JP2006275564A - Navigation device and navigation method - Google Patents

Abstract

In a navigation device having a map matching function, the position of a vehicle is accurately displayed when the vehicle is traveling in an area where map data is not updated.
When traveling in an area updated to the latest map data, normal map matching processing is performed, and when a vehicle is traveling in an area not updated to the latest map data, While reducing the utilization of a map matching process, the detection accuracy of the own vehicle position by the GPS receiver 1 is improved. Thereby, the position of the vehicle can be accurately displayed.
[Selection] Figure 1

Description

  The present invention relates to a navigation device having a map matching function and a navigation method.

  Conventionally, by using the feature that an automobile normally travels on a road, even if the vehicle position display mark is off the road due to a detection error of the vehicle position, the vehicle is forcibly placed on a nearby road. A navigation device having a map matching function that corrects the position and displays a mark of the vehicle position is known (see Patent Document 1).

JP 2004-226341 A

  However, in a navigation device provided with map data that can be partially updated, if map matching processing is performed when a vehicle is traveling in an area where map data is not updated, unupdated map data When traveling on a non-existing road, there arises a problem that the vehicle position is corrected on a road different from the actual road.

  The navigation device and the navigation method according to the present invention detect the current location of a vehicle, and perform vehicle position correction by map matching based on the detected vehicle position and map data that can be partially updated. Based on the detected vehicle position, it is determined whether or not the map data of the area where the vehicle is traveling is new map data, and the map data of the area where the vehicle is traveling is not new map data. When the determination is made, the use frequency of the vehicle position correction process by map matching is reduced, and the detection accuracy of the vehicle position is increased.

  According to the navigation device and the navigation method of the present invention, if it is determined that the map data of the area where the vehicle is traveling is not new map data, the frequency of use of the vehicle position correction processing by map matching is reduced, and the vehicle position Therefore, it is possible to prevent the vehicle position from being corrected on a road different from the actual road based on the unupdated map data.

  FIG. 1 is a diagram illustrating a configuration of a navigation device according to an embodiment. The navigation device in one embodiment includes a GPS receiver 1, a map database 2, an operation switch 3, a display 4, a speaker 5, a communication device 6, and a navigation calculation control unit 10.

  The GPS receiver 1 receives signal radio waves from GPS satellites at predetermined intervals and detects the current location of the vehicle. The map database 2 stores map data. This map data represents route calculation data used to calculate the recommended route, route guidance data used to guide the vehicle to the destination according to the recommended route, such as intersection name and road name, and road shape. It includes road data, background data representing map shapes other than roads, such as coastlines, rivers, railways, buildings, and POI (Point Of Interest) data. The POI data includes data such as names, positions, types, and telephone numbers of various facilities.

  The map data stored in the map database 2 can be updated with a rectangular area of a predetermined size called a mesh as one unit. The data can be updated using, for example, a CD-ROM in which the latest map data is stored. Thus, by partially updating the map data in units of meshes, only the map data of the area where the data is updated or the map data of the area frequently used by the user is efficiently rewritten to the latest map data. be able to.

  The operation switch 3 is a switch for the user to perform various operations such as various operations on the road map display screen, destination setting, and facility search. The display 4 displays a map around the vehicle, a current location of the vehicle, a route to the destination, and the like based on an instruction from a navigation calculation control unit 10 described later. The speaker 5 outputs voice guidance such as route guidance to the destination. The communication device 6 exchanges various data by performing wireless communication with an information center that owns various data to be distributed to the vehicle.

  The navigation calculation control unit 10 includes a CPU, a ROM, a memory, and the like, and performs overall navigation system processing such as processing for displaying the current location of the vehicle on a map and processing for calculating an optimum route to the destination. The process of displaying the current location of the vehicle on the map is performed based on the current location of the vehicle detected by the GPS receiver 1, but if the current location of the vehicle is off the road on the map data, theoretically Map matching processing is performed to correct the vehicle position on a road that is considered to be traveling. Since map matching is a known process, detailed description thereof is omitted here.

