JPH0363519A - Locator device initialization device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an initialization device for a locator device that detects the current position and traveling direction of a moving object such as a vehicle, and sets the initial position and initial direction of a locator device. It is something.

<Prior Art> Recently, various locator devices have been provided that display the current location of the vehicle together with a road map so that even drivers who are unfamiliar with the area can drive without getting lost.

The locator device is composed of a speed sensor, a direction detection sensor, a map memory, a display, and a computer.

Vehicle speed sensors and wheel speed sensors are currently used as speed sensors for vehicles.

Furthermore, as a direction detection sensor for a vehicle, a geomagnetic direction sensor that is compact and capable of detecting an absolute direction, or an angular velocity sensor that detects the angular velocity of a vehicle is used.

The above geomagnetic azimuth sensor has the advantage of being able to detect absolute orientation, but has the disadvantage that the output signal varies and errors occur when a strong magnetic field is received from the outside.

Further, although the angular velocity sensor has the advantage of being able to accurately detect the amount of change in orientation and being unaffected by external magnetic fields, it cannot detect the absolute orientation that serves as a reference.

Therefore, a method has been adopted in which a geomagnetic azimuth sensor and an angular velocity sensor are used together. That is, at the time of initial setting (when starting traveling), the output of the geomagnetic direction sensor at the initial position is detected and this is set as the initial direction, and after starting traveling, the output (angular velocity) of the angular velocity sensor is integrated. This detects the amount of change in direction from the start point of travel to the current location.

<Problems to be Solved by the Invention> However, the output of the geomagnetic orientation sensor varies as described above, and when the initial orientation is set by directly capturing the output of the geomagnetic orientation sensor at the initial position,
The error in the initial orientation is large, and as the vehicle continues to travel, this error accumulates, and in the end, it becomes impossible to know which point the current position is.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an initialization device for a locator device that makes it possible to accurately set the initial orientation and improve the accuracy of detecting the current position.

Means for Solving the Problems and Effects> In order to achieve the above object, the initialization device for the locator device of the first invention sets the output of the geomagnetic azimuth sensor at the start point of the travel as the initial orientation, and After the start, the output of the angular velocity sensor is integrated to calculate the amount of change in direction from the start point, and the distance traveled from the start point is calculated based on the output of the distance sensor, and the amount of change in direction and the distance traveled are calculated. The traveling trajectory, current position, and traveling direction of the moving body are detected based on the above-mentioned traveling start point, and the traveling start point is calculated based on this provisional initial bearing, with the initial bearing at the traveling start point as a temporary initial bearing. a storage means for storing the amount of change in direction and the travel route from the time to straight-ahead travel; a straight-ahead detection means for detecting whether the vehicle is traveling straight based on the output from the angular velocity sensor; and a straight-ahead detection signal is output for a certain period of time from the straight-ahead detection means. an average value calculation means for calculating the average value of the output of the geomagnetic direction sensor within this certain period of time, and the average value calculated by the average value calculation means and the travel starting point stored in the storage means. Based on the amount of change in direction until traveling straight, the true direction at the start point of travel is calculated, this true direction is set as the initial direction, and the start point of travel is stored in the storage means with this initial direction. The present invention is characterized in that it has a resetting means for correcting the traveling trajectory from to the current location.

The above first invention focuses on the property that although the output of the geomagnetic azimuth sensor varies, the average value of the output of the geomagnetic azimuth sensor when driving straight for a certain period of time indicates a stable azimuth.

That is, the straight-ahead detection means detects straight-ahead travel based on the output of the angular velocity sensor, and supplies a straight-ahead detection signal to the average value calculation means.

When the straight-ahead detection signal is manually input for a certain period of time, the average value calculation means calculates the average value of the output of the geomagnetic direction sensor within this certain period of time. This average value is accurate orientation data at the current location.

The initialization means calculates the true heading at the starting point of traveling based on this average value and the amount of change in heading from the starting point of traveling until traveling straight ahead, sets this as the initial heading, and sets the true heading to this initial heading. Based on this, the travel trajectory from the starting point to straight forward travel is corrected.

