JPH0383088A - Vehicle mounted navigation device - Google Patents

Abstract

PURPOSE:To achieve simple processing and to reduce data by dividing the bearing of a vehicle by a value, which is obtained through integration by a travel distance, by the integral value of the travel distance and correcting the position and bearing of the vehicle with this value as the average advancing bearing of the vehicle in some section. CONSTITUTION:A signal outputted from a speed sensor 5 for indicating the travel distance of the vehicle and a signal outputted from an angular velocity sensor 6 for indicating the travel bearing of the vehicle are cumulatively added by an estimated position calculating means 7 and an estimated bearing calculating means 8, and the estimated current position and bearing of the vehicle are calculated. Since these estimated position and bearing include cumulative errors, an average advancing bearing calculating means 9 divides the value, which is obtained by integrating the estimated bearing of the vehicle by the travel distance, by the integral value of the travel distance and takes it as the average advancing bearing of the vehicle in some section. After that, a position/bearing correcting means 11 compares the value with map data 10, and corrects the position and bearing of the actual vehicle. Thus, a bearing suitable for comparing with map data can be calculated by simple arithmetic function.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an in-vehicle navigation device that displays the position and direction of a vehicle, map information of its surroundings, and the like.

BACKGROUND OF THE INVENTION FIG. 3 shows an example of the configuration of a conventional in-vehicle navigation device. In FIG. 3, 31 is a sensor section, 32
33 is an auxiliary storage device, and 34 is a display device. The sensor section 31 includes a speed sensor 35 that detects the travel distance of the vehicle, and an angular velocity sensor 36 that detects the travel direction of the vehicle. The position/orientation correction device 32 is
means 37 for receiving the signal from the speed sensor 35 and calculating the current estimated position of the vehicle; means 38 for receiving the signal from the angular velocity sensor 36 and calculating the current estimated heading of the vehicle;
A position/orientation correction means 40 that corrects the cumulative error of the calculated estimated position and estimated orientation using the map data 39 of the auxiliary storage device 33, and a map that displays the corrected position and orientation on a display device 34 such as a CRT. It is provided with display means 41 for displaying on the top.

In such conventional devices, the position and orientation are corrected by the fourth
This was carried out using the schematic diagram shown in the figure and the algorithm shown in FIG. That is, the travel distance 42 is determined from the speed sensor 35, and the change angle 4 is determined from the angular velocity sensor 36.
5 (step 51), the travel distance 42 obtained from the speed sensor 35 is added to the previous position 43 to obtain the estimated position 44, and the change angle 45 obtained from the angular velocity sensor 36 is added to the previous direction 46 to obtain the estimated direction. 47 is determined (step 52), and compared with the map data 39 to determine a corrected position 48 and corrected orientation 49, which are then matched on the map on the display device 34 (step 53).

FIG. 6 shows an example of an algorithm for selecting candidate roads on which a vehicle is likely to exist from the map data and correcting the estimated position and orientation during this matching. Here, first, in step 61), roads with a positional error within a certain value are retained from the map data, then roads with an orientation error within a certain value are retained and selected as candidate roads in step 62), and then this road is the only one. If this road is the only one, it is assumed that the vehicle is on this road and the position closest to the estimated position is set as the vehicle's current position (step 64), and the direction of this road is determined as the vehicle's current position. The current direction is set (step 65). On the other hand, if this road is not unique, it is considered that the position and orientation cannot be determined, and the calculated estimated position and orientation are maintained as they are without modification.

Problems to be Solved by the Invention However, in the above conventional vehicle position and orientation correction method,
For example, when changing the direction of travel to avoid an obstacle 71 on the road as shown in FIG. 7, or changing the direction of travel to change lanes on a road with multiple lanes on one side as shown in FIG. In this case, if an attempt is made to make a correction using the changed orientation 72.81, there is a risk that a candidate road may not be selected or that a clearly inappropriate road may be selected by mistake.

As a measure to prevent this, a vector 93 connecting the previous position 91 and the current position 92 is created as shown in FIG.
A method of using the direction 94 of this vector 93 as the direction for comparison with map data has also been considered. Although this method has a relatively simple algorithm and has the advantage of being resistant to minute azimuth fluctuations compared to the previous method, it requires inverse trigonometric functions or a huge data conversion table to replace it in order to calculate the azimuth. There is a problem in that this is difficult to achieve in navigation devices where simple processing and data reduction are desired for practical use.

The present invention solves these conventional problems and uses a simple calculation function to display maps using simple calculation functions, even if the heading changes slightly due to avoiding obstacles or changing lanes. An object of the present invention is to provide an excellent in-vehicle navigator device capable of correcting the position and direction of a vehicle by calculating a direction suitable for comparison with data.

