. Only differences from FIG. 1 and FIG. 2 will be described below.
[0021]
In this example, data is transmitted from the in-vehicle terminal 12 to the center 1 through a public line, an Internet line, or wireless communication from a mobile phone line, road-to-vehicle communication, beacon, or wireless communication. Data transmission from the center 1 to each in-vehicle terminal 12 is broadcast from a broadcasting station such as a ground station or a communication satellite, and is received by each in-vehicle terminal 12 through an antenna.
[0022]
【The invention's effect】
According to the present invention, in the navigation system, the position accuracy can be improved regardless of the format of the 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.
3 is a diagram illustrating the principle of own vehicle position correction processing of the in-vehicle terminal in FIG. 2;
4 is a flowchart showing an operation of a vehicle position correction unit of the in-vehicle terminal in FIG.
FIG. 5 is a diagram showing a modification of FIG. 1;
6 is a diagram showing a modification of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Network navigation center 2 ... Transmission / reception part 3 ... Terminal management part 4 ... Navigation guidance management part 5 ... Guidance information creation part 6 ... Route calculation part 7 ... Image creation part 8 ... Map DB
DESCRIPTION OF SYMBOLS 9 ... Map management part 12 ... In-vehicle terminal 13 ... Transmission / reception part 14 ... Memory management part 15 ... Reception information management part 16 ... Storage part 17 ... Vehicle information input part 18 ... Navigation function management part 19 ... Input part 20 ... Guidance information creation part DESCRIPTION OF SYMBOLS 21 ... Route calculation part 22 ... Image preparation part 23 ... Output part 24 ... Own vehicle position correction part 31 ... Current position mark 32 ... Guide route 33 ... Traveling track 34 ... Transmission part 35 ... Reception part 41, 42, 43, 44, 45 ... position detection point 46 ... arrow

Claims (2)

In a navigation device that receives picture file format map information from the center by communicating with a network navigation center,
Comparing the guide route and the detected vehicle position, a vehicle position correcting means for correcting the position on the nearest guide route on the vehicle position said detected as vehicle position,
Comprising a navigation function management unit that displays described above with the map obtained from the received map information and the guide route correcting the vehicle position on the screen, and
The guide route is transmitted from the center as vector data ,
The vehicle position correction means stops the vehicle position display when the corrected vehicle position indicates reverse running,
A navigation device characterized by that. The navigation apparatus according to claim 1 , wherein the vehicle position correction unit does not perform the correction process when a reverse running distance exceeds a certain range.

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