JP2000146607A - Navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make obtainable more accurate traveling position of an automobile even if the branch angle of road is shallow and parallel state continues by performing matching correction where matching operation is executed based on a traveling state evaluation value and traffic information data. SOLUTION: In independent navigation processing, it is judged whether a map matching candidate road is branched shallowly and parallel state continues or not and if the answer is YES, traffic jam information on each parallel road link is fetched from an FM multiplex receiving and processing section 19. Furthermore, it is judged whether one road link is jammed and the other road link is not jammed, and current traveling state is checked if only one road link is jammed. When it can be judged from the traveling state that a vehicle is traveling sufficiently in line with the traffic flow, the unjammed road link is map-matched preferentially otherwise the road link determined to be jammed based on the traffic information is map-matched preferentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device, and more simply, a direction sensor, a distance sensor, and a GPS (Global Posisioning System) mounted on a vehicle.
A vehicle presence probability region (refers to a region where the vehicle presence probability is determined by the accuracy of the vehicle estimation method and using a vehicle absolute position detection sensor or the like that uses a vehicle or the like) and a vehicle presence probability is equal to or more than a certain value.
EP "), and matching the estimated position with road network data obtained from a road map memory to determine the position of the vehicle.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to obtain a traveling locus of a vehicle using an azimuth sensor and a distance sensor. This method is called dead reckoning because it detects its own position only with a sensor mounted on the vehicle, and can be adopted relatively easily because no external support equipment is introduced.

However, according to this dead reckoning navigation, an error occurs in the sensor, and the position detection error accumulates as the traveling distance increases.

Therefore, a road matching method has been proposed which eliminates the accumulated error by performing pattern matching between the traveling locus obtained by the above-mentioned sensor and the road network data, and a navigation device utilizing this has been developed. Further, in the above navigation device, if the road network data is inaccurate or the path network is complicated or lattice-shaped, it is difficult to compensate for a position error obtained by dead reckoning with a map, May be difficult to detect. Therefore, once the vehicle position is incorrect, it may not be possible to recover the vehicle to an accurate position.

Further, when the similarity and the CEP in each of the passages of the vehicle are evaluated during the road matching navigation, for example, if the similarity is low in any of the passages and the road cannot be identified, the passage is identified. If it is possible, but the probability of being on another road cannot be neglected, the absolute position of the vehicle can be determined using GPS (Global Posisioning System), depending on the situation, such as when a single road can be determined with considerable possibility. A technology is being developed that determines the estimated position of a vehicle from a known wireless navigation system and corrects the vehicle position obtained by road matching navigation using the estimated position, thereby determining a vehicle position with a higher probability. .

[0006]

However, the conventional navigation device described above has the following problems. That is, as shown in FIGS. 5A and 5B, the branch angle of the road is shallow, and map matching is temporarily performed on an incorrect road due to an error in sensor information such as vehicle speed and gyro.
Further, as shown in FIG. 6, when roads continue running side by side in the CEP, there is a problem that the own vehicle position continues to be map-matched on an incorrect road.

It is an object of the present invention to provide a navigation device which can obtain a more accurate traveling position of a vehicle even when a road branch angle is shallow and parallel running continues.

[0008]

According to one aspect of the present invention, there is provided a vehicle position detecting section for detecting a position of a vehicle, and a running state detecting section for detecting a running state related to a running speed of the vehicle. A road data storage unit that stores road data, a traffic information data receiving unit that receives traffic information data about each road, and a traveling state evaluation unit that obtains a traveling state evaluation value of the vehicle based on the traveling state detection unit. A map matching means for obtaining an area having a high probability that a vehicle is present based on the detected vehicle position and the road data and matching the vehicle position on the road, and specifying the current position on one road by the map matching means A similarity candidate determination unit that determines whether there is another matching candidate road with a high degree of similarity in the region where the probability is high,
In the case where the similar candidate exists, a matching correction unit that executes a matching operation of a map matching unit based on the traveling state evaluation value and the traffic information data is provided.

According to the first aspect of the present invention having the above configuration, the following operation can be obtained. That is, based on the traveling state evaluation value and the traffic information data, it is possible to evaluate which one of the roads the vehicle is currently traveling on, and map matching can be performed even if the own vehicle has a shallow road branching angle and is approaching a parallel running road. By correcting the matching operation of the means, it is possible to obtain the traveling position with high accuracy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a navigation device according to the present invention will be described below with reference to the drawings. Each function of the embodiment described below is realized by a predetermined mechanism or software controlling a computer and a peripheral device. The invention and the embodiments have been described assuming virtual circuit blocks such as ". Therefore, for each block, each hardware element or software element that realizes this does not correspond one-to-one.