Means for Solving the Problems In order to achieve the above object, the present invention divides the value obtained by integrating the estimated heading of the vehicle by the distance traveled, based on the following calculation formula, and calculates this by a certain value. This information is used to correct the position and direction of the vehicle as the average direction of travel of the vehicle in the section.

d]: Minute travel distance θ: Estimated vehicle orientation θ° expressed as a function of dl
Effect on vehicle's average traveling direction Therefore, according to the present invention, even if the vehicle's direction changes slightly due to avoiding obstacles or changing lanes, it will not be significantly affected by the direction, and map data can be calculated using a simple calculation function. This has the effect of being able to calculate a direction suitable for comparison with

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, 1 is a sensor section, 2 is a position/direction correction device,
3 is an auxiliary storage device, and 4 is a display device. The sensor unit 1 includes a speed sensor 5 that detects the travel distance of the vehicle, and an angular velocity sensor 6 that detects the travel direction of the vehicle. The position/direction correction device 2 includes a means 7 for receiving a signal from the speed sensor 5 and calculating the current estimated position of the vehicle, and a means 8 for receiving a signal from the angular velocity sensor 6 and calculating the current estimated position of the vehicle. , a means 9 for calculating an average heading in response to a signal from the calculating means 7.8, and a means 9 for calculating the average heading, using the map data 10 in the auxiliary storage device 3 to calculate the cumulative error included in the calculated estimated position and average heading. Position and orientation correction means 11 to be corrected
and display means 12 for displaying the corrected position and orientation on a map displayed on a display device 4 such as a CRT.

Next, the operation of the above embodiment will be explained. First, a signal representing the traveling distance of the vehicle outputted from the speed sensor 5 and a signal representing the traveling direction of the vehicle outputted from the angular velocity sensor 6 are cumulatively added by calculation means 7 and 8, respectively, to obtain the current estimated position of the vehicle. and the estimated direction is calculated. Since these estimated positions and estimated directions include accumulated errors, the average heading calculating means 9 averages temporary changes in the heading, and then the position/direction correcting means 11 compares them with the map data 10. The actual vehicle position and orientation are compared and corrected to match the location and orientation on the map. The corrected position and orientation are then displayed on the map of the display device 4 by the display means 12. The average heading θ゛ is calculated based on the idea that ``vehicle heading that does not include mileage is not reflected in the average heading θ゛.''
It is calculated using the following formula.

fd [ dl, estimated vehicle orientation θ° expressed as a function of minute travel distance θ + dl
Average Traveling Direction of the Vehicle Next, the position and orientation correction operation using this average traveling direction θ' will be explained with reference to FIG. First, in step 21, the cumulative azimuth distance product TI (L, which represents the product of estimated azimuth and traveling distance) and the cumulative traveling distance 1 are cleared.Next, in step 22, the traveling distance di and the change angle dθ are determined from the sensor data, and in step 23 In step 24, the cumulative traveling distance l and the estimated heading θ are calculated.
is calculated, and the position and direction are corrected by comparing it with the map data using the average heading θ゛ in step 25. Then, in step 26, it is determined whether the matching is successful or not, and if the matching is successful, the process jumps to step 21 and the cumulative azimuth distance product TII is determined.
Clear L and cumulative mileage l, and if matching is not completed, jump to step 22 and repeat this routine.

Effects of the Invention As is clear from the above embodiments, even if the direction of travel changes slightly due to avoiding obstacles or changing lanes, the user may be dragged along by the direction and choose the wrong road, or the road The present invention has the effect that it can be compactly assembled as an in-vehicle device because it does not become impossible to select, and can calculate a direction suitable for comparison with map data using a simple calculation function.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an in-vehicle navigation device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the correction operation of the device, and FIG. 3 is an example of a conventional in-vehicle navigation device. FIG. 4 is a schematic diagram for determining the estimated position and orientation in the conventional example, FIG. 5 is a flowchart for correcting the position and orientation in the conventional example, and FIG. 6 is a schematic diagram for determining the position and orientation in the conventional example. A flowchart for matching the direction to a map, FIGS. 7 and 8 are schematic diagrams for explaining problems in the conventional example, and FIG. 9 is a schematic diagram for explaining another method for determining the heading in the conventional example. It is a schematic diagram. 1...Sensor part, 2...Position and orientation correction device, 3...
- Auxiliary storage device, 4... Display device, 5... Speed sensor, 6... Angular velocity sensor, 7... Estimated position calculation means, 8... Estimated direction calculation means, 9... Average progress Azimuth calculation means, 10...Map data, 11...Position/azimuth correction means, 12...Display means.

Claims (1)

[Claims] A means for detecting the traveling distance of the vehicle, a means for detecting the traveling direction of the vehicle, a means for calculating the position and direction of the vehicle from the detected traveling distance and the traveling direction, and a means for integrating the direction of the vehicle by the traveling distance. means for dividing the value by the integral value of the traveling distance and calculating this as the average traveling direction of the vehicle in a certain section; and means for correcting the cumulative error of the calculation result using map data;
An in-vehicle navigation device comprising means for displaying the corrected vehicle position and orientation on a map of a display device.