RU2436046C1 - Gyrohorizoncompass with inertia measurement unit rotation - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: gyrohorizoncompass contains a measurement module designed in the form of a medium accuracy fibre-optic gyroscope triad, an accelerometre triad and an onboard computer; the measurement axes of the gyroscopes and the accelerometres are mutually orthogonal and parallel to each other. For automatic compensation for transducers instrumental errors one has provided for modulation rotation of the measurement module around an axis perpendicular to the base plane. Correction of the gyrohorizoncompass output data is performed by a satellite navigation system data. The method for determination of the gyrohorizoncompass navigation parameters is based on usage of signals of the unit of accelerometres and fibre-optic gyroscopes for calculation of the directional cosines matrix. One has provided for automatic switchover to the operational mode wherein the vertical is in an undisturbed and an undamped modes while the compass line is in the proazimuth mode.

EFFECT: increased accuracy.

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Description

The invention relates to orientation systems and navigation systems for moving objects of various types, in particular to gyrohorizon compasses (GGC), which use measurement information obtained from angular velocity sensors (DLS) (fiber optic or other type) and from the unit of accelerometers.

Known strapdown inertial navigation systems (SINS) [Integrated orientation and navigation systems for marine moving objects / ON, Anuchin, GI Emelyantsev / Ed. Academician of the RAS V.G. Peshekhonov. Ed. 2nd, revised and supplemented. - SPb .: SSC RF - Central Research Institute "Elektropribor", 2003].

The information basis for measuring the dynamic parameters (linear and angular) of the SINS object’s movement is made up of a measuring unit (IS) and an information control, monitoring and processing device, the IS includes three linear accelerometers and three TLS (fiber-optic or other type), and modulation spreads are also provided IB around an axis perpendicular to the plane of the deck, in the range of ± 180 °. The signals of the remote control system, accelerometers, and the angle sensor signal about the angle of rotation of the information security relative to the housing are used to calculate the matrix of directional cosines between the connected and navigation coordinate system, which is used to convert the apparent accelerations measured by linear accelerometers and generate the SINS output data. It is planned to combine IS data with data received from the satellite navigation system (SNA).

As a prototype for the largest number of common essential features was adopted GGK [Ignatiev S.V. Girogorizontkompas on fiber-optic gyroscopes with rotation of the block of sensitive elements // Navigation and motion control. Sat reports of the IV conference of young scientists. SPb .: State Research Center of the Russian Federation - Central Research Institute "Elektropribor", 2002. S.291-298], containing a measuring module (MI) on fiber-optic gyroscopes (FOG) and accelerometers with built-in electronics, as well as an on-board computer located on a rotating platform around an axis perpendicular to the plane of the base. The rotation is provided by a gearless drive, the operation of which is controlled by a microcontroller connected to the on-board computer. Electrical connections of the moving part with a fixed base are made through a sliding current supply of unlimited rotation with multiple redundancy of the main communication lines. Communication with the satellite navigation system (SNA) receiver and the consumer is carried out via the RS232 serial interface. GGK, built on average precision VOG (drift of the order of 10 - 1 ° / hour), does not provide the necessary accuracy in determining the course. In this regard, the scheme of auto-compensation of departures of horizontal FOGs was applied and, as a result, the required accuracy is achieved when the object moves at a constant speed and course. The on-board computer receives data from the MI in the form of three angular velocities and three accelerations, the angle of rotation of the drive rotation, external information from the SNA and, solving the problem of generating orientation and translational motion parameters, builds a vertical and course with a period significantly shorter than the Schuler period, adjusting the output according to information from the SNA.

The disadvantage of the prototype device is that, when solving problems of generating orientation and translational motion parameters, a vertical with a short period is simulated in the on-board computer, which, when maneuvering the object and immediately after the maneuver, as well as during the short-term loss of external information signals from the SNA, leads to that the vertical of the place is indignant and, therefore, errors in the construction of the vertical and course guidance can reach significant values.

The objective of the invention is to increase the accuracy of the generation of orientation parameters. The problem is solved by the fact that a mode control unit is introduced into the on-board computer, which, to reduce the influence of accelerations that occur when maneuvering the object or during short-term loss of external information signals from the SNA, implements an automatic transition to an operation mode in which the vertical operates in an unperturbed and undamped mode with the Schuler period, and the compass line operates in the gyro azimuth mode.