[1. Configuration] FIG. 1 is a block diagram showing a configuration of a vehicle-mounted navigation device according to a first embodiment of the present invention. In this figure, reference numeral 1 denotes an absolute position and direction detection unit, for example, a GPS (Global Positioning System).
m) It is constituted by a receiver, and detects the latitude / longitude of the current position of the own vehicle, that is, position data and azimuth based on a signal received by the antenna. Reference numeral 2 denotes a relative azimuth detecting unit which detects a change in azimuth accompanying the traveling of the own vehicle, and is constituted by, for example, a geomagnetic sensor or a gyro. 3 is a vehicle speed detection unit,
It detects the speed of the own vehicle.

A display unit 10 has a display screen such as a CRT or a liquid crystal display, and displays an initial setting menu, a road map, a mark indicating the position of the vehicle, a recommended route, and the like on the display screen. I do. Reference numeral 11 denotes an input unit, which is composed of a keyed boat or the like, or a display unit 1
0 as a touch panel provided on the display screen. The input unit 11 allows the driver to set a destination and parameters required for route calculation (hereinafter, referred to as route mode) at the time of initial setting. Reference numeral 9 denotes a user interface unit that connects the CPU 4 described below, the display unit 10, and the operation unit 11.

Reference numeral 12 denotes a CD-ROM, which stores map data including various road information such as intersection position data.
Specifically, this map data is obtained by dividing a Japan road map into a mesh shape, and includes road data composed of a combination of nodes and links for each mesh unit, and background data of buildings and the like. Here, a node is a point that divides a road into a number of sections, and a route connecting the nodes is a link.
A CD-ROM controller 13 reads map data from the CD-ROM 12.

Reference numeral 15 denotes a main CPU 20 described later at the time of startup.
It is a ROM that is accessed more, and also stores a program for route calculation and the like. Reference numeral 16 denotes a dynamic RAM (DRAM) for loading a main program. 1
Reference numeral 7 denotes a non-volatile memory, which is configured by, for example, backing up an SRAM with a battery or the like. The non-volatile memory 17 is backed up by a battery or the like even when the power is turned off, and stores and holds the device setting state immediately before the power is turned off. Reference numeral 18 denotes a VideoR provided for the display unit 10
AM (VRAM). Reference numeral 19 denotes an FM multiplex broadcast receiving and processing unit for extracting desired data from FM broadcast waves.

Reference numeral 20 denotes a main CPU, which includes a map matching processing section 21, a similar candidate determination section 22, and a matching correction section 23.
Etc. are provided.

The map matching processing section 21 includes an estimated position estimated from azimuth data and speed data detected by the relative azimuth detecting section 2 and the vehicle speed detecting section 3, and a positioning position detected by the absolute position detecting section 1. While matching the current position of the vehicle to be displayed on the display screen with the road on the map.

When specifying the current position on one road by map matching by the map matching processing unit 21, the similar candidate determination unit 22 includes other matching candidate roads having a high degree of similarity in a high probability area. Is determined. Based on the result of the determination by the similarity candidate determination unit 22, the matching correction unit 23 determines that the vehicle speed detection unit 3
The matching operation of the map matching means is corrected based on the traveling state evaluation value obtained from the data and the traffic information data obtained from the FM multiplex receiving unit 19.

[2. Operation and effect] The operation of the present embodiment configured as described above will be described with reference to the flowcharts shown in FIGS. 2 and 4 and the transition of the stop state in FIG.

(1) Evaluation of Running State of Vehicle FIG. 2 is a flowchart for evaluating the running state of the vehicle. FIG. 3 shows the transition of the traveling state.

First, it is determined whether or not the vehicle has stopped in ST1. If the vehicle is running, the current running state of the vehicle is obtained as parameters such as the maximum speed and average speed for evaluating the running state in ST2. I do.

If the car is stopped in ST1, S
At T3, it is determined whether or not the vehicle has moved after the previous stop determination, and if it has moved, the parameters acquired during running are evaluated at ST2. That is, the parameters acquired in ST2 are stored in ST4.
If the parameter exceeds a certain reference value, ST
At 5, the running state is shifted in the direction of "flow" in FIG. (For example,
(If the current state is Si, move to Si-1.)
In ST6, the traveling state is moved in the direction of "congestion" in FIG. 3 (for example, if the current state is Si, the state is moved to Si + 1). Thereafter, in ST7, the parameters for the traveling state evaluation are initialized.

