JPH05133751A - Gyrocompass - Google Patents

Abstract

PURPOSE:To enhance the measuring accuracy by calculating the rolling wheel ball azimuth signal and its rate of change, reckoning the velocity signal given by a speed sensor and the rate of change of the velocity signal, and computing the horizontal acceleration and velocity error from the lattitude signal given by a lattitude sensor, and thereupon correcting the azimuth signal with the error amount. CONSTITUTION:A rolling wheel ball azimuth signal 25 is given to an azimuth transmission part 1 from a master compass 2. Besides, the transmission part 1 is fed with a velocity signal 3S from a speed sensor 3 and a lattitude signal 4S from a lattitude sensor 4. Then the velocity error amount and horizontal acceleration are calculated from the rolling wheel ball azimuth signal 2S and its rate of change, the velocity signal 3S and its rate of change, and the lattitude signal 4S, and upon correcting the gyrocompass azimuth signal with the calculated error amount, the rolling wheel ball azimuth signal having undergone necessary correction is passed to external appliance as the gyrocompass azimuth signal 1S. Thus the horizontal acceleration error, which is a problem when the pendulum system is adopted, can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pendulum type gyro compass.

[0002]

2. Description of the Related Art Conventionally, a pendulum type gyro compass (hereinafter simply referred to as a gyro compass) as this type of technique.
Is configured in a state equivalent to a state in which a weight is attached below a gyroscope (which is generally called a rolling ball and is hereinafter referred to as a rolling ball), and thereby a finger north force is obtained (for example, a compass and a gyro). Theory and practice (Shigei and Kobayashi;
"Kaibundou", issued P124-157,).

[0003]

The above-mentioned conventional technique has the following problems.

(A) In principle, an error occurs when an acceleration other than the gravitational acceleration acts.

(B) Normally, the gyro compass is applied to a ship. In this ship, the horizontal acceleration is a problem because both the movement amount and the working time are small in the vertical acceleration. As a means for preventing the occurrence of azimuth error due to horizontal acceleration, it is common practice to adjust the cycle of finger north movement of the rolling ball to the cycle of the Schuler (84.4 minutes). However, even with a gyro compass adjusted to the period of the Schuler, an acceleration error occurs at latitudes other than the latitude set to have the period of the Schuler.

The present invention has been made in view of the above conventional problems, and an object thereof is to include a signal output from the master compass depending on conditions when horizontal acceleration acts. A gyro compass configured to improve the accuracy of a signal output from the master compass by removing the velocity error and horizontal acceleration error components.

[0007]

To achieve the above object, the present invention incorporates a pendulum type rolling ball, detects the direction of the rolling ball, and outputs a rolling ball direction signal 2S. A master compass 2 for outputting, a speed detector 3 for outputting a speed signal 3S, a latitude detector 4 for outputting a latitude signal 4S,
By inputting the rolling wheel azimuth signal, the speed signal and the latitude signal, a speed error amount and a horizontal acceleration amount are obtained from the rolling ball azimuth signal and its change rate, the speed signal and its change rate and the latitude signal. And an azimuth transmitting section 1 for correcting the wheel-turning ball bearing signal with the calculated error amount and outputting the corrected wheel-turning ball bearing signal as a gyrocompass bearing signal 1S. Is.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing specific embodiments.

FIG. 1 is a diagram showing a specific embodiment of the gyro compass of the present invention. FIG. 2 is a flow chart used to explain FIG.

In FIG. 1, the basic configuration of the gyro compass of the present invention is such that, when 1 is an azimuth transmitting unit and 2 is a master compass, a master wheel compass 2 outputs a rolling wheel azimuth signal (master compass 2 is a pendulum type). The built-in configured rolling ball is detected, and the bearing of this rolling ball is detected, and this is output as a bearing signal. 2S is sent to an external device (not shown) such as a repeater compass or an autopilot. Azimuth transmitter 1 that transmits and outputs signal 1S
Output to.

At this time, the azimuth transmitting unit 1 receives the speed signal 3S from the speed detector 3 which is constituted by, for example, an electromagnetic log, in addition to the above-mentioned rolling wheel azimuth signal 2S.
The latitude signal 4S is input from the latitude detector 4 which uses a device such as an obalPositioning System. Then, horizontal acceleration error correction and speed error correction are performed on the rolling wheel azimuth signal 2S (that is, from the rolling ball position signal 2S and its change rate, the speed signal 3S and its change rate, and the latitude signal 4S, the speed error amount is calculated. Then, the horizontal acceleration amount is calculated, and the gyro direction signal is corrected by the calculated error amount), and then the corrected rolling ball direction signal is output as a gyro compass direction signal 1S to an external device (not shown).

The operation and function of such a configuration are as follows. This will be described with reference to the flowchart of FIG.

The gyro compass is roughly classified into the Anschutz system and the Sperry system, but since there is no difference in the mechanism for correcting the horizontal acceleration error, the pendulum gyro compass of the Anschutz system will be described here.

The equation of motion of the rolling balls of the pendulum type gyro compass of the Anschutz system is as follows.

(D / dt) α = [− {mgaβ + Cγ + ma (d / dt) V _N } / H] + ωsin ψ + (V _E / R) tan ψ (1)

(D / dt) β = ωcosψ · sinα + (V _N / R) (2)

(D / dt) γ = −f [β + γ + tan ⁻¹ {(d / dt) V _N } / R] (3)

Where α is the azimuth angle of the rolling sphere, β is the north-south inclination angle of the rolling sphere (this β is a few degrees at maximum and can be regarded as a minute angle), γ is the north-south oil of the damping oil. Plane inclination angle, m: Rolling ball mass, g: Gravitational acceleration, a: Distance between buoyancy and center of gravity of the rolling ball, C: North-south torque constant of damping oil, ω: Earth rotation angular velocity, ψ; Gyro latitude location compass is present, R; earth radius, H; angular momentum rolling wheels sphere has, V _N;
V _{E in} the north-south direction of the navigation body equipped with the gyro compass, V _E ; Velocity component in the east-west direction of the navigation body equipped with the gyro compass, (d / dt) V _N ; North-south direction of the navigation body equipped with the gyro compass The velocity component.