This makes it possible to accurately detect the travel trajectory from the travel start point to the current location, the current location, and the heading direction of the vehicle.

Further, the second invention sets the output of the geomagnetic azimuth sensor at the start point of travel as the initial direction, and after the start of travel, integrates the output of the angular velocity sensor to calculate the amount of change in direction from the start point of travel, In a locator device that calculates a travel distance from a travel start point based on the output of a distance sensor and detects the current position and traveling direction of a moving object based on the amount of change in orientation and the travel distance, A travel vector calculation means that calculates a travel vector based on the amount of change in orientation from the travel start point and the travel distance, with the orientation as a temporary initial orientation, and detects whether the vehicle is traveling straight based on the output from the angular velocity sensor. a straight-ahead detecting means; an average value calculating means for calculating an average value of the output of the geomagnetic direction sensor within the certain time when a straight-ahead detection signal is output from the straight-ahead detecting means; The angle difference between the average value calculated based on the provisional initial orientation and the orientation at the average value calculation point is calculated, and the travel from the travel start point calculated by the travel vector calculation means to the average value calculation point is calculated. The present invention is characterized by comprising an initializing means for rotating the vector by the above angle difference to calculate the current position and setting the current position and the average value as initial values.

According to the second aspect of the invention, the travel vector calculation means calculates the travel vector based on the amount of change in direction and travel distance accompanying travel. Then, the orientation at the average value calculation point calculated based on the temporary initial orientation by the initialization means,
Angular difference from the average value (i.e. heading error at the starting point)
is calculated, the travel vector from the travel start point to the average value calculation point is rotated by the angular difference, the current position is calculated, and this current position and the average value are set as initial values. That is, as in the first invention, since the travel trajectory is not stored, the storage capacity of the entire device can be reduced.

<Embodiment> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an initialization device according to an embodiment of the present invention. Note that this initialization device is an extracted part of the initialization function of the locator device.

The initialization device includes a keyboard for inputting initial turn-off conditions such as a road map around the current location and the current location (initial position), a wheel speed sensor 1 that detects the number of rotations of the wheels, and the angular velocity of the vehicle. an angular velocity sensor 2 that detects the horizontal component of the earth's magnetic field (absolute orientation), a geomagnetic azimuth sensor 3 that detects the traveling direction of the vehicle with respect to the horizontal component of the earth's magnetism (absolute azimuth), a map memory 4 that stores a road map within a predetermined range, a display 5, and a keyboard. When the initial conditions are input from 6, the initial orientation is temporarily set,
It has a computer 7 that performs various arithmetic controls such as detecting the amount of change in direction, detecting straight running, and setting the true initial direction.

The computer 7 includes an azimuth change detection section 8 as a storage means, a straight running detection section 9, an average value calculation section 0, and a travel route calculation section 11 as an initialization means.

The azimuth change detection unit 8 integrates the output of the angular velocity sensor 2 to detect the amount of change in the azimuth from the initial position, and determines the traveling trajectory (
Time series data of travel distance and direction changes) are stored.

The straight-ahead traveling detecting unit 9 compares the output of the angular velocity sensor 2 with a constant value, and if the absolute value of the output of the angular velocity sensor 2 is less than or equal to the constant value, it is determined that the vehicle is traveling straight. This straight-ahead detection signal is supplied to the average value calculation section 10.

When the straight-ahead detection signal is continuously supplied for a certain period of time, the average value calculation unit IO sequentially adds the outputs of the geomagnetic azimuth sensor 3 and calculates the average value of the outputs.

This average value is sent to the travel route calculation unit 1 along with the processing end flag.
Pass it to 1. Further, if the straight-ahead detection signal is not input continuously for a certain period of time, the added data is cleared.