  The navigation calculation control unit 10 also periodically communicates with the information center that owns the latest map data via the communication device 6 to store the map data stored in the map database 2. Among these, a mesh (area) updated to the latest data and a mesh (area) not updated to the latest data are identified. The determination result of whether or not the latest map data is updated is stored in a memory (not shown).

  In the navigation device according to the embodiment, it is determined whether or not the area in which the vehicle is traveling is an area that has been updated to the latest map data, and travels in an area that has not been updated to the latest map data. If it is, the use frequency of the map matching process is reduced and the vehicle position detection accuracy by the GPS receiver 1 is improved. Improvement of the vehicle position detection accuracy by the GPS receiver 1 is performed by shortening the interval of receiving signal radio waves from GPS satellites and increasing the frequency of radio wave reception.

  FIG. 2 is a flowchart showing the contents of processing performed by the navigation device in one embodiment. When the navigation device is turned on and the user operates the operation switch 3 to issue a command to display the vehicle position on the display 4, the navigation calculation control unit 10 starts the process of step S10.

  In step S10, the vehicle position information detected by the GPS receiver 1 is acquired, and the process proceeds to step S20. In step S20, the area where the vehicle is traveling is identified based on the vehicle position information acquired in step S10 and the map data stored in the map database 2, and the identified area is the latest map data. It is determined whether the area has been updated. As described above, the navigation calculation control unit 10 periodically determines whether or not the map data stored in the map database 2 is updated to the latest map data, and stores the determination result in the memory. I am letting. Therefore, based on the update determination result stored in the memory, it is determined whether or not the mesh map data including the current location of the vehicle is the latest map data. If it is determined that the map data of the area (mesh) in which the vehicle is traveling has been updated to the latest map data, the process proceeds to step S30. If it is determined that the map data has not been updated to the latest map data, the process proceeds to step S40.

  In step S30, normal map matching processing is performed. On the other hand, in step S40, the utilization of the map matching process is reduced to improve the position detection accuracy by the GPS receiver 1. As described above, the position detection accuracy is improved by shortening the interval at which the GPS receiver 1 receives the signal radio wave from the GPS satellite and increasing the radio wave reception frequency. The vehicle position obtained by the process of step S30 or step S40 is displayed on the display 4 together with the map data.

  According to the navigation device in one embodiment, when a vehicle travels in an area that has not been updated to the latest map data, the degree of use of the map matching process is reduced, and the position of the vehicle by the GPS receiver 1 is reduced. Improve detection accuracy. As a result, when the vehicle is traveling on a road that does not exist on the map data stored in the map database 2 but actually exists, the map matching process moves the vehicle position to another road. It is possible to prevent the correction. Moreover, since the position detection accuracy by the GPS receiver 1 is improved instead of reducing the utilization of the map matching process, it is possible to prevent the display accuracy of the vehicle position from being lowered.

  In the navigation device in one embodiment, the detection accuracy of the vehicle position is improved by shortening the interval of receiving signal radio waves from GPS satellites and increasing the frequency of radio wave reception. Here, regardless of whether the map data has been updated to the latest map data, it may be possible to always increase the frequency of reception of radio waves from GPS satellites. Based on this, the number of processes for detecting the current location of the vehicle increases, and thus the processing load increases. However, the frequency of receiving signal radio waves from GPS satellites is increased only when the vehicle travels in an area that has not been updated to the latest map data, as in the navigation device in one embodiment. There is no processing load problem.

  The present invention is not limited to the embodiment described above. For example, when traveling in an area not updated to the latest map data, the travel route based on the vehicle position detected by the GPS receiver 1 is on the road of the map data stored in the map database 2. There may be no. In such a case, if the travel route data when traveling on a place other than a road is transmitted to the information center via the communication device 6 and the data is accumulated in the information center, the information center side A new road or the like can be grasped, and for example, it can be used when creating map data including a new road.

