JPS6266114A - Corretion circuit for directional data - Google Patents

Abstract

PURPOSE:To correct an error of a direction detector automatically while traveling by providing a means to correct directional data based on the directional information at the time of passing through a specific point of a network of roads to the output sides of a direction arithmetic part and a map storage part. CONSTITUTION:A difference detection part 4 compares the information on the network of roads inputted from the map storage part 2 for every prescribed distance travel by a distance sensor 1 with the actual directional data inputted from the direction arithmetic part 7 and operates the difference and an average arithmetic part 5 averages the difference value. A bias level at the specific point C1 is denoted as Xo-Yo and if the direction at the specific point C2 is made theta1' although it is to be theta1 properly, the arithmetic part 5 operates it to correct to X'o-Y'o approximately. In this way, the error of the direction detector can be corrected automatically in an ordinary traveling state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in route guidance devices for vehicles, and more particularly to techniques for correcting azimuth data at specific points on a road network.

2. Description of the Related Art Recently, with the development of advanced information technology, technologies for displaying various information on vehicles such as automobiles are being developed. One such information display device is a so-called route guidance device that displays useful information such as the current location and direction of a self-propelled vehicle so that the driver can safely drive in unfamiliar areas.

In order for this route guidance device to provide all accurate information to the driver, accurate detection of direction is essential. In particular, azimuth detection devices that detect azimuth by detecting geomagnetism often obtain inaccurate azimuth data due to the influence of disturbance magnetic fields, and correction is essential.

The technique disclosed in Japanese Unexamined Patent Publication No. 58-135911 relates to a device for correcting errors in the above-described direction detecting device. As shown in FIG. 5, the correction device according to the conventional technology displays the omnidirectional detection pattern q actually output by the azimuth sensor when the vehicle is turned 360 degrees and the reference pattern r in the non-magnetized state of the vehicle on a display screen S. It was displayed above and manually adjusted by operating the volume so that the omnidirectional detection pattern q falls within the area of the reference pattern r.

Note that the symbol t in FIG. 5 indicates the X and Y coordinate axes.

Problems to be Solved by the Present Invention As described above, according to the conventional technology, in order to correct the error of the direction detection device, the vehicle must first be rotated 360 degrees to obtain omnidirectional data, and then displayed. Adjustments had to be made manually while looking at the screen. That is, 360
In order to perform multiple rotations, it is necessary to select a location that has a certain amount of space, such as a plaza or parking lot, and does not interfere with traffic, but this is preferred in cities where there is little surplus space. It was difficult to choose a suitable location. In addition, having the occupant make manual adjustments while looking at the display screen places a corresponding burden on the occupant, and some occupants may find it extremely difficult to make such adjustments while driving the vehicle.
In some cases, it was not possible to make appropriate corrections. Furthermore, according to the conventional technology, correcting errors always requires driving and operation, making it very difficult to perform corrections frequently.

Therefore, when traveling long distances, incorrect route guidance may be performed due to the superposition of errors.

Means for Solving the Problems The present invention was devised to solve the above-mentioned problems.In order to automatically correct the error of the direction detection device while driving,
It is an object of the present invention to provide an azimuth data correction circuit in which a route guidance device is equipped with a means for correcting azimuth data from an azimuth detection unit based on azimuth information of a specific point obtained from a map storage unit when passing through a specific point on a road network. It is something.

Operation The operation of the azimuth data correction circuit according to the configuration of the present invention will be explained.

The map storage unit stores information on a specific position on the road network and azimuth information regarding the magnetic north direction or latitude and longitude of the road network at that specific point, and when passing through the specific point, the azimuth information and the azimuth detection unit are stored. The detected orientation data is corrected by comparing the actual orientation data obtained from the data.

First Embodiment A preferred first embodiment of the present invention will be described with reference to FIG.

In the first embodiment, azimuth data is corrected based on the average value of the difference between azimuth information stored every time a vehicle travels a predetermined distance and actually measured azimuth data, and its configuration will be explained.

