JP3337866B2 - Vehicle direction detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth detecting device for a vehicle which detects a traveling azimuth of a vehicle by using geomagnetism.

[0002]

2. Description of the Related Art Conventionally, in this type of vehicle azimuth detecting device, an X-axis component of an input magnetic vector and a Y
An axial component is detected, and a previously stored magnetization amount (offset amount) in the X-axis direction and the Y-axis direction of the vehicle is subtracted from the detected X-axis direction component and Y-axis direction component. The traveling direction of the vehicle is detected based on the detected magnetic component that has been subtracted.

That is, a magnetic sensor having two orthogonal (X, Y axis) magnetic detecting elements (X-axis coil, Y-axis coil) is coupled with the X-axis in the vehicle length direction (vehicle traveling direction).
In addition, the Y-axis is set in the width direction of the vehicle, and the X- and Y-axes are arranged on the vehicle while being held so that the plane formed by the X and Y axes becomes a horizontal plane. Here, the angle between the traveling direction (X axis) of the vehicle and the geomagnetic vector (horizontal component) is θ, the absolute value of the geomagnetic vector (horizontal component) is R, the magnetization amount of the vehicle in the X axis direction is α,
Assuming that the amount of magnetization in the Y-axis direction of the vehicle is β, the X-axis direction component Vx and the Y-axis direction component Vy of the input magnetic vector detected by the magnetic sensor are expressed by the following equations (1) and (2). Vx = R · cos θ + α (1) Vy = R · sin θ + β (2)

[0004] In other words, if Vx and Vy when the vehicle turns around in uniform geomagnetism are drawn on a coordinate plane, a circle (hereinafter, this circle is called an azimuth circle) is drawn as shown in FIG. It is. By the way, the coordinates of the center point C0 of the azimuth circle are (α, β)
And the radius is R. Here, the magnetization amounts α and β of the vehicle
Can be detected by turning around the vehicle. For example, X-axis azimuth circle, the Y-axis, respectively, the maximum value _{(Vx ma x, Vy max)} , the minimum value (Vx _min,
Vy _min ), the magnetization amounts α and β can be obtained from the following equations (3) and (4). _{α = (Vx max + Vx min} ) / 2 ··· (3) β = (Vy max + Vy min) / 2 ··· (4) Accordingly, stored in advance as an offset amount magnetizing amount alpha and beta For example, the instantaneous traveling direction θ of the vehicle can be obtained from the following equation (5). θ = tan ⁻¹ [(Vy−β) / (Vx−α)] (5)

However, in this case, since the direction of the vector from the center point C0 of the azimuth circle to the coordinate point (Vx, Vy) detected by the magnetic sensor is determined, the magnet may be moved closer to the vehicle or the vehicle may be exposed to a strong magnetic field. When the magnetization amounts α and β change due to passing through, for example, a detection error occurs.
That is, as shown in FIG. 5, the center point C0 of the azimuth circle is C
When shifted to 1, will be detected as a theta despite the actual heading is theta ', detection error of θ'-θ = θ _E occurs. In such a case, it is conceivable that the vehicle turns around again and the amounts of magnetization α and β are obtained again. However, there is almost no large place suitable for orbital turning in an urban area, and it is severe to force a user to correct a detection error due to frequent orbital turning. Therefore, a vehicle direction detection device that can automatically correct a detection error due to a change in the amount of magnetization without forcing the user to perform frequent round turns has been proposed.

In this azimuth detecting device for a vehicle, each time a predetermined time elapses, a coordinate point indicated by a detected X-axis direction component and a detected Y-axis direction component is extracted as a storage candidate coordinate point.
Then, the extracted storage candidate coordinate point is compared with each of the already stored storage confirmed coordinate points, and the storage candidate coordinate point is determined for each of the areas (non-selected areas) defined around each of the storage confirmed coordinate points. If not, the storage candidate coordinate points are collected as storage determined coordinate points. When the number of the stored coordinate points discretely collected as the correction data is equal to or more than a predetermined number (for example, four),
The center point of an arc passing through these stored fixed coordinate points is determined, the amount of magnetization in the X-axis direction and the Y-axis direction of the vehicle is determined from the coordinate position of the center point, and the determined amount of magnetization is used as the new X-axis value of the vehicle. It is updated and stored as the magnetization amounts α ′ and β ′ in the direction and the Y-axis direction.

