JP3418080B2 - Map matching method for car navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses GPS (Global P.
ositioning System), etc., regarding the map matching method of the vehicle-mounted navigation device that corrects the current position of the vehicle, especially whether the vehicle has entered the parking lot (including parks and shops that have parking lots; the same applies below) The present invention relates to a map matching method for a vehicle-mounted navigation device having a function of detecting whether or not it is present.

[0002]

2. Description of the Related Art An on-vehicle navigation system is a map data storage device such as a CD-ROM or an IC card recording map data, a monitor such as a liquid crystal display, a current position of a vehicle such as a gyro, a GPS and a vehicle speed sensor. It has a vehicle movement detection device for detecting the current azimuth, reads map data including the current position of the vehicle from the map data storage device, and draws a map image around the vehicle position on the monitor based on the map data. , The vehicle position mark (location) is displayed on the map image, and the map image is scroll-displayed according to the movement of the vehicle, or the map image is fixed on the screen and the vehicle position mark is moved. I try to know at a glance where I am currently driving.

In addition, a vehicle-mounted navigation device is usually equipped with a route guidance function that allows a user to easily travel to a desired destination without making a mistake on the road. According to this route guidance function, the route with the lowest cost connecting the starting point to the destination is automatically searched by using the map data by performing a simulation calculation such as horizontal search method or Dijkstra method, and the searched route is guided. It is stored as a route, and while driving, the guide route is drawn in a different color from the other roads on the map image and displayed thickly on the screen, or at a certain distance to the intersection where the vehicle should change the route on the guide route. When approaching inside, the user is guided to the destination by displaying an arrow indicating the route at an intersection where the route should be changed on the map image.

The cost is a value obtained by multiplying a road width, a road type (whether it is a general road or a highway, etc.), a constant according to a right turn, a left turn, or the like, a predicted travel time of a vehicle, etc. , Is a numerical representation of the degree of suitability as a guide route. Even if there are two routes with the same distance, the cost will be different depending on whether or not the user uses the toll road, whether the distance is prioritized or the time is prioritized.

A map stored in a map data storage device such as a CD-ROM has a longitude width of an appropriate size according to the scale level such as 1/12500, 1/25000, 1/50000 and 1/100000. It is divided into latitude widths, and roads and the like are stored as a coordinate set of vertices (nodes) represented by longitude and latitude. A road is formed by connecting two or more nodes, and a part connecting two nodes is called a road link. Further, the map data includes (1) a road layer including a road list, a node table, an intersection configuration node list, and the like, (2) a background layer for displaying roads, buildings, facilities, parks, rivers, etc. on the map screen, (3) Administrative division names such as municipalities,
It is composed of characters such as road names, intersection names and building names, and a character / symbol layer for displaying map symbols.

By the way, the vehicle position detection by GPS includes an error of about 200 m at maximum. Usually, the navigation device uses a map for correcting the vehicle position detected by the GPS, gyro, vehicle speed sensor, etc. by using the map data of the CD-ROM so that the vehicle position mark on the map screen traces the road accurately. A matching function is provided. For example, as shown in FIG. 6, it is assumed that the vehicle traveling on the road A turns left at the intersection B. Intersection B
Since the longitude and latitude of are stored in the CD-ROM,
The navigation device uses the longitude and latitude of the intersection B to correct the current position of the vehicle. Even after that, the navigation device corrects the current position of the vehicle detected by GPS so that the vehicle traces on the road C using the map data stored in the CD-ROM.

However, in the conventional map matching method, when the vehicle enters the parking lot, the vehicle position is forcibly matched with the road near the parking lot by recognizing that the vehicle has turned the road. There is. Then, when the vehicle moves next time, it takes time to adjust the vehicle position to the actual road, which confuses the user. In order to suppress such a problem, the conventional vehicle-mounted navigation device detects whether or not the vehicle has entered the parking lot as follows. That is, as shown in FIG. 7, after the vehicle bends at an intersection D and the vehicle position is corrected by map matching, (distance from the intersection D to the intersection E-detection error of the traveling distance from the intersection D) is more than The vehicle turns left within a small distance and polygonal area F
When entering, the navigation device determines that the vehicle has entered the parking lot and stops matching the vehicle position to the road link.

