JPH01201115A - Azimuth sensor - Google Patents

Abstract

PURPOSE:To output invariably proper azimuth data by comparing signals from magnetic sensors. CONSTITUTION:The magnetic sensors 1A and 1B are so set that DELTAthetaA=DELTAthetaB in the absence of a disturbance element. If there is a disturbance element, DELTAthetaAnot equal to DELTAthetaB. A comparing means 2 compares signals DELTAthetaA and DELTAthetaB with each other and outputs a comparison result 2a of equality or nonequality. When the result 2a indicates that DELTAtheta=DELTAthetaB, an arithmetic means 3 processes azimuth data 3a according to the signal DELTAthetaA from a sensor 1A. When the result 2a indicates that DELTAthetaAnot equal to DELTAthetaB, on the other hand, the means 3 processes the azimuth data 3a by an arithmetic processing routine. Consequently, even if a signal is erroneous, the proper azimuth data is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an azimuth sensor used in a self-contained navigation system, and particularly to an azimuth sensor mounted on an automobile.

<Conventional technology> With the adoption of an autonomous navigation system, the position of a car, which was previously determined by the driver (or navigator) of the car, can be determined by the driver (or navigator).
It is now possible to automatically detect the direction or distance the vehicle is traveling, and notify the driver based on this detection data and map information.

This independent demonstration system uses data from two types of sensors. The first sensor is a distance sensor, also called a speed sensor. This is a sensor that calculates travel distance by integrating vehicle speed. The second sensor is a direction sensor, which indicates the direction in which the vehicle is traveling. As a direction sensor,
Examples include a sensor called a compass, such as a laser gyro, and a magnetic sensor that outputs a signal (magnetic information) proportional to an external magnetic field (terrestrial magnetism). Since the above-mentioned compass is large and expensive, a magnetic sensor is suitable for a self-contained vehicle demonstration system. This magnetic sensor can output displacement of the earth's magnetic field as a signal, and has been highly evaluated for its accuracy.

<Problem that the invention seeks to solve> By the way, the conventional technology has the following problems.

Even if the external magnetic field shows an abnormal value (error) due to a disturbance element (e.g. high voltage line, iron motion, gas stunter, etc.), the above magnetic sensor has no means to determine whether the detected value is incorrect. There is a problem in that a signal proportional to the external magnetic field is output as an appropriate value, making it impossible to obtain accurate azimuth data.

From the above, an object of the present invention is to provide an orientation sensor that can determine whether magnetic information is correct or incorrect and can output appropriate orientation data even if the magnetic information is incorrect.

Means for Solving the Problems> FIG. 1 is a block diagram of essential parts of an orientation sensor according to the present invention.

IA, 'B are magnetic sensors, Δθ8. Δθ5 is a signal, 2 is a comparison means, 2 is a comparison result, 3 is a calculation means, 3
al is direction data.

Effect〉 Multiple magnetic sensors IA and IB individually generate signals proportional to the external magnetic field. , Δθ5, and the comparison means 2 outputs each signal Δθ from the plurality of morale sensors IA, IB. , △θ
8 and outputs the comparison result 2a, and the calculation means 3 calculates the orientation data 3a according to the comparison result 2a output from the comparison means 2.

<Embodiment> FIG. 1 is a block diagram of essential parts of a direction sensor showing an embodiment of the present invention.

IA and IB are magnetic sensors, Δθ8. Δθ8 is a signal, 2 is a comparison means, 2a is a comparison result, 3 is a calculation means, and 3a is azimuth data.

Figure 2 shows the signal △θ8. This is a signal value output characteristic diagram of Δθ8. The vertical axis represents the angle of the vehicle's traveling direction (racl), and the horizontal axis represents time t.

The magnetic sensors IA and IB are installed in the car with their installation positions separated from each other, and here, in order to simplify the explanation, two are assumed. The air sensors IA and IBi are set so that Δθ8=Δθ8 in the absence of disturbance elements. Here, the signal Δθ is distorted due to disturbance elements.

If an error occurs in Δθ, the respective signals Δθ8, . Since there is a difference in Δθ, Δθ8
≠△θ, and the relationship Δθ6=Δθ no longer holds true.

Comparison means 2 compares signals Δθ6. output from two magnetic sensors IA and IB. By comparing Δθ8, the two signals Δθ8
．． △θ1. A comparison result 2B indicating that is equal or unequal is output. This allows us to know whether the currently detected magnetic information is correct or incorrect.

The calculation means 3 outputs the comparison result 2a from the comparison means 2.
indicates that Δθ=Δθ5, then the magnetic sensor I
A (or magnetic sensor IB) outputs the signal △θA
(or Δθ,), the orientation data 3a is calculated.

Also, comparison result 3a is Δθ. When indicating that ≠Δf15, the given orientation data 3 is calculated by the arithmetic processing routine described later.
Calculate a.

