JPS62140017A - Present position recognition apparatus for vehicle - Google Patents

Abstract

PURPOSE:To always enable the recognition of the present position with good accuracy, by mounting a present position recognizing means by an earth magnetic sensor and a present place confirming means by GPS. CONSTITUTION:A present position recognizing means (b) is constituted of an earth magnetic sensor 5 and a running distance measuring device 6 and the sensor 5 outputs a signal showing the azimuth of the present position and the measuring device 6 outputs a signal showing a running distance measured thereby to the control circuit 1. A present position recognizing means (d) is constituted of GPS7 to receive signals from a plurality of GPS satellites and directly calculates the coordinates of the present position to output the signal showing the coordinates to the circuit 1. A predetermined formulas for calculating distance correction and drift angle correction and others are stored in a memory circuit 3. By this method, the present position is recognized in a usual state by the means (b). At this time, a distance correction constant and a drift angle correction constant calculated according to the predetermined formula stored in the circuit 3 are used. Next, when a GPS receiving state is good, the circuit 1 changes over from the means (b) to the means (d) to perform the recognition of the present position. When the GPS receiving state becomes unsatisfactory, the means (d) is returned to the means (b) to recognize the present position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a current location recognition device for a vehicle, and more particularly to a current location recognition device for a vehicle equipped with a geomagnetic sensor.

(Prior Art) The vehicle current location recognition device as described above is usually used in a vehicle travel guidance device as described in, for example, Japanese Patent Application Laid-Open No. 5716112 and Japanese Patent Application Laid-Open No. 57-206819. However, since this current location recognition device uses a geomagnetic sensor (11u) as described above, it is necessary to perform angle correction. As a method for correcting this declination, for example, as described in Japanese Unexamined Patent Publication No. 128812/1983, there is a known correction method in which the Franks gate geomagnetic sensor is mounted on a vehicle by tilting the declination bone. However, in this correction method, once the geomagnetic sensor is installed, its orientation cannot be changed, which causes a large error when the vehicle moves to a location with a different declination angle.

(Objective of the Invention) Therefore, an object of the present invention is to provide a current location recognition device for a vehicle that is capable of accurately correcting a geomagnetic sensor, and is capable of always accurately determining the current location. .

(Structure of the Invention) As shown in FIG. 1, the current location recognition device for a vehicle according to the present invention includes first current location recognition means using a geomagnetic sensor a, G.
A second current location recognition means d by the PSc, and usually a first
The current location recognition means recognizes the current location, and when the GPS reception condition is good, the second current location recognition means recognizes the current location, and at this time, the control means e is provided for correcting the orientation of the geomagnetic sensor. This is a characteristic feature.

(Effects of the Invention) As described above, the vehicle current location recognition device of the present invention includes a first current location recognition means using a geomagnetic sensor, and a second current location recognition means using a GPS.
Since it is equipped with a current location recognition means, the declination of the geomagnetic sensor can be corrected by the first current location recognition means, and on the other hand, uneven reception of GPS can be corrected by the first current location recognition means, so that accuracy can always be maintained. Good current location recognition can be performed.

(Embodiment) Hereinafter, a current location recognition device for a vehicle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First, the principle of the present invention will be explained with reference to FIG.

First point A, which is the first point with good GPS reception
Let the coordinates of be (Xo, yo). The quality of this GPS reception is determined by the GDOP value.

Assume that the vehicle departs from this first point A, passes through second and third points B and C where GPS reception is poor, and reaches a fourth point. The first coordinates recognized by the geomagnetic sensor and the distance sensor at this fourth point are (Xl, yl), and the second coordinates recognized by the GPS at the fourth point are (Xl, yl).
Suppose that (represented by the symbol D') is (X2, y2).

The above is the straight line distance between points A and B. , point Δ−B′
The straight line distance between and the azimuth angle θ of destination B. , recognition destination B
The azimuth angle θ of ' is expressed by the following formulas.

death. = 8, '(x+-xo)' + (y+-
yo)2 (t)'l+5'.

