JP2000121364A - Azimuth indicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable one angular velocity sensor to measure the absolute azimuth and azimuth changes in the moving direction during the movement. SOLUTION: An attitude converting means which converts the attitude of the angular velocity sensor 4 is composed of a support shaft 2 which projects at 35 deg. from the plate surface of a substrate 1, and a rotary support body which supports the angular velocity sensor 4 so that an input shaft 5 crosses the support shaft 2 at 55 deg. from the core of the support shaft 2. Here, the attitude converting means converts the direction of the input shaft of the angular velocity sensor 4 to a Z, an X, and a Y direction to measure the angular velocities at the respective attitude positions, thereby measuring the absolute azimuth in a stationary state and azimuth changes in the moving direction during the movement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an azimuth meter configured to measure an absolute azimuth (angle from north) with one angular velocity sensor.

[0002]

2. Description of the Related Art In the past, a magnetic compass has been used for finding an absolute azimuth (north azimuth), and in recent years, a mechanical top gyro compass has been used. A magnetic compass is susceptible to the influence of the surrounding magnetism, and a top gyro compass is disadvantageous in that it is expensive and a long time is required from when the power is turned on to when it can be used.

Recently, for example, one angular velocity sensor such as an optical fiber gyro is used, and its input shaft is oriented horizontally.
An azimuth meter that makes one rotation about a vertical axis and obtains the north from the distribution of the rotational angular velocity of the earth on a horizontal plane has been considered.

[0004]

The azimuth meter using the above-mentioned optical fiber gyro has a drawback that the azimuth cannot be measured unless it is stationary during the measurement. To measure azimuth while moving, in addition to the first angular velocity sensor, a second angular velocity sensor whose input axis is oriented vertically is installed, and the azimuth change rate during movement is measured by the second angular velocity sensor. There is also a measurement method of measuring and integrating, and adding the azimuth obtained at the time of rest as an initial value to the integrated value to know the azimuth while moving.

However, according to this measuring method, there is a disadvantage that two angular velocity sensors are required and the cost is high. As a method of knowing the azimuth during movement using one angular velocity sensor, for example, when stationary, the input axis of the gyro is turned in the horizontal direction, and this is rotated around the vertical axis. There is also a method of arranging the shaft in the vertical direction.

However, in order to adopt this method, it is necessary to change the attitude of the angular velocity sensor in two directions. Therefore, the structure of the attitude changing mechanism becomes complicated, and the attitude changing mechanism alone becomes expensive. An object of the present invention is to change the input axis of one angular velocity sensor between a horizontal direction and a vertical direction by a posture rotation mechanism having only one axis rotation mechanism, to measure the absolute azimuth when stationary, and to reduce the azimuth change rate during movement. It is intended to propose an azimuth meter capable of calculating and integrating the obtained values, and adding the integrated value to the absolute direction obtained at the time of standstill to output an instantaneous azimuth.

[0007]

According to the present invention, there is provided a substrate supported in a horizontal position, and an input shaft. When a rotation input is given about the input shaft, angular velocity data corresponding to the input angular velocity is output. And an angular velocity sensor supporting the angular velocity sensor such that the input shaft is oriented in the vertical direction Z with respect to the plate surface of the substrate and in two horizontal directions X and Y perpendicular to each other in a horizontal plane parallel to the substrate. The attitude conversion means and the attitude conversion means change the input axis of the angular velocity sensor to a position facing the vertical direction Z and subtract the theoretical value of the vertical component of the earth rotation angular velocity from the angular velocity data measured to calculate the bias error of the angular velocity sensor. A bias error is calculated from a bias error calculating means and two earth rotation angular velocities measured with the input axis of the angular velocity sensor changed in the X direction and the Y direction. Then, the compass is determined by earth rotation speed calculating means for obtaining a correct earth rotation angular velocity component, and azimuth calculating means for calculating an azimuth determined on the substrate from the X, Y direction earth rotation angular velocity components calculated by the earth rotation angular velocity calculation means. It is composed.

[0008] A feature of the present invention resides in the posture changing means. That is, a support shaft that protrudes and supports the posture changing means from the substrate in a posture inclined by about 35 ° from the plate surface of the substrate, and is rotatably supported by the support shaft, and the input shaft is inclined by about 55 ° from the axis of the support shaft. And a rotary support that supports the angular velocity sensor in a different posture. The above-mentioned about 35 ° is exactly Sin ^-1 (1 / √3), and about 55 ° is a value obtained by subtracting the above from 90 °.

According to this structure, the input shaft of the angular velocity sensor is moved during the movement only by rotating the rotary support about the support shaft.
It can be moved along a conical surface that intersects at an angle of 5 °, and can be switched between a vertical Z direction and X and Y directions that are orthogonal to each other in a horizontal plane parallel to the plate surface of the substrate.

