RU2187074C1 - Method of correction of gyrocompass - Google Patents

Abstract

FIELD: navigational instrumentation engineering; determination and compensation of gyrocompass errors. SUBSTANCE: method includes starting the gyrocompass and holding it in this mode during definite period of time, comparison of gyrocompass course with true course of stand, forming correction for difference in course and shift of departure course by magnitude of error. Prior to starting the gyrocompass, its platform is turned around vertical axis with gyrocompass sensitivity axis directed to North. Then, directional gyro mode is switched on and current in vertical torque generator is measured. Gyrocompass platform is turned again around vertical axis with gyrocompass sensitivity axis directed to South. Gyro directional mode is switched on again procedure of measuring current in vertical torque generator is repeated. Current Ω_g1 and Ω_g2 in vertical torque generator are proportional to angular velocities of control of gyrocompass around horizontal axis. Drift eastern is calculated according to the following formula: P = 0,5(Ω_g1+Ω_g2). Current compensation error is found according to the following formula: I_P = -PH/K_m.m, where K_m.m. (g.cm/A) is current transfer coefficient of torque generator and H (g. cm. s) is moment of momentum of gyroscope. Current I_P is fed to vertical torque generator of gyroscope. EFFECT: enhanced accuracy of gyrocompass. 12 dwg

Description

 The method relates to the field of navigational instrumentation and can be used to determine and compensate for the basic errors of dual-mode single-gyro direction indicators - gyro compasses (GK).

 A known method for correcting HA is to start 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, by direction finding of a known reference point, forming an amendment equal to the course difference, and adding it to the GK exit rate [see Kogan V.M., Chichinadze M.V. Ship gyroazimutcompass "Vega". M .: Transport, 1983, p. 87, 100].

 The disadvantage of this method is the occurrence of additional errors when changing the latitude of the place of navigation.

где U - скорость Земли,
φ - широта места.As you know, the error of the GK ΔK in determining the true rate depends on its main sources: drift around the eastern axis P and non-alignment Δ in accordance with the expression:

where U is the speed of the Earth,
φ is the latitude of the place.

) в заарретированном нулевом положении, когда сигнал с курсового датчика угла, измеряющего угол поворота между корпусом 3 и платформой 1, равен нулю. Заарретированное нулевое положение получают при регулировке, механически связывая платформу и корпус ГК и выставляя сигнал курсового датчика угла в ноль.The non-exhibition Δ in accordance with figure 1 is the angle between the transverse axis of the body of the body X X _P and the sensitivity axis of the gyroscope X (the X axis is perpendicular to the kinetic moment of the gyroscope

) in a caged zero position, when the signal from the directional angle sensor measuring the angle of rotation between the housing 3 and the platform 1 is zero. Caged zero position is obtained when adjusting, mechanically linking the platform and the main body of the Civil Code and setting the signal of the directional angle sensor to zero.

, определенная при регулировке и зависящая от широты места регулировки φ_ст и поэтому обуславливающая дополнительную погрешность определения курса, которая имеет вид:

Величина (secφ-secφ_ст) для объектов, плавающих в широтах ±70^o, может достигать 1 и значение дополнительной погрешности при реальных для современных компасов дрейфах P=0,1÷0,2[^o/ч] может достигать нескольких градусов.When using the prototype method, a constant amendment is added to the course

, determined during the adjustment and depending on the latitude of the place of adjustment φ _st and therefore causing an additional error in determining the course, which has the form:

The value (secφ-secφ _ст ) for objects floating in latitudes of ± 70 ^o can reach 1 and the value of the additional error for drifts real for modern compasses P = 0.1 ÷ 0.2 [ ^o / h] can reach several degrees.

Величина

для указанных районов плавания может достигать значения 2 и значение дополнительной погрешности при реальных для современных компасов значениях невыставок Δ=0,5^o÷1,5^o может достигать нескольких градусов.In the case where ΔK correction _item is converted to a drift of the formula P _v = ΔK • Ucosφ _{art CT} = P + ΔUcosφ _art and added to the control signal of the gyroscope east velocity around the axis, an additional gyro error will have the form

Value

for these areas of navigation can reach a value of 2 and the value of the additional error at real for modern compasses values of non-adjustments Δ = 0.5 ^o ÷ 1.5 ^o can reach several degrees.

 The first of these methods is used for adjustment at the manufacturer, the second - at the facilities during operation, with a significant change in the correction due to changes in drift R. As shown above, the lack of compensation at the factory with a practically unchanged value Δ does not allow increasing the accuracy neither in the case of applying the first, nor in the case of applying the second method.

 The aim of the invention is to increase the accuracy of the HA by identifying and compensating for the basic errors of the gyroscope.