[0007]

The change of the input magnetic vector is not limited to the change in the geomagnetic field, but also the traveling on the steel plate at the construction site, the passage under the high voltage line, the lateral passage of the magnetized vehicle, the overpass and the bridge. It changes depending on the running, on / off of the onboard electrical equipment, and the like. However, in the above-described conventional azimuth detecting device for a vehicle, it is difficult to distinguish between an actual geomagnetic change and a magnetic change caused by something other than the geomagnetism (hereinafter, referred to as a magnetic change caused by disturbance magnetism), and the storage candidate coordinate point is not determined by the disturbance magnetism. The storage candidate coordinate point is determined as the storage confirmed coordinate point even though it is no longer located in the selected area. Therefore, the arc center point of the storage <br/> determined coordinate point obtained when the storage <br/> determined coordinate point is not less than the predetermined number, that is, the X-axis direction and the Y-axis direction of the vehicle to be redetermined Does not match the current magnetization amounts α ′ and β ′ in the X-axis direction and the Y-axis direction of the vehicle, and a detection error occurs.

An azimuth detecting device for a vehicle in consideration of disturbance magnetism is disclosed in Japanese Patent Application Laid-Open No. 2-29319. In this azimuth detecting device for a vehicle, a geomagnetic constant is calculated from geomagnetic azimuth data collected during one round of turning, and a geomagnetic azimuth that changes momentarily during one round of turning is obtained using the value. Similarly, the turning angle of the vehicle, which changes momentarily during one turn, is also obtained. Thereafter, a linearity error of the geomagnetic azimuth based on the turning angle is obtained from the geomagnetic azimuth and the turning angle during one round of rotation, and the inclination of the axis in the axial direction (elliptical (azimuth circle)) is determined so as to reduce the error. ] Is corrected. As a result, even if there is an error due to disturbance magnetism in the geomagnetic azimuth data obtained first, the influence can be reduced and an appropriate axial direction can be obtained, so that a more reliable detection of the traveling azimuth becomes possible. .

However, this azimuth detecting device for a vehicle can reduce the influence of the disturbance magnetism, but corrects the axial direction so as to minimize the error with respect to the magnetic azimuth data to which the disturbance magnetism is added. However, the accuracy of correcting the detection error cannot be said to be high. In other words, the error due to the disturbance magnetism added when the geomagnetic azimuth data is collected during one round of rotation can be reduced by correcting the axial direction so as to reduce the linearity error. Is not removed at all, a large correction error remains, and the correction accuracy of the detection error decreases. Also,
In this azimuth detecting device for a vehicle, the vehicle must be turned once, and the user is forced to correct a detection error due to frequent turning.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to correct a detection error due to a change in the amount of magnetization without forcing a user to perform frequent orbital turns. It is an object of the present invention to provide an azimuth detecting device for a vehicle which can automatically perform the above-mentioned operation, and can correct the detection error with high accuracy while eliminating the influence of disturbance magnetism as much as possible.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an X-axis component of an input magnetic vector.
And Y-axis direction components are detected periodically, and the detected X-axis
The heading of the vehicle based on the direction component and the Y-axis direction component
Heading detecting means for detecting the direction, and the X-axis direction detected this time
Candidate to store coordinate points indicated by directional component and Y-axis direction component
Extracted as coordinate points and already stored with this storage candidate coordinate point
Is compared with each of the stored fixed coordinate points, and the storage candidate
Coordinate points are defined centering on each stored coordinate point
If it is not located in any of the areas, the storage candidate
Collecting reference points as stored fixed coordinate points
Collection means and the storage fixed coordinate point collection means.
If the number of stored confirmed coordinate points exceeds a predetermined number,
How to proceed based on the coordinate position of the collected memory fixed coordinate point
Detection head for correcting the traveling direction of the vehicle detected by the position detection means.
The line azimuth correcting means and the storage fixed coordinate point collecting means are set for a predetermined time.
If the next memorized coordinate point cannot be collected within
Correction to prohibit correction of detected traveling direction by direction correction means
Prohibition means .

