RU2153152C1 - Method of correction of gyroscopic compass - Google Patents

Abstract

FIELD: navigational instrumentation, determination and compensation for latitude error of two-mode single- gyroscope course indicators-gyroscopic compasses. SUBSTANCE: after spinning of gyroscope and its holding for the course of time necessary to achieve steady-state thermal and electrical condition platform is so turned around vertical axis that horizontal sensitivity axis of gyroscopic compass is directed to north. Mode of gyroazimuth is set. Current realizing maximum spin rate of platform in azimuth is supplied to horizontal torque generator. Current in vertical torque generator proportional to angular spin rate of platform around horizontal axis is measured. Current of initial value but of opposite sign realizing opposite angular spin rate of platform in azimuth is supplied to horizontal torque generator. Current in vertical torque generator proportional to new angular spin rate of platform around horizontal axis is measured in vertical torque generator. Correction is computed and error compensation current is supplied to vertical torque generator. EFFECT: increased precision of gyroscopic compass thanks to compensation for latitude error. 1 dwg

Description

 The invention relates to the field of navigation instrumentation and can be used to determine and compensate for the latitudinal error of two-mode single-gyro direction indicators - gyro compasses (GK).

 The aim of the invention is to improve the accuracy of determining and compensating for the latitudinal error of the dual-mode gyro course indicator.

 There is a known method of correcting HA, which consists in starting the HA, holding it for the time necessary to achieve a stable thermal and electric state, comparing the HA course with the true stand rate or obtained, for example, direction finding of a known landmark; the formation of an amendment equal to the difference in rates and adding it to the exit rate of the Civil Code [1].

где φ - широта места,
P - восточный дрейф ГК,
U - скорость вращения Земли,
ΔC - ошибка съема,
Δtgφ - широтная погрешность,
При изменении широты с северной на южную возникает дополнительная погрешность ΔKg гирокомпаса, равная удвоенной первоначальной широтной погрешности:

где

погрешность гирокомпаса при φ_ю ,
φ_c - северная широта,
φ_ю - южная широта,
φ_o - абсолютное значение широты места.The disadvantage of this method is the occurrence of additional errors associated, for example, with a change in the latitude of the place of navigation. The error of the gyrocompass ΔK in determining the true course can be represented by the formula

where φ is the latitude of the place,
P is the eastern drift of the GK,
U is the speed of rotation of the Earth,
ΔC - removal error,
Δtgφ - latitudinal error,
When changing latitude from north to south, an additional error ΔKg of the gyrocompass arises, equal to twice the original latitudinal error:

Where

gyrocompass error in φ _th,
φ _c - north latitude,
φ _Yu - south latitude,
φ _o - the absolute value of the latitude of the place.

In existing GCs such as GKU-1, GKU-2, GYUYS, the deviation of the horizontal axis of sensitivity can reach 10 ^o -15 ^o , which gives rise to an additional course error, ΔK _g = (0.3 ^° -0.5 ^° ) • tgφ _o , those. at moderate latitude 45 ^o additional error will be 0.3 ^o -0.5 ^o .

 The aim of the invention is to increase the accuracy of the HA by identifying and compensating for latitudinal error.

где Ω_r1 - угловая скорость платформы вокруг горизонтальной оси,
Ω_r2 - новая угловая скорость платформы вокруг горизонтальной оси,
Ω_B - угловая скорость платформы в азимуте,
вычисляют компенсационную поправку в виде тока по формуле

где K_gm - передаточный коэффициент датчика момента по току,
H - кинетический момент,
подают ток I_k на вертикальный датчик момента ГК.This goal is achieved by the fact that after starting the HA and holding it for the time necessary to achieve a steady thermal and electrical state, deploy the HA platform around the vertical axis so that the horizontal axis of the sensitivity of the HA is directed to the north, then turn on the gyro azimuth mode, serves a horizontal gyro unit torque sensor current, which realizes the maximum rotation speed of the GC platform in azimuth, measures the current in a vertical torque sensor proportional to the angular velocity of eniya HA platform about a horizontal axis Ω _r1, fed to a horizontal torque sensor initial current, but opposite sign, which implements the opposite angular velocity in azimuth
+ Ω _B2 = -Ω _B1 = Ω _B ,
measure the current in the vertical moment sensor, proportional to the new angular velocity of the GC platform rotation around the horizontal axis Ω _r2 , calculate the non-alignment (deviation) Δ by the formula

where Ω _r1 is the angular velocity of the platform around the horizontal axis,
Ω _r2 is the new angular velocity of the platform around the horizontal axis,
Ω _B is the angular velocity of the platform in azimuth,
calculate the compensation correction in the form of current according to the formula

where K _gm - gear ratio of the torque sensor current,
H is the kinetic moment,
supply current I _k to the vertical torque sensor GK.