In FIG. 1, 1 is a distance sensor, 2 is a map storage unit, and 3 is a distance sensor.
is a path calculation unit, 4 is a difference detection unit, 5 is an average value calculation unit, 6
(- is a geomagnetic sensor, 7 is an azimuth calculation section, 8 is a bias variable section, and 9 is a display section.

Next, each configuration will be explained in detail. The distance sensor 1 is, for example, a sensor that generates one pulse signal every rotation of the tire, and is connected to the map storage section 2 .

The map storage unit 2 stores road network data, and the route calculation unit 3
The road network data is transmitted to the route calculation unit 3 in response to access from the route calculation unit 3.

The road network data is, for example, a value obtained by converting the digit 1δ of an intersection or road bend on the map coordinates into a coordinate value. It stores direction information at a point. This azimuth information is stored, for example, together with an identification flag to distinguish it from the road network data, and is output to the difference detection section 4 every time the vehicle travels a predetermined distance in accordance with the distance signal from the distance sensor 1.

The route calculation unit 3 calculates a route based on road network data input from the map storage unit 2 and azimuth data from the azimuth calculation unit 7.

The difference detection section 4 has each input section connected to the map storage section 2 and the azimuth calculation section 7, and the output section connected to the average value calculation section 5 at the subsequent stage. This difference detection section 4Vi calculates the difference between the direction information signal from the map storage section 2 and the direction data from the direction calculation section 7, and inputs the difference value to the average value calculation g45.

The average value calculation section 5 accumulates the difference values inputted from the above-mentioned difference detection 81S4 a predetermined number of times, calculates an average value, and derives a signal to the subsequent bias variable section 8 based on this average value. .

The geomagnetic sensor 6 takes the magnetic field applied in the left-right direction of the vehicle as an X component, and the magnetic field applied in the front-rear direction as a Y component, converts the X component and the Y component into electrical signals, and inputs the electric signals to the azimuth calculating section 7.

The azimuth calculation section 7 processes the signal input from the geomagnetic sensor 6, calculates an azimuth vector that is a combination of the X component and the Y component, converts it into a binary signal, and supplies the signal to the subsequent difference detection section 4 and bias variable section. 8 to derive the binarized signal.

The bias variable section 8 adds or subtracts a correction value to the binary signal inputted from the azimuth calculation section 7, and this correction value is varied based on the signal from the average value calculation section 5. . Note that the map storage section 2 and route calculation section 3
It goes without saying that the other difference detecting section 4, average value calculating section 5, bias variable section 8, direction calculating section 7, etc. can also be formed into one block.

The display section 9 is a multipurpose information display device using a CRT, EL display, liquid crystal display, or the like, and displays the position, direction, etc. of the self-propelled vehicle based on the signals input from the route calculation section 3.

Next, the operation of the first embodiment of the present invention having the above structure will be explained with reference to FIGS. 2 and 3.

Now, assume that the vehicle is being driven along the route displayed on the display unit 9 from the intersection P1 to the intersection P3. At this time, the difference detection unit 4 compares the azimuth information input from the map storage unit 2 and the actual azimuth data input from the azimuth calculation unit 7 every time a predetermined distance is traveled, calculates the difference, and calculates the average value. The section 5 averages the difference values for a predetermined number of times, and the bias variable section 8 varies the correction value based on this average value.

Now, assume that accurate correction is made at the first specific point C1, and the correction value, that is, the bias level, is the XO value for the X component and the YO value for the Y component, as shown in FIG. While passing through area E in this state, the magnetization state of the vehicle body changes due to the influence of the disturbance magnetic field, and the orientation toward the second specific point C2 should originally be 01 degrees, but it becomes 01' degrees, causing an error. arise. This error value (θ-θ') is input to the average value calculation unit 5 and averaged together with the difference values obtained several times previously, and as a result, the bias level is an appropriate correction value x
o', yo' values are approximated. Furthermore, the third specific point C3
It goes without saying that if the bias level is not affected by a new disturbance magnetic field until reaching the XO' and YO' values, the bias level approximates the XO' and YO' values.

Second example A second preferred embodiment of the present invention will be explained with reference to FIG.