[0012]

According to the present invention, therefore, the presently detected
The coordinate points indicated by the X-axis component and the Y-axis component are described.
This is extracted as a memory candidate coordinate point.
Is compared with each stored coordinate point stored in
Memory candidate coordinate points are determined with each memory determined coordinate point as the center.
If it is not located in any of the
The storage candidate coordinate points are collected as storage fixed coordinate points. So
Then, the number of collected memory-determined coordinate points exceeds a predetermined number
Based on the coordinate positions of these stored memory fixed coordinate points.
And the detected traveling direction is corrected. In this case, within a predetermined time
If the next stored fixed coordinate point cannot be collected
Is prohibited. For example, it has been collected
The stored fixed coordinate point is discarded , and correction of the detected traveling direction using the stored fixed coordinate point is prohibited.

[0013]

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. FIG. 2 is a system configuration diagram of a vehicle azimuth detecting device showing one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a magnetic sensor mounted on a vehicle, and 2-1 and 2-2 denote X-axis direction components V of an input magnetic vector detected by the magnetic sensor 1.
An A / D conversion circuit 3 which receives x and Y-axis direction components Vy as inputs, and 3 an X-axis direction component Vx and a Y-axis direction component Vy converted into digital values by the A / D conversion circuits 2-1 and 2-2. And a display device such as an LED or LCD panel for displaying the traveling direction of the vehicle obtained by the processing operation in the arithmetic circuit 3, and a reference numeral 5 for the vehicle. A vehicle speed sensor 6 for transmitting a pulse signal (vehicle speed signal) corresponding to the traveling speed of the vehicle, and a waveform shaping circuit 6 for adjusting the signal level of the vehicle speed signal from the vehicle speed sensor 5 and removing noise, etc.

The magnetic sensor 1 has X as a magnetic detecting element.
Amplify the detected voltage according to the X-axis component and the Y-axis component of the input magnetic vector generated in the axis coil 1-1 and the Y-axis coil 1-2 and the input magnetic vector generated in the X-axis coil 1-1 and the Y-axis coil 1-2. An X amplifier 1-3 and a Y amplifier 1-4 are provided. The arithmetic circuit 3 includes a memory (not shown)
Are provided, and the amounts of magnetization α and β in the X-axis direction and the Y-axis direction of the vehicle are stored in this memory.

Next, the characteristic operation of the vehicle azimuth detecting device will be described with reference to the flowchart shown in FIG. The arithmetic circuit 3 calculates the X-axis direction components Vx and Y of the input magnetic vector detected by the magnetic sensor 1.
The A / D conversion value of the axial component Vy is read (step 1).
01), an averaging process is performed (step 102). The average values of the X-axis direction component and the Y-axis direction component obtained by this averaging process are defined as VX and VY. Further, the controller reads the magnetization amounts α and β (initial values) of the vehicle in the X-axis direction and the Y-axis direction stored in the memory, and adjusts the amplitude and offset of the X-axis direction component VX and the Y-axis direction component VY. This is performed (step 103), and the current traveling direction θ (m) is calculated according to the following equation (6) (step 104). In this case, the coordinates of the center point of the azimuth circle (reference point of the azimuth circle) are (α,
β). θ (m) = tan ⁻¹ [(VX−β) / (VY−α)] (6)

Then, the arithmetic circuit 3 checks whether or not "initial (operation start state)?" (Step 10).
5) If the operation is in the operation start state, the process proceeds to step 107 without passing through step 106. If the operation is in the normal operation state, the process proceeds to step 107 via step 106. Step 106
Then, the amount of magnetic change is checked, and if the amount of magnetic change is equal to or larger than the predetermined upper limit _GMAX , it is determined that there is an abnormality, and the routine proceeds to step 116. In this embodiment, step 106
The upper limit value G _MAX of the magnetic change amount is set to be constant over the entire vehicle speed range.

That is, in step 106, every time the A / D conversion value of the X-axis direction component Vx and the Y-axis direction component Vy of the input magnetic vector is sampled, the X-axis direction components Vx and Y detected by the previous sampling are sampled. Axial component Vy and X detected by this sampling
Disturbance when the axis the difference between the direction component Vx and Y-axis direction component Vy calculated as the magnetic variation ΔVx and Delta] Vy, becomes the magnetic variation ΔVx and an upper limit at least one of a predetermined of Delta] Vy G _MAX or more It is determined that there is an instantaneous magnetic change due to magnetism, and the routine proceeds to step 116, where the correction data and the time measurement counter are cleared. The clearing of the correction data and the time measurement counter in step 116 will be described later.