  In the above-described embodiment, an example in which the current position of the vehicle is detected using GPS navigation is described. However, the position of the vehicle can also be detected by other methods. FIG. 3 is a diagram showing a configuration of a navigation device that detects the current location of a vehicle by using both GPS navigation and autonomous navigation. This navigation device includes a gyro sensor 11 and a vehicle speed sensor 12 in addition to the configuration of the navigation device shown in FIG. The navigation calculation control unit 10, together with the vehicle position detected by the GPS receiver 1, travels in a tunnel or the like where radio waves cannot be received, and the vehicle traveling direction detected by the gyro sensor 11 and the vehicle speed sensor 12. Based on the vehicle speed detected by the above, the current location of the vehicle is calculated. Even in this case, when the vehicle travels in an area that has not been updated to the latest map data, the utilization of the map matching process is reduced, and the accuracy of at least one of the gyro sensor 11 and the vehicle speed sensor 12 is reduced. By improving the above, the position detection accuracy of the vehicle can be improved. The method for detecting the current location of the vehicle is not limited to these methods.

  In the above-described embodiment, when the vehicle travels in an area that has not been updated to the latest map data, the degree of use of the map matching process is reduced and the detection accuracy of the vehicle position by the GPS receiver 1 is increased. Improved. However, when the map data is updated, if the data has not changed much, for example, even if the map data is one version before, the normal map matching process is performed without reducing the utilization of the map matching process. You may make it perform.

  The map data has been described as being able to update a mesh, which is a rectangular area of a predetermined size, as a unit. However, if the data can be partially updated, it is not limited to the method of updating the mesh as a unit. Absent.

  The navigation device is not limited to being mounted on a four-wheeled vehicle, and may be mounted on a large vehicle such as a bus / truck or may be mounted on a two-wheeled vehicle.

  Note that the present invention is not limited to the configurations in the above-described embodiments as long as the characteristic functions of the present invention are not impaired.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the GPS receiver 1 constitutes current location detection means, the map database 2 constitutes map data storage means, and the navigation calculation control unit 10 constitutes position correction means, data update determination means, and control means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the structure of the navigation apparatus in one embodiment. The flowchart which shows the processing content performed by the navigation apparatus in one embodiment The figure which shows the modification structural example of a navigation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... GPS receiver, 2 ... Map database, 3 ... Operation switch, 4 ... Display, 5 ... Speaker, 6 ... Communication apparatus, 10 ... Navigation calculation control part

Claims (4)

Current location detection means for detecting the current location of the vehicle;
Map data storage means for storing map data that can be partially updated,
Position correction means for performing vehicle position correction by map matching based on the position detected by the current location detection means and map data stored in the map data storage means;
Based on the current location detected by the current location detection means, it is determined whether the map data of the area where the vehicle is running is new map data among the map data stored in the map data storage means. Data update determination means;
When it is determined by the data update determination means that the map data of the area where the vehicle is traveling is not new map data, the frequency of use of the vehicle position correction processing by the position correction means is reduced and the current location detection is performed. And a control means for increasing the accuracy of detection of the current location by the means. The navigation device according to claim 1, wherein
The current location detection means receives a radio wave from a GPS satellite and detects the current location of the vehicle based on the received radio wave,
The navigation device according to claim 1, wherein the control means increases the detection accuracy of the current location by increasing the frequency at which the current location detection means receives radio waves from GPS satellites. The navigation device according to claim 1, wherein
The present location detecting means includes a traveling direction detecting means for detecting the traveling direction of the vehicle and a vehicle speed detecting means for detecting the speed of the vehicle, and is detected by the traveling direction detected by the traveling direction detecting means and the vehicle speed detecting means. Based on the vehicle speed, the current location of the vehicle is calculated,
The navigation device according to claim 1, wherein the control means increases the detection accuracy of at least one of the vehicle speed detection means and the traveling direction detection means, thereby increasing the detection accuracy of the current location. In a navigation method for detecting the current location of a vehicle, and correcting the vehicle position by map matching based on the detected vehicle position and map data that can be partially updated,
Based on the detected vehicle position, determine whether the map data of the area where the vehicle is traveling is new map data,
Navigation characterized in that if the map data of the area where the vehicle is traveling is not new map data, the frequency of use of the vehicle position correction processing by map matching is decreased and the detection accuracy of the vehicle position is increased. Method.

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