Next, the first element of the orientation sensor of the present invention will be explained with reference to the third section.

Figure 3: A flowchart of the process of the present invention, 101 to 10
4 (show each step.

First, magnetic sensors IA and IB generate a signal (magnetic information) Δθ proportional to the external magnetic field. , Δθ6 are detected (step 101).

Next, check whether Δθ=Δθ (step 102), Δθ. = Δθ8, then the signal ΔθA(Δθ8
) is calculated according to the direction data 3a (step 103
).

On the other hand, Δθ is checked in step 102. If ≠Δθ6, jump to the calculation processing routine (step 104)
.

4(a) to 4(C) are flowcharts showing an embodiment of the arithmetic processing routine according to the present invention, and 201 to 403 indicate each step.

FIG. 4 (When the arithmetic processing routine in al is activated, the signals Δθ4 and Δθ5 at that time are invalidated at step 201), Δθ. The R& signal of =Δθ8 is used to calculate the orientation data 3a (step 202). Then, the signal ΔθA, Δθ8 that is output after that is Δθ1=Δ
θ, step 203), YES
If so, the process ends.

On the other hand, if Δθ ≠ Δθ8 in step 203, the process returns to step 201.

Fig. 4 (When the arithmetic processing routine in bl is activated, the signal Δθ at that time, Δθ8 is invalidated and step 301), the line of the characteristic diagram where Δθ8 = Δθ8 until then is extended functionally. The resulting signal Δθ. , Δθ8 (of course, Δθ=Δθ8), the orientation data 3a is calculated (step 302). Then, a signal Δθ is output after that. , △θ, is Δθ. -Δθ8 (step 303); if YES, the process ends.

On the other hand, in step 303, Δθ. If ≠Δθ, the process returns to step 301.

When the arithmetic processing routine in FIG. 4(C) is activated, the signal Δθ is used at that time, and Δθ8 is invalidated (Step 401), other sensors (for example, an angular velocity sensor using centrifugal force, a steering wheel turning angle), etc. Direction data 3a is calculated using data from a steering angle sensor (sensing steering angle sensor, etc.) (step 402). Then, a signal Δθ is output after that. .

Check whether Δθ8 is Δθ6=Δθ8 (step 403), and if YES, the process ends.

On the other hand, if Δθ6≠Δθ8 in step 403, the process returns to step 401.

In the above embodiment, the comparison result 2a was explained as a binary value of equality and inequality, but in the case of inequality, it is classified into several stages depending on the magnitude of the error, and a different direction calculation process is performed for each stage. It's okay to run it.

FIG. 5 (al and (bl) are a plan view and a side view showing an example of the installation position of the magnetic sensor.

IA~ID are magnetic sensors, and magnetic sensor IA.

The IB is installed diagonally on the roof of the car, and is equipped with a magnetic sensor IC.
, ID are provided diagonally at the tip of the hood and the rear end of the trunk of the car.

At the same time, magnetic sensors IE, IF, etc. (not shown) are installed at two locations on the roof or at two locations at the front and rear ends of the vehicle as shown in FIG. You may use it.

<Effects of the Invention> According to the present invention, a plurality of magnetic sensors installed apart from each other and a comparison means that compares each signal output from these magnetic sensors and outputs the comparison result are provided. and a calculation means for calculating azimuth data according to the comparison result output from the comparison means, it is possible to judge whether the output signal of the magnetic sensor, which is magnetic information, is correct or not, and whether the signal is incorrect. It has the excellent advantage that appropriate orientation data can be obtained even in the case of

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the main parts of the orientation sensor according to the present invention, and Fig. 2 shows the signal Δθ. , Δθ6 signal value output characteristic diagram, 3rd
Figure 4 is a flowchart of the processing of the present invention; Figure 4 al to (C) are flowcharts showing an embodiment of the arithmetic processing routine of the present invention; Figure 5 fal and (bl are planes showing an example of the installation position of the magnetic sensor). They are diagrams and side views. LA, IB...Magnetic sensor, Δθ, Δθ8...Signal, 2...Comparison means, 2a...Comparison result, 3...Calculation means, 3a...Direction data Patent applicant Albain Chiki Saito, Agent, Patent Attorney, Co., Ltd. Figure 1 ΔθA Figure 2 υ Figure 3 Figure 5 (a) (b)

Claims (1)

[Claims] It has a magnetic sensor that outputs a signal proportional to the external magnetic field,
In the azimuth sensor that outputs azimuth data in response to signals output from the magnetic sensor, a plurality of magnetic sensors installed at separate installation positions are compared with each signal output from these magnetic sensors. What is claimed is: 1. A direction sensor comprising: a comparison means for outputting a comparison result based on the comparison result; and a calculation means for calculating direction data according to the comparison result output from the comparison means.