This goal is achieved by the fact that in the method of correction of the GK prototype, which includes starting the GK and holding for the time necessary to achieve a steady thermal and electrical state, comparing the GK course with the true stand rate, forming an equal difference in course difference and shifting the GK output rate by correction value, additionally, before the indicated operations, deploy the HA platform around the vertical axis so that the horizontal axis of the HA sensitivity is directed to the north, then turn on the mode iroazimuta and the current is measured in the vertical sensor torque proportional to the angular rate gyro compass control about a horizontal axis Ω _G1, then re-deploy HA platform about a vertical axis so that the horizontal axis of sensitivity HA has been directed to the south, include directional gyroscope mode and again the current is measured in the vertical sensor torque proportional to the control speed Ω _G2 , calculate the drift around the eastern axis according to the formula
P = 0.5 (Ω _G1 + Ω _G2 ).
Form a compensation correction for current according to the formula:
I _p = -RN / K _dm ,
where K _dm [g • cm / a] is the gear ratio of the torque sensor for current;
N [g • cm • s] - kinetic moment of the gyroscope;
and a current I _{p is} supplied to a vertical gyroscope moment sensor.

The theoretical rationale for the method is as follows. After gyro platform rotation rate to 90 ^o and including directional gyroscope mode steady-state speed control Ω about a horizontal axis _T which is proportional to the current in the vertical sensor point, Ω will be given by _G1 = Ucosφ + P.
After turning the gyrocompass platform to a course of 270 ^o, this speed will be determined by the expression Ω _Г2 = -Ucosφ + P. These expressions can be obtained after measuring the currents in a vertical sensor of the moment of the gyroscope or proportional to it control speeds Ω _G1 and Ω _G2 . Then the values of the eastward drift of the gyrocompass are calculated based on the measurements P = 0.5 (Ω _G1 + Ω _G2 ).
The value of the compensation correction to the current is determined by the expression:
I _p = -PH / K _dm ,
where K _dm [g • cm / a] is the gear ratio of the torque sensor for current;
N [g • cm • s] is the kinetic moment of the gyroscope.

Установка платформы ГК на румбы 90^o и 270^o может осуществляться либо вручную, либо подачей большого тока в горизонтальный датчик момента ГК, либо подачей слабого сигнала в усилитель следящей азимутальной системы ГК.After adding a compensation current proportional to the calculated eastward drift to the control current of the vertical moment sensor, the eastward drift of the gyroscope will be compensated and after the gyrocompass mode is turned on, its error in accordance with expression (1) will be determined only by the non-adjustment Δ: ΔK = Δ.
Knowing the true rate of the gyrocompass and comparing it with the output, we calculate the correction to the heading sensor

The installation of the HA platform on the 90 ^° and 270 ^{° rumbas} can be done either manually or by supplying a large current to the horizontal HA moment sensor, or by supplying a weak signal to the amplifier of the tracking azimuthal HA system.

Предложенный способ может быть реализован, например, в конструкции гирокомпаса, структура которого представлена на фиг.2.To determine the signals Ω _G1 , Ω _G2 with an error of 0.005 ^o / h, it is enough to install the GK platform at the courses of 90 ^o and 270 ^o with an error of 1 ^o ÷ 2 ^o . The course correction ΔK can either be added to the output signal of the heading sensor, or displace its signal by additional rotation of the sensor rotor relative to its stator in the zeroed position by an angle at which the signal from the heading sensor is

The proposed method can be implemented, for example, in the construction of a gyrocompass, the structure of which is presented in figure 2.

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

 GK 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 from the accelerometer 8. A current component compensating for the eastward drift to the vertical torque sensor is formed in the electronic unit 6 according to the drift value Р input from the operator console 7. Compensation for the failure Δ is carried out by shifting the signal of the heading sensor.

Claims (1)

A method for correcting a gyrocompass, including starting the gyrocompass and holding it for the time necessary to achieve a steady thermal and electric state, comparing the gyrocompass rate with the true stand rate, forming a correction equal to the difference in course, and shifting the output gyrocompass rate by the correction value, characterized in that, in order to increase accuracy by identifying and compensating for the basic errors of the gyroscope, before the indicated operations, the wok gyrocompass platform is additionally deployed circle the vertical axis so that the horizontal axis of sensitivity is directed to the north, then turn on the gyro-azimuth mode and measure the current in the vertical torque sensor, proportional to the angular velocity of the gyrocompass control around the horizontal axis Ω _G1 , then re-deploy the gyrocompass platform around the vertical axis so that the horizontal axis the gyrocompass sensitivity was directed south, turn on the gyro-azimuth mode and again measure the current in the vertical torque sensor, proportional to the control speed Ω _G2 , calculate the drift around the eastern axis according to the formula P = 0.5 (Ω _G1 + Ω _G2 ), form a compensation correction to the current according to the formula
I _p = -RN / K _dm ,
where K _dm [g • cm / a] is the gear ratio of the torque sensor for current;
N [g • cm • s] - kinetic moment of the gyroscope,
and a current I _{p is} applied to a vertical gyro moment sensor.

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