By the way, in the state where the acceleration other than the gravitational acceleration does not act and the navigation body has no velocity, the wheeled ball stops the north movement of the finger 5 hours after the activation and faces the true north direction.

When the navigation body has a velocity, the terms V _E and V _N become significant in the equations (1) and (2), and a velocity error occurs. Further, if the navigation body has a horizontal acceleration, the term of (d / dt) V _N becomes significant in the equations (1) and (3), and a horizontal acceleration error occurs.

The amount of this horizontal acceleration error is a maximum of 2 when changing the speed from 0 knots (or southward) speed to 20 knots or by changing the north (or south) speed of 20 knots by 180 degrees / 2 minutes. The amount is about 3 degrees (however, the speed error is excluded).

The correction operation of the horizontal acceleration error will be described in detail below.

At the time of activating the gyro compass, the horizontal acceleration error correcting operation is stopped until the direction of the rolling sphere is settled.

When the horizontal acceleration error correction is not in operation, the azimuth transmitting unit 1 calculates whether α = V · cos θ / 5π · cos ψ (4) (regardless of static or non-static). , Θ; navigation direction, V; navigation speed in θ direction, 5
The speed error amount is obtained by the method shown in (π; constant), and the wheel-ball direction is corrected by the speed error amount (for details of the speed error correction calculation, see, for example, Japanese Patent Laid-Open No. 61-145411, "Gyro Compass for Ships". Since it is a generally known technique as already disclosed in ", etc., detailed description thereof will be omitted), and is output as a gyro compass direction.

After the direction of the rolling ball is settled, the monitoring of the speed value and the direction of the rolling ball is started at regular intervals. The monitoring value is held while being sequentially updated for a specified time, and the rate of change and the amount of change in the speed and the rolling ball azimuth during that time are evaluated each time the data is updated.

The speed is also evaluated in terms of the direction of the rolling wheels. This is heading E (east) or W (west)
This is because (d / dt) V _N = 0.

If the evaluation result matches the specified amount, the horizontal acceleration error correction operation is started.

The amount of horizontal acceleration acting on the rolling ball is calculated from the held data.

From the wheel sphere direction, speed and latitude value, α,
Determine the values of β and γ before the horizontal acceleration acts.

From the amount of horizontal acceleration, the values determined by the changes in α, β and γ while the horizontal acceleration is acting are obtained by numerical integration as initial values, and the value α ₀ immediately after the action of the horizontal acceleration is finished, Determine β ₀ and γ ₀ .

The gyro compass bearing signal 2S from the master compass 2 is corrected with a value of α ₀ , and this is regarded as the true north bearing, and is output to the external device as a gyro compass bearing signal 1S. The velocity error component of this signal is also corrected (the velocity error component is also included in the equation of motion).

Even after the horizontal acceleration error correction operation is started, the monitoring of the speed value and the wheel ball bearing value is continued. After the start of the horizontal acceleration error correction operation, if the speed or the rate of change of the rolling ball azimuth exceeds the specified amount, the horizontal acceleration error correction operation is stopped.

After the correction operation for the specified time is stopped, the routine returns to the routine for determining the start of the horizontal acceleration error correction operation.

After the horizontal acceleration error correction operation is started, α ₀ ,
Using β ₀ and γ ₀ as initial values, changes in the values of α, β, and γ are sequentially obtained in real time by numerical integration (calculation of horizontal acceleration error correction amount). The gyro compass bearing signal 2S from the master compass 2 is corrected by the value of α and output to the external device as a gyro compass bearing signal 1S. However, since the rate of change of the value of the error amount α is small (cycle of about 84 minutes), the calculation of the values of α, β, and γ can be made longer than that of the rolling wheel azimuth signal output cycle.

The correction of the rolling-ball direction signal when the values of α, β, and γ are not calculated is performed by using the value of α calculated immediately before.

After the start of the horizontal acceleration error correction operation, the correction operation is stopped when a specified time has elapsed, and the routine returns to the routine for determining the start of the horizontal acceleration error correction operation.

[0037]

Since the present invention is constructed as described above, it has the following effects. (B) The horizontal acceleration error, which is a problem due to the pendulum method, can be corrected without using an expensive device such as a servo system using an accelerometer.

[Brief description of drawings]

FIG. 1 is a diagram showing a specific example of a gyro compass of the present invention.

FIG. 2 is a flow chart used for the explanation of FIG.

[Explanation of symbols]

 1 Direction Transmitter 2 Master Compass 3 Speed Detector 4 Latitude Detector

Claims (1)

[Claims] 1. A master compass 2 which incorporates a pendulum type gyroscope to detect a direction of the gyroscope and outputs a gyro direction signal 2S, a speed detector 3 which outputs a speed signal 3S, and a latitude. A latitude detector 4 that outputs a signal 4S and the gyro azimuth signal, the speed signal, and the latitude signal are input, and the gyro azimuth signal and its change rate, the speed signal and its change rate, and the speed from the latitude signal are input. An error amount and a horizontal acceleration amount are calculated, the gyro azimuth signal is corrected by the calculated error amount, and the corrected gyro azimuth signal is used as the gyro compass azimuth signal 1S.
A gyro compass characterized by comprising an azimuth transmitting unit 1 for outputting as.