The theoretical rationale for the proposed method is as follows. In the gyro azimuth mode, the current in the vertical moment sensor is proportional to the angular velocity of the HA platform around the horizontal axis:
Ω _r = U • cosφ • sink + P + Ω _B • Δ (5),
where Ω _B is the angular velocity of the HA platform in azimuth,
k is the course value.

Установка платформы ГК на румб 90^o осуществляется либо вручную, либо подачей большого тока в горизонтальный датчик момента ГК, либо подачей слабого сигнала в усилитель азимутальной следящей ГК. Для определения поправки с точностью 0,005^o/ч достаточно установить платформу на север с погрешностью 1-2^o.By asking different movements in azimuth on the course k = 90 ^o and measuring currents in a vertical moment sensor or the angular velocity of the platform around a horizontal axis, we obtain two equations:
Ω _r1 = U • cosφ + P + Ω _B • Δ (6),
Ω _r2 = U • cosφ + P-Ω _V • Δ (7),
of which the value of the non-exhibition is found:

The GC platform is installed on the 90 ^° rumb either manually or by applying a large current to the horizontal GC moment sensor, or by supplying a weak signal to the azimuthal tracking GC amplifier. To determine the correction with an accuracy of 0.005 ^o / h, it is enough to set the platform to the north with an error of 1-2 ^o .

 The operations of the method associated with the determination of the failure are implemented by the instructions for adjusting and calibrating the HA at its manufacture, and the correction operation is implemented in the HA design by applying an additional current component proportional to the latitudinal correction to the vertical sensor.

 The proposed method can be implemented, for example, in the construction of a gyrocompass, the structure of which is presented in the drawing by a block diagram.

The gyrocompass contains:
- platform 1
- gyroscope 2
- vertical and horizontal torque sensors 3, 4
- angle sensor 5
- electronic unit 6
- operator console 7
- accelerometer 8.

 KG works as follows. The gyrocompass holds the platform 1 in the north direction thanks to the currents supplied to the horizontal 3 and vertical 4 torque sensors generated in the electronic unit 6 by the signal of the accelerometer 8. The latitude error component that compensates for the latitudinal error in the horizontal moment sensor is formed in the electronic unit 6 by the non-alignment signals Δ and the latitude of the place φ entering the operator console 7.

Sourse of information
1. Kogan V. I., Chichinadze M. V. Ship's gyroazimuth compass "Vega". M: Transport, 1983, p. 87, p. 100.

Claims (1)

A method for correcting a gyrocompass, including starting the gyrocompass, holding it for the time necessary to achieve a steady thermal and electric state, characterized in that, in addition to reaching a steady thermal and electric state, the gyrocompass platform is rotated around a vertical axis so that the horizontal axis of the gyrocompass sensitivity is directed to the north, turns on the gyro azimuth mode, a current is applied to the horizontal torque sensor, which implements the maximum angular orost azimuth rotation of the platform, the current is measured in the vertical sensor torque proportional to the angular rate gyro platform rotation about a horizontal axis, is fed into a horizontal torque current sensor initial value, but opposite sign, which implements the opposite angular rotation of the platform in azimuth rate + Ω _B2 = -Ω _B1 = Ω _B , measure the current in a vertical torque sensor proportional to the new angular velocity of rotation of the gyrocompass platform around the horizontal axis, calculate the correction by the formula

where Ωr ₁ is the angular velocity of the platform around the horizontal axis;
Ωr ₂ - the new angular velocity of the platform around the horizontal axis,
Ω _B is the angular velocity of the platform in azimuth,
form a compensation correction in the form of current according to the formula

where K _dm - gear ratio of the torque sensor current;
H is the kinetic moment;
U Earth rotation speed;
φ is the latitude of the place,
and a current I _{k is} supplied to a vertical gyrocompass moment sensor.