JPH03138517A - Navigation device for traveling body - Google Patents

Abstract

PURPOSE:To prevent the delay of an operation by decreasing the selected and stored number of the positions of a traveling body so that arithmetic operation quantity may be reduced when the speed of the traveling body is high and to enhance accuracy in position detecting by increasing the selected and stored number of the positions when the speed thereof is low by deciding the selected and stored number of the positions of the traveling body on road data in accordance with the speed of the traveling body. CONSTITUTION:A control means 1 detects the traveling distance, the bearing variation and the traveling speed of the traveling body based on output from a bearing sensor 2 and a distance sensor 3 and decides the selected number of the positions of the traveling body on the road data in accordance with the traveling speed of the traveling body. In the case that the speed is high, an operation-enabled time becomes short but the number of previous self positions is reduced by decreasing the selected number, and an arithmetic operation for a present estimated position, a present self position and the probability of existence is performed every previous self position, so that the arithmetic operation time is shortened and the delay of the operation is prevented. In the case that the speed of the traveling body is low, the operation-enabled time becomes long but the accuracy in position detecting is enhanced by increasing the selected number of the positions of the moving body even though the operation time is made longer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a navigation device for a mobile body, such as a car, that displays the current position of the mobile body.

[Conventional technology]

In this type of conventional device, for example,
As shown in Publication No. 112, the estimated position of the moving object obtained from the distance traveled and the amount of change in direction is compared with the road data stored in memory, and the existing road data that is within the range of error is determined. A fixed number of moving object positions on the road data with high probability are stored, and one of the stored moving object positions is selected and displayed.

[Problem to be solved by the invention]

However, in the conventional device described above, the number of moving object positions to be selectively stored is always constant, so when the moving speed of the moving object is fast, a calculation delay occurs in calculating the probability of existence, etc. If the calculation time is slow, there is a problem in that the accuracy of detecting the position of the moving body decreases even though there is sufficient calculation time.

This invention was made to solve the above-mentioned problems, and it is possible to avoid calculation delays even when the moving speed of a moving object is fast, and to improve position accuracy when the moving speed is slow. The purpose of the present invention is to obtain a navigation device for a mobile body that can perform the following tasks.

[Means to solve the problem]

A navigation device for a mobile object according to the present invention includes a means for estimating the position of a mobile object from a travel distance of the mobile object, an amount of change in direction, and a stored mobile object position, and all roads within a certain error range of the estimated position. means for calculating the existence probability and position of a moving object from the data; means for selectively storing the moving object positions in descending order of existence probability in a number corresponding to the moving object speed; A display means for selecting and displaying the information is provided.

[For production]

In this invention, the position of a moving object is estimated from the distance traveled by the moving object, the amount of change in direction, and the stored position of the moving object, and the existence probability and position of the moving object are determined for all road data within a certain error range from this estimated position. is calculated, and the calculated moving object positions are selectively stored in the order of their existence probabilities in a number corresponding to the moving object speed, and one of the selected and stored moving object positions is displayed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows the block configuration of the navigation device for a mobile object according to this embodiment, in which 1 is a control means, 2 is an azimuth sensor that detects the amount of change in the orientation of a mobile object such as a car, and 3 is a sensor that detects the travel distance and speed of the mobile object. 4 is an operation means for setting the initial position of the moving object and commanding the switching of the displayed map, 5 is a map information storage means for storing map information (road data), and 6 is the map information and the position of the moving object. This is a display means for displaying.

Next, the operation of the above configuration will be explained with reference to the flowchart of FIG. In step 10, the position detection operation is started, and in step 11, the direction sensor 2 and the distance sensor 3
From the output, the control means 1 detects the distance traveled, the amount of change in direction, and the moving speed of the moving object. In step 12, the number of selected moving object positions on the road data, which will be described later, is determined in accordance with the moving speed of the moving object. For example, 6 pieces at less than 50 km'/h,
3 pieces for 50 km/h or more and less than 1100 km/h, 100 pieces
For kIII/h or higher, the number of selections is increased at low speeds, such as 2, and the number of selections is decreased at high speeds. In this flow, there are three.

In step 13, the current estimated position of the moving object is calculated from the travel distance, the amount of change in direction, and the previous self-position. Figure 3 shows the case where there were two self-positions last time and three self-positions this time.
43 indicates the previous self-position, C and 2 indicate the current estimated position, Holt indicates the current self-position that was memorized, ri indicates the road data, and C indicates the current self-position that was not memorized. In step 13,
Based on the previous self-position 43 stored in the control means 2, the current estimated position C and C are calculated. In step 14, all the road data stored in the map information storage means 5 are compared with the current estimated positions C and 2, and the current estimated positions C and 2 are compared with each other for the road data that is within a certain error range of the currently estimated positions C and 2. Calculate the existence probability of and the current self-position.

In step 15, the one with the highest probability of existence is selected and memorized among the current self-position hogs, and in step 16, it is determined whether the maximum number, that is, 3, has been reached, and if not, the probability is sequentially increased. Select and memorize in descending order. Therefore, among the four current self-positions Ho to Chi, the current self-position with the lowest probability is not selected and is not stored. Among the currently selected and stored self-positions, only one, for example, the one with the highest probability of existence, is selected and displayed on the display means 6. Among the above-mentioned operations, steps 13 and 14 are performed every 41 previous self-positions.

In the above embodiment, the number of selections of moving object positions on the road data is determined according to the speed of the moving object, and when the speed is high, the calculation time becomes shorter, but by reducing the number of selections, The number of previous self-positions is also reduced, and the current estimated position, current self-position, and existence probability are calculated for each previous self-position, so the calculation time is reduced and no calculation delay occurs. Furthermore, when the moving body is moving at a low speed, the computable time becomes longer, but by increasing the number of selected moving body positions, the accuracy of position detection can be improved even if the computation time becomes longer.

In the above embodiment, when the moving object is moving at high speed, the number of selected moving object positions on the road data is reduced in order to prevent calculation delays; however, at high speed, the vehicle actually turns only in a narrow angular range in front. Therefore, there is no particular problem. Further, in the above embodiment, a maximum of three items are stored, but if there are only two items whose existence probability is higher than a certain threshold value, only those two items may be stored.

〔Effect of the invention〕

According to the present invention, the number of selected memorized locations of moving object positions on road data is determined according to the speed of the moving object, and at high speeds, the amount of calculation is reduced by reducing the number of selected memorized locations. Calculation delays can be prevented, and at low speeds, the number of selections stored can be increased to improve position detection accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the apparatus of the present invention, FIG. 2 is a flowchart showing the operation of the apparatus of the invention, and FIG. 3 is a diagram showing road data and each position of a moving object by the apparatus of the invention. ■... Control means, 2... Orientation sensor, 3... Distance sensor, 4... Operating means, 5... Map information storage means, 6... Display means.

Claims (1)

[Claims] A distance speed sensor that detects the travel distance and speed of the moving object, an azimuth sensor that detects the amount of change in the direction of the moving object, and a means for estimating the position of the moving object from the output of each of the sensors and the stored moving object position. , a road data storage means for storing road data; a means for calculating the existence probability of a moving object and a position on the road data for road data within a certain error range from the estimated position; What is claimed is: 1. A navigation device for a moving body, comprising means for selectively storing a number of positions corresponding to the speed of a moving body; and display means for selecting and displaying only one of the selectively stored positions of the moving body.