The polygonal area is data (polygon data) indicating the shape of a polygonal area included in the background information in the map data, and indicates a park, a vacant lot, a parking lot, and the like.

[0009]

However, according to the conventional map matching method, when the vehicle turns at an intersection, the vehicle position is matched with the coordinates of the intersection, and then the distance traveled by the vehicle and the accumulated error in the distance. It is necessary to calculate and calculate the position where the vehicle makes a right turn or a left turn, and determine whether the vehicle entered the polygonal area or made a right turn or a left turn on the road. Has the drawback of being large. Further, in the conventional method, since the detection error of the distance traveled between turning the intersection and turning the vehicle right or left is relatively large, whether the vehicle entered the parking lot or turned right or left on the road. There is a risk of making a wrong decision when making a decision.

From the above, the object of the present invention is to more accurately determine whether the vehicle has entered the parking lot or has turned right or left at the intersection, and the current position of the vehicle can be displayed more accurately on the screen. Another object of the present invention is to provide a map matching method for a vehicle-mounted navigation device that can reduce the load on the microcomputer.

[0011]

[Means for Solving the Problems] The above-mentioned problem is that the position data at the entrance and exit of the parking lot are stored in the map data storage means together with the road link data and the polygonal area data, and the signals sent from the satellite are used. The present position of the vehicle is detected, the detected position of the vehicle is map-matched to the position on the road link and displayed on the screen, and when the vehicle decelerates below a certain speed, the parking lot read from the map data storage means. Check the presence or absence of a parking lot entrance within a certain range from the current position of the vehicle using the position data of the entrance, and if there is a parking lot entrance within the certain range and the vehicle makes a right turn or a left turn, within the polygonal area When the vehicle enters, the map matching on the road link is stopped, which is solved by the map matching method of the vehicle-mounted navigation device. .

The operation of the present invention will be described below. In the map matching method of the vehicle-mounted navigation device of the present invention, the position data of the entrance and the exit of the parking lot are stored in the map data storage means, and the vehicle speed becomes a certain speed or less while traveling on the road, and When the vehicle turns right or left within a certain range from the entrance of the parking lot, it is determined that the vehicle has entered the parking lot. Accordingly, the navigation device can accurately determine whether the vehicle has entered the parking lot or has turned right or left at the intersection without performing complicated calculations. Further, when the vehicle starts traveling again, the display of the current position of the vehicle can be started quickly and accurately, and the reliability is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a vehicle-mounted navigation device that realizes a map matching method according to an embodiment of the present invention. Reference numeral 1 is a navigation device body composed of a microcomputer. Reference numeral 2 denotes a liquid crystal monitor, and the navigation device body 1 displays a map near the current position of the vehicle on the liquid crystal monitor 2 and displays a guide route from a departure place to a destination, a vehicle position mark, and other guidance information. To do.

Reference numeral 3 is a CD-ROM which stores map data composed of road layers, background layers, character / symbol layers and the like according to scales. A GPS receiver 4 detects the current position of the vehicle, the vehicle direction, the vehicle speed, and the like by satellite navigation. Reference numeral 7 denotes a gyro that detects a rotation angle of the vehicle, and 8 denotes a vehicle speed pulse detection unit that detects a vehicle speed pulse generated as the vehicle moves. Reference numeral 9 denotes a key operation unit provided with various keys for operating the navigation device.