V2'Ja When the distance correction constant R is determined from the above formula, the following equation is obtained, and when the declination correction constant Δθ is obtained, Δθ=θ−00(6). Therefore, if correction is made with this R and △θ,
You can always recognize the correct current location.

FIG. 3 is a circuit diagram showing a current location recognition device according to an embodiment of the present invention.

In FIG. 3, reference numeral 1 indicates a control circuit constituted by a microcomputer, and this control circuit 1 includes an arithmetic circuit 2 and a storage circuit 3 connected thereto. This arithmetic circuit 2 includes a first current location recognition means composed of a geomagnetic sensor 5 and a mileage measuring device 6 via a human output interface 4, and a second current location 8 composed of a GPS 7. ? A second identification means d is connected. The geomagnetic sensor 5 is a fluxgate geomagnetic sensor that outputs a signal representing the direction of the current location to the control circuit l.

The mileage measuring device 6 measures the distance traveled from the starting point to the current location based on the number of rotations of the tires, etc., and outputs a signal indicating the distance traveled to the control circuit 1.

Further, the above-mentioned formulas (1) to (4), etc. are stored in the above-mentioned storage circuit 3.

The GPS 7 receives signals from multiple GPS satellites,
The coordinates of that point are directly determined and a signal indicating these coordinates is output to the control circuit 1. The current location and travel trajectory of the vehicle that have been recognized as described above are displayed on a display 8 connected to the ;lii control circuit 1 via the human output interface 4. This display 8 is composed of a CRT or the like.

Next, the operation of the vehicle current location recognition device of the present invention will be explained with reference to FIG. It is assumed that in the normal state, the first current location recognition means including the geomagnetic sensor 5 and the mileage measuring device 6 is used to determine the current location.

First, it is determined whether or not GPS is being received, and if the determination is NO, the control is immediately terminated, and if the determination is YES, the GDOP value is calculated. Next, it is determined whether or not this GDOP value is 2 or less, and if this determination is NO, the control is immediately terminated, and if YES, it is determined whether GPS reception is being performed for the first time.

When this determination is YES, the coordinates (XO, yo) received by the second current location recognition means d are set as the departure location coordinates, and the control process is completed. If this is not the first time GPS reception has been received, the coordinates (X+, y+
) as the arrival location coordinates, and the coordinates determined by the second current location recognition means d, that is, cps5:3: coordinates (x2, y2)
shall be. Next, the above equations (1) and (2) are calculated, and based on these, the distance correction constant R is calculated from equation (5). Further, the above equations (3) and (4) are calculated, and based on these, the argument correction constant is determined from equation (6).

These correction constants R and Δθ are as described in 1. It is stored in the α circuit 3. After this, receive coordinates of destination (x2, yz)
Let be the new starting point coordinates (xo, yo), and 1
Complete the routine.

The correction constants R and Δθ are used as correction constants when the first current location recognition means recognizes the current location. Further, when the GPS reception condition is good, the control circuit 1
The first current location recognition means is switched to the second current location recognition means d to perform current location recognition, and then when the GPS reception condition becomes poor, the system is switched back to the first current location recognition means.

As described above, according to the current location recognition device of the present invention, it is possible to always perform good current location recognition.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the vehicle current location recognition device of the present invention, FIG. 2 is an explanatory diagram illustrating the principle of declination correction, etc. of the vehicle current location recognition device of the present invention, and FIG. 3 is the present invention. On-site inspection 31' for vehicles according to an embodiment of the invention
FIG. 4 is a flowchart for explaining the operation of the control circuit. a... Geomagnetic sensor, b... First current topography 11 means, C... GPS, d...
Second current location recognition means, e... control circuit.

Claims (1)

[Claims] A first current location recognition means using a geomagnetic sensor, a second current location recognition means using GPS, and usually the first current location recognition means perform current location recognition, and when the GPS reception condition is good, current location recognition is performed using the second current location recognition means. The current location recognition device for a vehicle also includes a control means for correcting the orientation of the geomagnetic sensor at this time.