In step 106, the magnetic change amount ΔV
Checking x and ΔVy means checking whether a magnetic change caused by turning or a magnetic change caused by disturbance magnetism. When the vehicle normally turns at an intersection or the like, there is an upper limit to the lateral G that can be controlled by a general driver. In consideration of this, a critical turning angular velocity according to the vehicle speed is obtained. Since the azimuth circle radius R is set in advance, when a turning state is assumed, magnetic variation ΔVx and ΔVy limit magnetic variation G _{ma x} is determined according to the vehicle speed.

[0020] If the normal turning, the magnetic variation ΔVx and ΔVy are not exceed the limit magnetic variation G _max, if at least one magnetic variation ΔVx and ΔVy exceeds the limit magnetic variation G _max, It can be regarded that _Gmax has been exceeded by disturbance magnetism, not by turning. Ideally, he should determine the upper limit value G _MAX for magnetic variation ΔVx and ΔVy the vehicle speed as parameters, is often while the vehicle is turning a deceleration state, to obtain a magnetic variation ΔVx and ΔVy The vehicle speed at that time may not match the detected vehicle speed. Therefore, in this embodiment, it defines a maximum limit magnetic variation G _max of the vehicle throughout the upper limit value G _MAX for magnetic variation ΔVx and Delta] Vy, i.e. the upper limit value G _MAX used in step 106. As a result, the upper limit G _MAX
Is determined as a non-turning state, and it is possible to clearly discriminate between a magnetic change due to a terrestrial magnetism and a magnetic change due to disturbance magnetism when turning at a general intersection or the like.

In step 107, the vehicle speed detected based on the vehicle speed signal from the vehicle speed sensor 5 is checked. If the detected vehicle speed is 2.8 to 35km / h, step 10 is executed.
Proceed to 8. At step 108, a time measurement counter (not shown) counts up. Then, the count value of the time counter is checked (step 10).
9) If not overflowing, go to step 110. In step 110, coordinate points (Vx, Vy) indicated by the X-axis direction component Vx and the Y-axis direction component Vy of the input magnetic vector fetched in step 101 are set as storage candidate coordinate points.

The storage candidate coordinate points (Vx, Vx
y) and each of the stored fixed coordinate points (Xt
(N), Yt (n)), and the storage candidate coordinate point (V
x, Vy) is the stored fixed coordinate point (Xt (n), Yt
(N)), if it is not located in any of the non-selected areas defined around the center, the storage candidate coordinate point (Vx, V
y) is the next stored coordinate point (Xt (n), Yt (n))
(Step 111).

Referring to FIG. 3, the stored coordinate point (Xt
(N), Yt (n)) will be described in detail.
Now, the memory determined coordinate point P1 (Xt (1), Yt (1)),
P2 (Xt (2), Yt (2)), P3 (Xt (3),
Yt (3)) is determined, and the storage candidate coordinate point P4 (Vx, Vy) is extracted in step 110. In this case, square non-selection areas S1, S2, and S3 centering on P1, P2, and P3 are defined for the storage determined coordinate points P1, P2, and P3. The storage candidate coordinate point P4 is not located in any of the non-selected areas S1, S2, S3. Therefore, in this case, the storage candidate coordinate point P4
Is determined as the stored fixed coordinate point P4 (Xt (4), Yt (4)).

In step 111, storage candidate coordinate points (Vx,
If Vy) is determined as the storage confirmed coordinate point (Xt (n), Yt (n)), the time measurement counter whose count value has been increased in step 108 is cleared (step 1).
12). Then, the stored fixed coordinate point (Xt (n), Yt
If four (n)) are collected, YE in step 113
The process proceeds to step 114 according to S. In step 114,
The center point of the arc passing through the four stored fixed coordinate points (Xt (n), Yt (n)) discretely collected as correction data is obtained as the reference point of the azimuth circle. Then, the amount of magnetization of the vehicle in the X-axis direction and the Y-axis direction is obtained from the coordinate position of the reference point of the azimuth circle, and the obtained amount of magnetization is calculated as a new X
Update and store the magnetization amounts α ′ and β ′ in the axial direction and the Y-axis direction (step 115).