The running route calculation unit 11 calculates the average value calculation unit IO after the start of running.
When the processing completion flag is supplied from , the average value is taken in as azimuth data, the traveling trajectory from the initial position stored in the azimuth change detection unit 8 is taken in, and the average value and the amount of azimuth change up to straight traveling are calculated. Based on this, the true orientation at the initial position is determined and this is reset as the initial orientation.

Next, the travel trajectory up to the current location is corrected based on the reset initial orientation to determine the travel route from the initial location and the current location (see FIG. 2). The corrected driving route, vehicle position, and traveling direction from the initial position to the current position are then displayed on the display 5 together with the road map stored in the map memory 4.

The operation of the initialization device having the above configuration will be explained based on the schematic diagram of the travel route in FIG.

First, the traveling route calculation unit 11 receives an initial setting input and sets the output of the geomagnetic azimuth sensor 3 at the initial position O as a temporary initial azimuth.

Then, the azimuth change detection unit 8 stores time series data (traveling trajectory) based on the amount of azimuth change and the traveling distance from the initial position to the straight running.

Next, when the vehicle continues to drive straight for a certain period of time and reaches point A'' (estimated current position), the average value calculation unit IO calculates the average value of the output of the geomagnetic direction sensor 3. This average value is Vehicle heading data at the current location (arrow a in the figure)
). Geomagnetic direction sensor 3 at 0 point now
If there is an error in the azimuth data a, the azimuth data a will be bent with respect to the broken line as shown in the figure.

Next, the travel route calculation unit 11 calculates the true orientation at the initial position based on the average value and the amount of change in orientation from the initial position to straight running stored in the orientation change detection unit 8, and calculates the true orientation at the initial position. Reset as the initial orientation. That is, initialize it. Then, based on the initial orientation that has been initialized, the travel route (indicated by the solid line in the figure) from the initial position stored in the orientation change detection unit 8 to the current location is corrected to the true current position (point A in the diagram). seek.

According to the initialization device of the above embodiment, the average value of the output of the geomagnetic azimuth sensor 3 when traveling in a straight line is determined, and the true initial orientation is set based on this average value. Even if there is an error in the orientation due to variations in the output of the geomagnetic orientation sensor 3, the orientation can be reset to an accurate orientation later. In addition, the azimuth change detection unit 8 stores a travel trajectory from the initial position to straight forward travel, and by correcting this travel trajectory, the travel route and current position can be accurately detected.

FIG. 3 is a diagram showing an embodiment of an initialization device according to another invention, and the difference from the embodiment shown in FIG. That is what we are doing.

The traveling vector calculation unit I2 calculates the amount of change in direction from the initial position by integrating the angular velocity from the angular velocity sensor 2, using the output of the geomagnetic direction sensor 3 at the initial position as a reference, and calculates the amount of change in direction from the initial position by integrating the angular velocity from the angular velocity sensor 2. The traveling distance is calculated based on the rotational speed of the vehicle, the traveling vector is calculated at fixed distances or fixed time intervals based on the amount of change in direction and the traveling distance, and the traveling vector is sequentially integrated.

FIG. 4 is a schematic diagram of a travel route for explaining the operation of the initialization device shown in FIG. 3.

The travel route calculation unit 11 obtains the orientation at the initial position O from the geomagnetic orientation sensor 3 in the same manner as described in FIG. 2, and uses this as a temporary initial orientation. The traveling vector calculation unit 12 integrates the traveling vector from the initial position to the estimated current position A'. Through this integration, a straight line vector (indicated by a broken line in the figure) connecting the initial position 0 and A' is obtained. Furthermore, the estimated orientation at point A' is calculated based on the tentative initial orientation that includes an error. Then, in the travel route calculation unit 11, the true current position (the same Figure point A)
can be found. This current position and average direction a
Set as the true initial value.

In the above embodiment, it is not possible to calculate the driving route from the initial position to the current location, but since there is no need to memorize the driving trajectory, the configuration can be simpler than in the example shown in FIG. .

In the above embodiment, the azimuth change amount is calculated using the angular velocity sensor, but it is also possible to install wheel speed sensors on both the left and right wheels.
It is also possible to calculate the turning angle of the vehicle based on the rotational speed difference between the left and right wheels, and to determine the amount of change in direction from this turning angle. Various other design changes can be made without departing from the gist of the invention.