[0010] Therefore, since the attitude changing means can be simply constructed, there is an advantage that the compass can be manufactured at low cost. Further, the attitude of the angular velocity sensor can be easily changed because the attitude of the angular velocity sensor can be changed by rotating the rotary supporter supported by the uniaxial rotation support mechanism. As a result, when the input axis of the angular velocity sensor is oriented in the vertical Z direction, the bias error of the angular velocity meter is estimated by subtracting the vertical component theoretical value of the earth rotation rate from the angular velocity data measured by the angular velocity sensor, and the input axis of the angular velocity sensor is estimated. After correcting the bias error from two earth rotation rate data measured in the X direction and the Y direction, arithmetic processing can be performed to obtain an absolute azimuth (angle from north).

At the time of rest, the absolute azimuth is measured. During the movement, the input axis of the angular velocity sensor is oriented in the vertical Z direction, and the azimuth change rate during the movement is measured and integrated with the initial azimuth, so that the azimuth change in the movement direction every moment can be calculated. Therefore, according to the compass of the present invention, one angular velocity sensor is supported by the one-axis support mechanism, and the attitude of the input axis of the angular velocity sensor is set in the Z direction and X direction.
Since the direction is changed into three directions, ie, the direction and the Y direction, the structure of the supporting mechanism is simple and can be manufactured at low cost.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a conceptual diagram of a supporting mechanism of an gyro which is a main part of the present invention. In the figure, reference numeral 1 denotes a substrate.
The substrate 1 is supported in a horizontal position, and is mounted on, for example, a vehicle. 1A indicates the traveling direction of the device, that is, the front. Alternatively, a support shaft implanted at 35 ° to the substrate 1 is shown. That is,
In this embodiment, a case is shown in which a rotary support 3 is rotatably mounted on a support shaft 2 and an input shaft 5 of an angular velocity sensor 4 is supported on the rotary support 3 at an angle of 55 ° from the support shaft 2.

According to this configuration, the rotary support 3 is connected to the support shaft 2.
, The input shaft 5 of the angular velocity sensor 4 can be changed to a posture oriented in the vertical Z, X, and Y directions with respect to the plate surface of the substrate 1. In other words, the support shaft 2 is supported at an angle of 35 ° from the plate surface of the substrate 1, and the rotary support 3 supports the input shaft 5 of the angular velocity sensor 4 at an angle of 55 ° from the support shaft 2; ° = 90 °, and can be turned in the Z direction. Furthermore, the rotating support 3
Is rotated, the input shaft 5 of the angular velocity sensor 4 is
Along the conical surface 6 (see FIG. 2) which intersects with the axis at 55 °. During this movement, the input shaft 5 of the angular velocity sensor 4 passes through two positions parallel to the plate surface of the substrate 1. At these two locations, the input shaft 5 of the angular velocity sensor 4 is oriented in the X and Y directions, which are orthogonal to each other. still,
In order to make the illustrated X direction coincide with the traveling direction 1A of the apparatus, the support shaft 2 may be set at a position rotated 45 ° clockwise from the traveling direction 1A of the apparatus when viewed from above.

The posture in each of the directions of Z, X and Y is, for example, Z
It can be defined that the rotation support 3 is stopped at intervals of 120 ° based on the direction. Thus, for example, the rotating support 3
Is rotated by a pulse motor or the like, and the stop position is defined at every 120 °, whereby the direction of the input shaft 5 of the angular velocity sensor 4 can be set to the posture position in each of the Z, X, and Y directions.

In the above description, the support shaft 2 is planted on the substrate 1 and the rotary support 3 is rotatably supported on the support shaft 2. Alternatively, it is also possible to adopt a structure in which the supporting shaft 2 and the rotating support 3 are integrally rotated. Whichever structure is adopted, the rotary support 3 can be set to any posture in each of the Z, X, and Y directions by using a drive source such as a pulse motor.

In addition to the pulse motor, for example, a structure in which an optical position detection sensor is disposed at each position in each of the Z, X, and Y directions, and the stop signal of the motor is controlled by the detection signal is also conceivable. FIG. 3 shows the state of the entire apparatus. Substrate 1
A driving source 7 such as a pulse motor is mounted on the rotary support 3, and the rotary support 3 is rotationally driven by the driving source 7.
Is changed to each of the Z, X, and Y directions. The angular velocity generated by the geographic rotation at each turning position is measured, and the measurement result is input to the arithmetic unit 8. The arithmetic unit 8 calculates the absolute azimuth when stationary and outputs the absolute azimuth, while supporting the input shaft 5 of the angular velocity sensor 4 in the Z direction during the movement, measures the azimuth change rate during the movement and integrates it with the initial azimuth. Then, the azimuth change every moment can be calculated.