Then, the process proceeds to a step 117, wherein the traveling azimuth θ (m) calculated in the step 104 is displayed and outputted. The magnetization amounts α ′ and β ′ updated and stored in step 115, that is, the coordinates (α ′ and β ′) of the reference point of the azimuth circle are determined by the traveling azimuth θ in step 104 in the next sampling cycle.
Used when calculating (m). If the storage candidate coordinate point is not determined as the storage confirmed coordinate point in step 111 , or if four storage determination coordinate points (Xt (n), Yt (n)) are not collected in step 113, the azimuth circle is not determined. The process immediately proceeds to step 117 without calculating and updating the reference point. Thereby, when the vehicle turns, the stored fixed coordinate points are automatically collected, and the stored fixed coordinate points are located at points apart from each other.
The reference point of the azimuth circle, that is, the magnetization amounts α ′ and β ′ are calculated with high accuracy.

Here, the state of the geomagnetism changes due to the influence of disturbances, vehicle conditions, etc., even at different locations or at the same location. If the same level of disturbance magnetism is applied for a relatively long time during running, it cannot be detected as the amount of magnetic change in step 106. In this case, the coordinate point (Vx, Vy) of the input magnetic vector to which the disturbance magnetism is added is determined in step 110.
Are extracted as storage candidate coordinate points.

Now, it is assumed that the vehicle is traveling straight, and the stored fixed coordinate point P1 has been collected as correction data. At this time, when the coordinate point (Vx, Vy) of the input magnetic vector to which the disturbance magnetism is added is extracted as the storage candidate coordinate point P2 ′ (see FIG. 3), the non-selection area S1 centered on the storage fixed coordinate point P1. Is not located at the storage candidate coordinate point P2 ′, the storage candidate coordinate point P2 ′ is
Determined as 2 '. Then, by the next sampling, the coordinate point (Vx, Vy) of the input magnetic vector to which the disturbance magnetic field of the same level as that of the previous sampling is added is extracted as the storage candidate coordinate point P3 '. However, since the storage candidate coordinate point P3 'in this case is located in the non-selection area S2' centered on the storage confirmed coordinate point P2 ', it is not determined as the storage confirmed coordinate point. In the next sampling, the storage candidate coordinate point P3 'is similarly extracted, but this is not determined as the storage confirmed coordinate point.

On the other hand, the time measurement counter that has been cleared after determining the determined storage coordinate point P2 'is counted up when the storage candidate coordinate point P3' is extracted in the next sampling cycle. The storage candidate coordinate point P3 'is extracted every time the A / D conversion data is sampled, but the storage candidate coordinate point P3' cannot be determined as the storage fixed coordinate for a predetermined time (5 seconds in this embodiment). When the time elapses, the time measurement counter overflows. When the time counter overflows, the process proceeds to step 116 in response to YES in step 109. In step 116, the correction data and the time measurement counter collected so far are cleared. As a result, the stored determined coordinate points P1 and P2 ′ that have been collected up to that point are discarded, and correction of the detected traveling direction using the collected correction data is prohibited.

That is, in the present embodiment, it is considered that the next stored coordinate point is determined within 5 seconds when turning at an ordinary intersection, and the next stored coordinate point is not determined even after 5 seconds. In this case, it is determined that the collection of the stored coordinate points is performed in the non-turning state, and the correction data collected so far is discarded. Thus, even if the same level of disturbance magnetism is applied for a relatively long time, that is, step 106
Even if it is not possible to detect the disturbance magnetism as the magnetic change in the above, the influence of the disturbance magnetism can be eliminated.

In the above description, the storage candidate coordinate point P
The state in which 3 ′ cannot be determined as the memory confirmed coordinate point has been described as having elapsed for 5 seconds or more.
Even if 3 ′ is determined as a storage-determined coordinate point, if a state in which the next storage-candidate coordinate point P4 ′ cannot be determined as a storage-determined coordinate point has elapsed for 5 seconds or more, the storage candidate coordinate point P3 ′.
The correction data is cleared in the same manner as in the above case. In the present embodiment, time monitoring by the time measurement counter is performed three times until four stored fixed coordinate points are obtained.

In this embodiment, when the vehicle speed reaches the vehicle speed equivalent to a stop (less than 2.8 km / h), it is determined that the vehicle is not turning, and the process immediately proceeds to step 117. As a result, time monitoring by the time counter and collection of correction data are temporarily suspended. That is, when the vehicle speed reaches the vehicle speed equivalent to stopping, the correction of the detected traveling direction is prohibited until the vehicle speed becomes equal to or higher than the vehicle speed equivalent to stopping. For this reason, in the present embodiment, for example, when the vehicle stops to wait for a pedestrian to cross when turning at an intersection, highly reliable correction data collected up to that point is discarded. No inconvenience occurs.