<Effects of the Invention> According to the first invention described above, by calculating the average value of the output of the geomagnetic azimuth sensor when the vehicle is traveling straight for a certain period of time using the average value calculation means, and using this as the azimuth data, A stable orientation can be obtained by averaging variations in the output of the geomagnetic orientation sensor. Furthermore, initialization
The true initial heading at the starting point is calculated based on this stable heading (average value) and the amount of change in heading up to the straight-ahead run17, and the running trajectory from the start point to the straight-ahead run is corrected. As a result, the initial orientation can be set accurately, and the detection accuracy of the current position can be improved.

Further, according to the second invention, the angular difference between the azimuth calculated based on the initial azimuth at the travel start point and the average value, that is, the error at the travel start point, is calculated, and the vehicle travels by the amount of this error. The current position is calculated by rotating the traveling vector from the starting point to the average value calculation point, and by setting this current position and the average value as the initial value, the traveling trajectory is not memorized, so the current position and traveling direction can be calculated. It is possible to make accurate settings, and the storage capacity of the entire device can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an initialization device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a running route for explaining the operation of the initialization device shown in FIG. 1, and FIG. A diagram showing an embodiment of the initialization device according to another invention. FIG. 4 is a schematic diagram of a travel route for explaining the operation of the initialization device of FIG. 3 above. 1: Wheel speed sensor, 2: Angular velocity sensor, 3: Geomagnetic direction sensor, 8: Direction change detection section, 9: Straight running detection section, l
O: Average value calculation section, tl: Traveling route calculation section, 12: Traveling vector calculation section 1

Claims (1)

[Scope of Claims] 1. The output of the geomagnetic azimuth sensor at the start point of travel is set as the initial orientation, and after the start of travel, the output of the angular velocity sensor is integrated to calculate the amount of change in orientation from the start point of travel,
In a locator device that calculates a travel distance from a travel start point based on the output of a distance sensor, and detects a travel trajectory, current position, and traveling direction of a moving object based on the amount of change in orientation and travel distance, Let the initial orientation at the point be a temporary initial orientation,
A storage means for storing the amount of change in direction from the starting point of travel and the travel trajectory based on this provisional initial direction; straight-ahead detection means for detecting whether the vehicle is traveling straight based on the output from the angular velocity sensor; and straight-ahead detection means. an average value calculation means for calculating the average value of the output of the geomagnetic azimuth sensor within the certain period of time when the straight-ahead detection signal is outputted from the above for a certain period of time; The true heading at the starting point is calculated based on the amount of change in heading from the stored running start point to straight running, and this true heading is set as the initial heading, and this initial heading is stored in the storage means. An initialization device for a locator device, comprising: initialization means for correcting a travel trajectory from a travel start point to a current location stored in the locator device. 2. Set the output of the geomagnetic orientation sensor at the start point of travel as the initial orientation, and after the start of travel, integrate the output of the angular velocity sensor to calculate the amount of change in orientation from the start point of travel,
In a locator device that calculates a travel distance from a travel start point based on the output of a distance sensor and detects the current position and traveling direction of a moving object based on the amount of change in orientation and the travel distance, Set the direction as a temporary initial direction,
A travel vector calculation means for calculating a travel vector based on the amount of change in direction from the travel start point and the travel distance; A straight-ahead detection means for detecting whether the vehicle is traveling straight based on the output from the angular velocity sensor; A straight-ahead detection means an average value calculation means for calculating the average value of the output of the geomagnetic direction sensor within the certain period of time when a straight-ahead detection signal is output from the Calculate the angular difference from the azimuth at the average value calculation point calculated based on the azimuth, and rotate the travel vector from the travel start point to the average value calculation point calculated by the travel vector calculation means by the angular difference. An initialization device for a locator device, comprising: initialization means for calculating a current position and setting the current position and an average value as initial values.