The navigation device body 1 detects the current position, azimuth and speed of the vehicle based on the information obtained from the GPS receiver 4, the gyro 7 and the vehicle speed pulse detector 8 and, as the vehicle travels, Then, the position of the vehicle is matched with the road link using the map data. The road layer in the map data has the structure shown in FIG. The road list RDLT is made up of, for each road, data such as the road type, the total number of nodes forming the road, the positions of the nodes forming the road on the node table NDTB, and the road width to the next node. . The intersection constituent node list CRLT is, for each intersection on the map, a set of positions on the node table NDTB of the other end node of the link (referred to as an intersection constituent node) which is connected to the intersection.

The node table NDTB is a list of all nodes on the map, and coordinates (longitude and latitude) for each node.
And an identification flag indicating whether the node is an intersection, an entrance of a parking lot, or an exit of the parking lot. If the node is an intersection (if the intersection identification flag is "1"), the intersection constituent node list C
Pointer (Pn) that points to the position (Qi) on the RLT and is not an intersection (if the intersection identification flag is "0") points to the position of the road to which the node belongs on the road list
Etc. If the parking lot entrance flag of the node is “1”, it means that the coordinates of the node are also the coordinates of the parking lot entrance, and the parking lot exit flag is “1”.
If it is, it means that the coordinates of the node are also the coordinates of the parking lot exit. If the parking lot entrance and exit are common, both the parking lot entrance flag and exit flag are "1".
Becomes

FIG. 3 is an explanatory diagram showing a map image represented by road layers. In the figure, 12 is an intersection node, 1
3 is a parking lot entrance node, 14 is a parking lot exit node, 11
Indicates other simple nodes. Further, 15 indicates a polygonal area represented by the background layer, and 16 indicates a position mark of the vehicle. FIG. 4 is a flowchart showing the map matching method of this embodiment. Hereinafter, the map matching method according to the present embodiment will be described with reference to FIGS.

The navigation device detects the current position of the vehicle based on the information from the GPS receiver 4 while the vehicle is traveling on the road, and uses the map data stored in the CD-ROM 3. The detected vehicle position is map-matched on the road link. Then, along with the movement of the vehicle, the vehicle position mark 16 on the map image is moved along the road link (step 1).

The navigation device monitors the vehicle speed based on the information from the vehicle speed pulse detector 8 while the vehicle is being guided in this way. Then, when the vehicle speed falls below a certain value (for example, 20 km / h), it is checked whether or not the parking lot entrance node 13 exists within a certain range (for example, 10 to 20 m) from the current position of the vehicle (step). S
2, S3). When the parking lot entrance node 13 exists within a certain range in step S3 (YES), it is detected whether the vehicle turns right or left to enter the polygonal area 15 (steps S4 and S5).

When the vehicle enters the polygonal area 15 in step S5, the navigation device determines that the vehicle has entered the parking lot and stops the map matching of the vehicle position on the road link (step S6). .
If NO in steps S2 to S5, the process returns to step S1. FIG. 5 is a flowchart showing a map matching method when a vehicle leaves a parking lot. The navigation device, in step S11,
The current position of the vehicle is detected from the information from the GPS receiver 4, and it is checked whether the current position of the vehicle is within the polygonal area 15. If YES in step S11, step S1
If No, the process proceeds to step S15.

In step S12, while the vehicle is traveling in the parking lot (polygonal area 15), the vehicle approaches within a certain range from the exit node 14 of the parking lot (step S12).
12) After that, when turning right or left and accelerating at a certain speed or more, or when traveling a certain distance or more along the road link (steps S13 and S14), step S
15, the navigation device performs map matching of the current position of the vehicle on the road link, assuming that the vehicle has left the parking lot. Note that NO in steps S12 to S14.
In both cases, the process returns to step S11.