The invention is illustrated by drawings, where in Fig. 1 the design elements of the device are indicated, in Fig. 2 is a block diagram of an on-board computer, in Fig. 3 is a diagram of a vertical construction loop, in Fig. 4 is a diagram of a building block of a directional channel:

1 - VOG triad;

2 - triad of accelerometers;

3 - rotating shaft;

4 - torque engine;

5 - shaft angle sensor;

6 - the body of the device;

7 - analog-to-digital Converter;

8 - on-board computer;

9 - output connectors;

10 - sliding circular current lead;

11 - block generating orientation parameters;

12 - block conversion of apparent accelerations;

13 - block development of the parameters of the translational motion;

14 - block building a vertical;

15 - block building a course channel;

16 - mode control unit;

17, 19, 22, 24, 25, 30, 32 - adder;

18, 27, 29, 33 - integrator;

20 - stationary filter F (p);

21 - multiplication by the acceleration of gravity g;

23 - division by the radius of the Earth R;

26 - error in accounting for the horizontal component of the Earth’s rotation speed due to inaccurate knowledge of the course, ΔК · Ω · cosφ;

28, 31 - dividing by the time constant of the course channel T _z ;

34 - coefficient of reduction of dimensions To _z ;

a _E , a _N , a _h - linear accelerations of the object in the projection on the axis of the geographic coordinate system;

a _X , a _Y , a _Z - linear accelerations of the object in projection on the axis of the coordinate system associated with the device;

- матрица перехода от связанной с прибором системы координат к географической системе координат;

- transition matrix from the coordinate system associated with the device to the geographical coordinate system;

V _E , V _N , V _h - linear velocity of the object in projection on the axis of the geographic coordinate system;

,

,

- линейные скорости объекта в проекции на оси географической системы координат, получаемые от СНС;

,

,

- linear velocity of the object in projection on the axis of the geographical coordinate system, obtained from the SNA;

α, β are the errors in constructing the vertical of the place;

φ, λ - location coordinates generated by the device;

φ ^SNA , λ ^SNA - location coordinates received from the SNA;

K, ψ, θ - heading, pitch and pitching angles generated by the device;

ρ is the angle measured by the shaft angle sensor 5;

ω _X , ω _Y , ω _Z are the angular velocities of rotation in the projection on the axis of the coordinate system associated with the device;

ΔK is the error in determining the course;

ΔV _N is the difference of the northern components of the speeds generated by the device and obtained from the SNA;

δω _E , δω _Z - drift of the "east" and azimuthal gyroscopes.

The GGC of the presented design operates as follows.

An inertial measuring module, in the form of a VOG triad 1 and accelerometer triad 2, in which the measuring axes of the gyroscopes are mutually orthogonal, and the measuring axes of the accelerometers are parallel to the axes of the gyroscopes, mounted on a rotating shaft 3 with ball bearings, on which the rotor of the torque motor 4 and the rotor are also mounted the angle sensor of rotation of the shaft 5, and the stator of the torque motor 4 and the electric converter of the angle sensor of rotation of the shaft 5 are installed on the housing of the device 6, the outputs of the VOG 1 triad and tr the accelerometer arms 2 are connected to the corresponding inputs of an analog-to-digital converter (ADC) 7, the output of which is connected to the input of the on-board computer 8, which generates orientation parameters, as a communication device for the outputs of the on-board computer 8 with output connectors 9 located on the housing 6, a circular current supply 10.

. Из элементов матрицы

рассчитываются углы курса, бортовой и килевой качки К, ψ, θ, которые являются выходными данными ГГК. Линейные ускорения a_X, a_Y, a_Z, измеряемые триадой акселерометров 2, а также матрица

поступают на вход блока преобразования кажущихся ускорений 12, где линейные ускорения a_X, a_Y, a_Z в ССК преобразовываются в линейные ускорения a_E, a_N, a_h в ГСК. Линейные ускорения a_E, a_N, a_h поступают на вход блока выработки параметров поступательного движения 13, где вычисляются линейные скорости объекта в ГСК V_E, V_N, V_h, а также координаты места φ и λ, которые корректируются по данным о линейных скоростях