The arithmetic unit 8 can be constituted by, for example, a microcomputer, and can execute the calculation of the absolute azimuth at rest, the integration operation during movement, the control of the drive source 7, and the like. Hereinafter, an example of a procedure for calculating the absolute azimuth in the arithmetic unit 8 will be described. (1) Orient the substrate 1 horizontally and in the direction in which the traveling direction 1A is to be measured.

(2) The direction of the input shaft 5 of the angular velocity sensor 4 is set in the Z direction in accordance with a command from the arithmetic unit 8, and the output ωZ 'of the angular velocity sensor 4 is read. (3) The direction of the input shaft 5 of the angular velocity sensor 4 is set in the X direction according to a command from the arithmetic unit 8, and the output ω of the angular velocity sensor 4 is set.
Read X '. (4) The input shaft 5 of the angular velocity sensor 4 is set in the Y direction according to a command from the calculation unit 8, and the output ωY ′ of the angular velocity sensor 4 is set.
Read.

(5) The vertical component Ωv of the earth rotation rate is calculated from the latitude of the area. Ωv = Ω * cos (latitude) Ω: Earth rotation rate 1
5 (° / H) (6) The bias error δω of the rate sensor is obtained by subtracting Ωv from ωZ ′.

Δω = ωa′−ΩV (7) By subtracting the bias error δω of the angular velocity sensor 4 obtained in (6) from ωX ′ and ωY ′, the correct earth rotation rate components ωX and ωY can be obtained. ωX = ωX′−δω ωY = ωY′−δω (8) ωX is the rate of the forward axis on the horizontal plane, and ωY is the rate of the right axis on the horizontal plane. From these two, the direction ψo of the device is calculated by the following equation.

Ψo = arctan (ωY / ωX) (9) When moving, the input shaft 5 of the angular velocity sensor 4 is set in the Z direction, and the azimuth ψo obtained in (8) is set as an initial value, and the instantaneous rate is set. By integrating the sensor output ωX '(t),
Outputs azimuth リ ア ル タ イ ム in real time while moving. ψ = ∫ (ωZ ′ (t) −δω) dt + ψo (10) When the vehicle comes to rest, steps (1) to (8) are performed again.

In the above description, the substrate is placed horizontally.
If a tilt sensor is installed on the X and Y axes on the substrate, it can be corrected even if there is some tilt.

[0023]

As described above, according to the compass of the present invention, since the attitude changing means for changing the attitude of the angular velocity sensor 4 is constituted by a one-axis rotating mechanism, the attitude changing means can be manufactured at low cost. Can be. The absolute azimuth can be measured while still, and the azimuth can be output in real time from the measurement of the azimuth change rate while moving. Furthermore, even if a low-precision angular velocity sensor is used, the bias error of the angular velocity sensor 4 can be measured and corrected for each stop, so that it can be corrected.
The advantage that the absolute azimuth can be measured with a small size, at low cost, and with high accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a configuration of a main part of the present invention.

FIG. 2 is a schematic diagram for explaining an operation of a main part of the present invention.

FIG. 3 is a block diagram for explaining the whole of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Support shaft 3 Rotation support 4 Angular velocity sensor 5 Input shaft 6 Conical surface 7 Drive source 8 Operation part

Claims (3)

[Claims] An angular velocity which has A, a substrate supported in a horizontal posture, and B, an input shaft, and which outputs angular velocity data corresponding to the input angular velocity when a rotation input is given about the input axis. C, the angular velocity sensor, the posture in which the input axis is oriented in the Z direction perpendicular to the plate surface of the substrate, and the two horizontal X, Y directions orthogonal to each other in a horizontal plane parallel to the substrate. D. a vertical component theoretical value of the earth rotation angular velocity from angular velocity data measured in a state where the input means of the angular velocity sensor is supported at a position facing the vertical direction Z; E. a bias error calculating means for calculating a bias error of the angular velocity sensor; and E, two earth measuring points measured with the input axis of the angular velocity sensor supported in the X and Y directions. Subtracting the bias error from the angular velocity, and earth rotation angular velocity calculating means for calculating a correct earth rotation angular velocity component, F, the X calculated in this earth rotation angular velocity calculating means, Y
Azimuth calculating means for calculating an azimuth determined on the substrate from the rotation angle velocity component of the earth in the direction. 2. The angular velocity sensor according to claim 1, wherein said attitude changing means is rotatably supported by a support shaft projecting from the plate surface of said substrate at an angle of 35 ° and said support shaft. Of the input shaft is 55 ° with the axis of the support shaft.
And a rotating support that rotates along a conical surface intersecting at an angle. 3. The azimuth meter according to claim 1, wherein in a state in which the substrate is moved, the input shaft of the angular velocity sensor is supported in the vertical direction Z by the posture changing means, and the azimuth φ0 calculated at rest is an initial value. And a azimuth meter configured to integrate a momentarily measured value of the angular velocity sensor, add the integrated value to the initial value, and output a direction that changes during movement.