In the present embodiment, as described above,
Position information of the entrance and exit of the parking lot is recorded in the CD-ROM 3, and the navigation device uses the time when the vehicle decelerates to a certain speed or less as a trigger to determine whether or not there is a parking lot entrance near the current position of the vehicle. If the vehicle turns right or left near the entrance of the parking lot and enters the polygonal area, it is determined that the vehicle enters the parking lot and the vehicle position is map-matched on the road link. Abort. As a result, in the present embodiment, it is possible to reduce the load on the microcomputer and more accurately determine whether the vehicle has entered the parking lot or has turned the road. Further, the current position of the vehicle can be map-matched on the road link in a short time after the vehicle leaves the parking lot. Further, in the present embodiment, since the parking lot entrance flag is added to the node list so that the node coordinates are also used as the parking lot entrance or exit coordinates, it is possible to prevent an increase in the amount of data. There is also an advantage that you can.

In the above embodiment, the position data of the entrance / exit of the parking lot is shared with the position information of the nodes forming the road link, but the attribute indicating that the parking lot is in the polygonal area. Information may be provided, and the position information (longitude and latitude) of the entrance and exit of the parking lot may be stored in the CD-ROM in association with the information.

[0024]

As described above, according to the present invention,
Position data of the entrance and exit of the parking lot is stored in the map data storage means, and when the speed of the vehicle falls below a certain speed while traveling on the road, the parking lot entrance within the certain range from the current position of the vehicle The presence or absence of the parking lot is checked and it is determined that the vehicle has entered the parking lot when the vehicle turns right or left, so the navigation device does not perform complicated calculations and the vehicle is in the parking lot or on the road. It is possible to accurately determine whether or not the load on the computer can be reduced. As a result, when the vehicle starts traveling again, the display of the current position of the vehicle can be started quickly and accurately, and the reliability is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle-mounted navigation device that realizes a map matching method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a road layer in map data.

FIG. 3 is an explanatory diagram showing a map image represented by road layers.

FIG. 4 is a flowchart showing an operation when a vehicle enters a parking lot in the map matching method according to the embodiment of the present invention.

FIG. 5 is a flowchart showing an operation when a vehicle leaves a parking lot in the map matching method according to the embodiment of the present invention.

FIG. 6 is a schematic diagram showing a map matching method.

FIG. 7 is a schematic diagram showing a method of detecting that a vehicle has entered the parking lot in the conventional map matching method.

[Explanation of symbols]

1 Navigation device body 2 LCD monitor 3 CD-ROM 4 GPS receiver 7 Gyro 8 Vehicle speed pulse detector 9 Operation part 11 simple nodes 12 Intersection node 13 Parking lot entrance node 14 Parking lot exit node 15 Polygonal area 16 Vehicle position mark

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 21/00 G09B 29/10

Claims (4)

(57) [Claims] 1. The road link data and the polygonal area data as well as the parking lot entrance and exit position data are stored in a map data storage means, and the current position of the vehicle is detected by a signal sent from a satellite and detected. The position of the vehicle is displayed on the screen by map matching with the position on the road link, and when the vehicle decelerates below a certain speed, the position data of the parking lot entrance read from the map data storage means is used. Check the presence or absence of a parking lot entrance within a certain range from the present position, and when there is a parking lot entrance within the certain range and the vehicle turns right or left to enter the polygonal area, the road link A map matching method for a vehicle-mounted navigation device, characterized in that upward map matching is stopped. 2. The map matching method for a vehicle-mounted navigation device according to claim 1, wherein the parking lot entrance and exit position data are also used as position data of nodes forming the road link. . 3. The vehicle is said to exit the parking lot when the vehicle approaches the polygonal area, approaches a certain range from the exit, makes a right turn or a left turn, and then accelerates to a certain speed. The map matching method for a vehicle-mounted navigation device according to claim 1, wherein the current position of the vehicle is subjected to map matching on a road link. 4. The vehicle is said to have left the parking lot when the vehicle enters the polygonal area, approaches a certain range from the exit, makes a right turn or a left turn, and then travels a certain distance. The map matching method for a vehicle-mounted navigation device according to claim 1, wherein the current position of the vehicle is subjected to map matching on a road link.