,

,

и координатах места φ^СНС и λ^СНС, получаемых от СНС. Вычисленные координаты места φ и λ поступают на вход блока выработки параметров ориентации 11.The angular rotational speeds ω _X , ω _Y , ω _Z measured by the VOG 1 triad and converted by the ADC 8 from an analog signal to a digital signal, as well as the angle ρ measured by the shaft angle sensor 5, enter the block for generating orientation parameters 11, where according to these data , and also according to the data on the coordinates of the place φ and λ, a transition matrix is formed from the coordinate system associated with the device (SSC) to the geographical coordinate system (SSC)

. From the elements of the matrix

the angles of the course, side and pitching K, ψ, θ, which are the output of the GGC, are calculated. Linear accelerations a _X , a _Y , a _Z , measured by the triad of accelerometers 2, as well as the matrix

arrive at the input of the apparent acceleration conversion unit 12, where the linear accelerations a _X , a _Y , a _Z in the SSC are converted into linear accelerations a _E , a _N , a _h in the SSC. Linear accelerations a _E , a _N , a _h go to the input of the translational motion generation block 13, where the linear velocities of the object in the GSK V _E , V _N , V _h are calculated, as well as the coordinates of the place φ and λ, which are corrected according to linear speeds

,

,

and the coordinates of the place φ ^SNA and λ ^SNA received from the SNA. The calculated coordinates of the place φ and λ are fed to the input of the block generating orientation parameters 11.

,

,

поступают на вход контура построения вертикали 14, где формируются погрешности построения вертикали места α и β. Блок-схема контура построения вертикали приведена на фиг.3. За основу взят контур Шулера, корректируемый по данным от приемника СНС. В цепи коррекции используется стационарный фильтр 20 с передаточной функцией:Linear velocity data V _E , V _N , V _h and

,

,

arrive at the input of the vertical construction contour 14, where the errors of the vertical construction of the place α and β are formed. The block diagram of the contour of the vertical is shown in Fig.3. The basis is the Schuler circuit, corrected according to data from the SNA receiver. In the correction circuit, a stationary filter 20 with a transfer function is used:

,

,

- постоянная времени Шулера,Where

is the time constant of Schuler,

T _B << T _W - the time constant of the vertical channel.

,

,

формируются разности скоростей ΔV_E, ΔV_N, которые поступают на вход фильтра 20. Вход фильтра 20 суммируется с выходом интегратора 18, делится на радиус Земли и поступает на вход второго интегратора 27. Принцип гирокомпасирования основан на том, что в выходном сигнале "восточного" гироскопа содержится составляющая Ω·cos(φ)·ΔК, где Ω - скорость вращения Земли, φ - широта места.According to the linear velocity data V _E , V _N , V _h and

,

,

speed differences ΔV _E , ΔV _{N are formed} , which are fed to the input of the filter 20. The input of the filter 20 is summed with the output of the integrator 18, divided by the radius of the Earth and fed to the input of the second integrator 27. The principle of gyrocompassing is based on the fact that the output signal is "east" the gyroscope contains the component Ω · cos (φ) · ΔК, where Ω is the speed of rotation of the Earth, φ is the latitude of the place.

Data on the difference of the northern component of the velocity ΔV _{N is} fed to the input of the block for constructing the course channel 14, where the error in determining the course ΔK is generated. The block diagram of the block building the course channel is shown in figure 4. The course channel of the GGC can be considered as a tracking system, resetting the readings of the "eastern" gyroscope. The main error in the course guidance is associated with the drift of the “eastern” gyroscope δω _E , to compensate for the influence of this drift, self-compensation rotation was applied. To exclude the influence of the constant component of the drift velocity of the “vertical” gyroscope δω _Z on the course guidance, an isodromic link is included in the channel.

Data on the errors in constructing the vertical of the place α and β and determining the ΔK course are fed to the input of the block for generating orientation parameters 10, for adjusting the orientation parameters K, ψ, θ.

When the signal from the SNA disappears or when maneuvering, the speed difference ΔV _E , ΔV _N starts to grow, as a result of which the vertical is perturbed, and the errors of the vertical and course guidance begin to increase significantly.