Therefore, when the vehicle travels along a traffic flow and stops repeatedly at a traffic light or the like, the traveling state is evaluated so as to be biased toward the "flow" shown in FIG. Is evaluated so as to be biased toward "congestion" in FIG.

(2) Correction of Map Matching Next, a process for performing a map matching to a road with a higher probability using the above-mentioned running state will be described with reference to a flowchart of FIG.

First, normal self-contained navigation processing is performed in ST8. This processing is performed by the relative azimuth detecting unit 2 and the vehicle speed detecting unit 3 shown in FIG.
Calculates the approximate position by integrating the azimuth and distance displacement based on the data obtained from, or comparing the absolute position and the positioning position of the azimuth detecting unit 1 etc. Perform the processing up to

In the self-contained navigation processing in ST1, it is determined whether or not the map matching candidate road branches shallowly and continues running in parallel.
If it is determined at T9 that the map matching candidate road branches off shallowly and it is determined that parallel running will continue, the traffic congestion information of each of the parallel road links is acquired from the FM multiplex reception and processing unit 19 at ST10.

After the congestion information is obtained in ST10,
In ST11, it is determined whether one road link is congested and the other road link is not congested. If only one is congested, the current traveling set in FIG. Check the status. If it can be determined that the vehicle is traveling along the traffic flow from the traveling state,
At T13, the road links that are not congested are preferentially map-matched. Otherwise, if it is determined by ST14 that the vehicle is running slowly due to congestion, the traffic links at ST15 are given priority over the congested road links. Map matching.

Incidentally, in ST9, when the candidate road diverges shallowly and parallel running does not continue, in ST11, it cannot be determined that one road link is congested and the other road link is congested, or in ST13 and ST14. If the traveling state is an intermediate state that cannot be said to be either, a normal map matching process is performed in ST20.

[3. Other Embodiments] The present invention is not limited to the above-described embodiments, but also includes the following other embodiments. That is, the map matching process is not limited to the above-described process, and may be a conventional GPS system or a self-sustained traveling system alone or a system called D-GPS (Differential GPS).

[0029]

As described above, according to the present invention,
Even when the road branch angle is shallow and the vehicle continues to run side by side, it is possible to provide the user with an accurate vehicle traveling position.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a navigation device according to an embodiment of the present invention.

FIG. 2 is a flowchart for evaluating a traveling state in the embodiment.

FIG. 3 is a diagram showing transition of a traveling state in the embodiment.

FIG. 4 is a flowchart showing correction of map matching in the embodiment.

FIG. 5A is a diagram for explaining a first example in which a road branch angle is shallow and incorrect map matching is caused by parallel running of the road.

FIG. 5B is a diagram for explaining a second example in which a road branch angle is shallow and incorrect map matching is caused by parallel running of the road.

FIG. 6 is a diagram for explaining a third example in which a road branch angle is shallow and incorrect map matching is caused by parallel running of the road.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Absolute position and direction detection part 2 ... Relative direction detection part 3 ... Vehicle speed detection part 4 ... Main CPU 10 ... Display part 11 ... Input part 19 ... FM multiplex reception and processing part 13 ... CD-ROM control part 21 ... Map matching Processing unit 22: Similar candidate determination unit 23: Matching correction unit

Claims (2)

[Claims] 1. A vehicle position detecting section for detecting a position of a vehicle, a running state detecting section for detecting a running state related to a running speed of the vehicle, a road data storing section for storing road data, and traffic information data for each road. Traffic information data receiving means for receiving, a traveling state evaluation means for obtaining a traveling state evaluation value of the vehicle based on the traveling state detection unit, and a probability that a vehicle is present based on the detected vehicle position and road data. A map matching means for finding a high area and matching the vehicle position on the road; and when the current position is specified on one road by the map matching means, a road of a matching candidate having a high similarity to the area having a high probability is determined by the other. A similar candidate determining means for determining whether or not there is also a similar candidate, and, if the similar candidate exists, a similar candidate determining means based on the traveling state evaluation value and the traffic information data. Navigation apparatus characterized by comprising a matching modifying means, the executing the matching operation of the flop matching means. 2. The method according to claim 1, wherein the matching correction means determines whether or not each candidate road has a difference in the degree of congestion based on the received traffic information data. 2. A navigation device according to claim 1, further comprising: priority matching means for preferentially performing map matching on one of the roads.