The second embodiment is almost the same as the first embodiment, but some differences will be explained in detail.

To summarize the differences, the first difference is that in the first embodiment, the direction information from the map storage unit 2 is output every time a predetermined distance is traveled, but in the second embodiment, the direction information is output on the road network. output only at selected locations. A second difference is that in the first embodiment, the difference detection unit 4 calculates the difference (-) with the azimuth data input from the azimuth calculation unit 7 every time azimuth information is input, but in the second embodiment In this example, the difference is calculated in synchronization with a timing signal from a timing section 10, which will be described later.A third difference is that the average value calculation section 5 is omitted in the second embodiment.

Hereinafter, a description of the same parts as in the first embodiment will be omitted, and a second embodiment of the present invention will be described based on FIG. 4.

The map storage unit 2 includes a road network data storage unit 21, a specific point direction output unit 22, and a specific point distance output unit 23, and the timing unit 1o includes a register circuit 11, a counter circuit 12, and an AND circuit 13. Furthermore, the difference detection section 41 has a timing signal input section from the timing section 10.

Next, each of the above configurations will be explained in detail.

The specific point azimuth output unit 22 outputs azimuth information of a selected point on the road network, for example, a point with a low possibility of receiving a disturbance magnetic field or a point where the road is relatively direct, to a subsequent difference detection unit 41. This is what is output. The specific point distance output unit 23 outputs distance information from a certain point, for example, the previous specific point to the current specific point, to the register circuit 11 at the subsequent stage.

The specific point distance output section 23 outputs distance information from a certain point, for example, from the previous specific point to the current specific point, to the register circuit 11 at the subsequent stage. The register circuit 11 is
The distance information signal from the specific point distance output section 23 is converted into a parallel signal and stored. Counter circuit 12
is for counting pulse signals from the distance sensor 1. The AND circuit 13 outputs a timing signal to the subsequent difference detection section 41 if the parallel signal stored in the register circuit 11 and the count value of the counter circuit 12 match. The difference detection section 41 includes an AND circuit 13
In synchronization with the timing signal input from This is what is output.

Although the average value calculation unit 5 is omitted in accordance with the second embodiment, the average value calculation unit 5 can be omitted as appropriate.
It may be added if the correction value fluctuates rapidly. Furthermore, although each configuration has been described using circuit blocks in the embodiments of the present invention, it goes without saying that it can be configured using a microcomputer program. Further, the direction detecting section may be any direction detecting section other than a geomagnetic sensor, such as a gyro type, a method based on radio wave reception, etc.

Effects of the present invention The present invention has the following effects due to the above-mentioned structural functions.

a) Error correction can be performed automatically without placing any burden on the occupants.

b) Correction can be made while the vehicle is in normal driving condition without requiring turning operation or the like for correction.

C) The number of corrections can be increased, and appropriate corrections are always made.

d) No open space is required for correction work.

e) If an average value calculation unit for correction values is interposed in the correction circuit,
Fluctuations in correction values can be alleviated.

[Brief explanation of the drawing]

FIG. 1 is an electrical block diagram showing a first preferred embodiment of the present invention. FIG. 2 is a map showing route guidance according to the first embodiment. FIG. 3 is an explanatory diagram showing direction correction according to the first embodiment. FIG. 4 is an electrical block diagram showing a second preferred embodiment of the present invention. FIG. 5 is an explanatory diagram showing azimuth correction according to a conventional technique. DESCRIPTION OF SYMBOLS 1... Distance sensor, 2... Map storage unit, 3... Route calculation unit, 4... Difference detection unit, 5... Average value calculation unit, 6... Geomagnetic sensor, 7...・Direction calculation section, 8...
・Bias variable section, 9... Display section, 10... Timing section Fig. 1 112 Fig. 3 Y

Claims (1)

[Claims] In a device that guides a vehicle on a route using azimuth data from an azimuth calculation unit and road network data from a map storage unit, when passing through a specific point on a road network, the azimuth is determined based on azimuth information of the specific point obtained from the map storage unit. An azimuth data correction circuit comprising means for correcting data on the output side of the azimuth calculation section and the map storage section.