,

,

и курсе К блок управления режимами 15 формирует сигналы «Маневр» и «Конец маневра» и осуществляет автоматическое переключение между двумя режимами работы:A feature of this device is the presence in the on-board computer 7 mode control unit 15. According to the data on the linear speeds V _E , V _N , V _h and

,

,

and course K, the mode control unit 15 generates the signals “Maneuver” and “End of maneuver” and automatically switches between two operating modes:

- regular mode, which is characterized by the presence of a short-period vertical and gyrocompass scheme;

- autonomous mode, which occurs when the signal “Maneuver” is received or when the signal disappears or is unreliable from the SNA and stops when the signal “End of maneuver” is received or the signal from the SNA is resumed. At the same time, at least one of the above signals is sufficient to go into stand-alone mode, and two signals must be present simultaneously to go to normal mode: “End of maneuver” and the reliability of information from the SNA. In standalone mode, the vertical is set for the Schuler period, and the gyrocompass line goes into gyro azimuth mode.

The following algorithm for generating signals “Maneuver” and “End of maneuver” is used.

We introduce the notation of the current increments of the linear velocity and the instrumental course:

dV _e (i); dV _n (i); dK _P (i),

where i is the current value of the calculation clock.

The total value of the increment of the linear velocity and the instrument course for n1 and n2 ticks, respectively, is determined by the moving average in accordance with the expressions:

;

;

;

;

where m takes values from 1 to the last measure of implementation.

Definition of signals “Maneuver” and “End of maneuver”

If ΔK _P (m)> ΔK _d ; ΔV (m)> ΔV _d , then the signal "Maneuver",

if ΔK _P (m) ≤ΔK _d ; ΔV (m) ≤ΔV _d , signal "End of maneuver",

where ΔK _d , ΔV _d is the permissible change in the instrumental course and speed increments, respectively.

Switching from the normal mode to the autonomous mode is performed as follows: both in the vertical line and in the course line, the speed difference ΔV _E , ΔV _N ceases to come to the filter inputs; the inputs and outputs of the filters are frozen and, therefore, the vertical operates in an unperturbed and non-damped mode with a Schuler period, and the compass line operates in gyro azimuth mode.

,

,

. При этом для уменьшения переходного процесса непосредственно после перехода в штатный режим применяется следующий алгоритм.The reverse transition from the offline mode to the standard one occurs when information on the SNA speed is resumed and in the absence of the “Maneuver” signal, the signal to the inputs of the vertical and directional channel filters is resumed and a difference is formed between the current speed of the device V _E , V _N , V _h and speed from the SNS

,

,

. In this case, to reduce the transient process immediately after the transition to the normal mode, the following algorithm is used.

Let ΔV ₁ be the signal at the filter input at the moment of transition to the autonomous mode, and ΔV ₂ be the signal at the filter input at the transition to the normal mode. Then

.

.

where ΔV ^' (m) = ΔV ₂ , with m corresponding to the moment of transition to the normal mode, hereinafter m changes in accordance with the current data of SINS and SNA;

ΔV (m) is the signal at the inputs of the vertical and heading filters.

Claims (1)

The gyrohorizontcompass, consisting of an inertial measuring module made in the form of a triad of fiber optic gyroscopes and a triad of accelerometers mounted on a rotating shaft, while the measuring axes of gyroscopes and accelerometers are mutually orthogonal and parallel, the rotor of the torque motor and the rotor of the shaft angle sensor mounted on a rotating shaft, as well as located in the housing of the stator of the torque motor and the electric converter of the shaft angle sensor, on-board computer, mounted on a rotating shaft containing a unit for generating orientation parameters, a unit for transforming apparent accelerations, a unit for generating translational parameters, a vertical construction loop, a channel building block, the inputs of the on-board computer are connected via an analog-to-digital converter to the outputs of the triad of fiber-optic gyroscopes and triad of accelerometers, and the outputs of the on-board computer are connected to the output connectors of the device located in the housing, by means of a sliding circle power supply, characterized in that the on-board computer additionally contains a mode control unit when maneuvering the object or when external information signals from satellite navigation systems disappear for a short time, the device automatically switches to an operating mode in which the vertical construction loop operates in an unperturbed and non-damped mode with Schuler’s period, and the block for constructing the course channel works in gyro azimuth mode.

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