When the vehicle is at a standstill, no magnetic change is possible. However, a magnetic field change may occur due to a situation of waiting for a train at a railroad crossing or the like, or a lateral passage of a magnetized vehicle while waiting for a traffic light. In this embodiment, when the vehicle is stopped, the collection of correction data is interrupted, so that the influence of disturbance magnetism due to a change in magnetic field can be eliminated. In this embodiment, since the measurement processing time in the vehicle speed detection processing becomes longer at a low speed, the vehicle speed corresponding to a stop is set to less than 2.8 km / h.

In this embodiment, the vehicle speed is 35 km / h.
If so, it is determined that the vehicle is not turning, and the process proceeds to step 116 to clear the correction data and the time measurement counter. That is, in the present embodiment, it is assumed that the vehicle does not turn at 35 km / h or more at a general intersection. As a result, the magnetic field change during traveling at 35 km / h or more is not a magnetic field change caused by turning, but a disturbance component such as an overpass or a bridge during straight traveling. And the vehicle speed is 35k
If it is more than m / h, there is a risk that the correction data collected so far may include the influence of disturbance magnetism. Therefore, the correction data is discarded, and the subsequent correction data is collected. Interrupt.

If it is determined in step 106 that the amount of magnetic change is abnormal, the process also proceeds to step 116. In this case, however, there is a danger that the correction data collected so far includes the influence of disturbance magnetism. Therefore, the correction data is discarded.

[0035]

As is apparent from the above description, according to the present invention , the next stored coordinate point is collected within a predetermined time.
If not possible, the memory-determined coordinate points collected so far
Is discarded, etc.
Frequent orbital turns because correction of the detected heading direction is prohibited
Changes in the amount of magnetization without forcing the user to perform
In addition to enabling automatic detection error correction,
When the same level of disturbance magnetism is applied for a relatively long time
In this case, the detection error can be corrected with high accuracy by eliminating the influence of disturbance magnetism .

[0036]

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a characteristic operation in the vehicle direction detection device shown in FIG. 2;

FIG. 2 is a system configuration diagram of a vehicle azimuth detecting device according to an embodiment of the present invention.

FIG. 3 is a diagram specifically illustrating a process of determining a storage confirmed coordinate point in the azimuth detecting device for a vehicle.

FIG. 4 is a diagram showing an azimuth circle drawn on a coordinate plane by outputs Vx and Vy of a magnetic sensor when a vehicle turns around in uniform geomagnetism.

5 is a diagram showing a state where a center point C0 of the azimuth circle shown in FIG. 4 is shifted to C1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic sensor, 1-1 ... X-axis coil, 1-2 ... Y-axis coil, 1-3 ... X amplifier, 1-4 ... Y amplifier, 2-1
2-2 A / D conversion circuit, 3 arithmetic circuit, 4 display device, 5 vehicle speed sensor, 6 waveform shaping circuit.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yutaka Imai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-2-293619 (JP, A) JP-A-6-167347 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01C 17/28 G01C 17/38 G01C 21/00

Claims (1)

(57) [Claims] 1. A component in the X-axis direction and the Y-axis direction component of the input magnetic vector periodically detected, traveling direction detection for detecting the traveling direction of the vehicle based on the detected X-axis direction component and the Y-axis direction component Means and X-axis component and Y-axis component detected this time.
The extracted coordinate points are extracted as candidate memory coordinate points.
The complementary coordinate points and each of the stored fixed coordinate points
Compare, and the memory candidate coordinate point is centered on each memory determined coordinate point.
Not located in any of the areas defined as
In this case, the storage candidate coordinate points are collected as the storage confirmed coordinate points.
Storage coordinate point collecting means for storing the memory confirmation coordinate points collected by the storage fixed coordinate point collection means.
If the number of fixed coordinate points exceeds a predetermined number,
The heading detection based on the coordinate position of the stored fixed coordinate point
Detected heading to correct heading of vehicle detected by means
The correction unit and the storage-determined coordinate point collection unit perform the next storage confirmation within a predetermined time.
If the fixed coordinate points cannot be collected,
A azimuth detecting device for a vehicle, comprising: a correction prohibiting unit for prohibiting correction of a detected traveling azimuth by a step .