RU2296299C1 - Method for determining direction of true meridian of ground transport - Google Patents

Abstract

FIELD: technology for determining direction of true meridian of objects on Earth for navigational and topographic purposes.

SUBSTANCE: mounted on a platform are n+1 angular speed indicators (n=1,2,3...), sensitivity axes of which are located either in plane of platform or along a cone at an angle of 45° to platform plane, positioning them at an angle of 360°/(n+1) to each other, and oscillating movement is performed for angle ±(360/(n+1))+Δ(Δ - value of overlapping angle) with constant angular speed greater than angular speed of transport within limits 360/(n+1), determined further is dependency of horizontal component of angular speed of earth on rotation angle of platform, determined are minimum and maximum and azimuth angle appropriate to each of them is computed. In random position of platform relatively to horizon plane, pitching and banking angles of sensitive axis of one of angular speed indicators are measured and azimuth angle is computed, with consideration of change of projections of angular speed of Earth rotation.

EFFECT: decreased determining time and increased precision.

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Description

The invention relates to determining the direction of the true meridian of objects on earth for navigation or topographic purposes.

A known north direction indicator on a fiber-optic gyroscope [1], where the gyroscope is mounted on an approximately horizontal platform and is driven by 4 consecutive angular positions with an interval of 90 °, the gyroscope signal is averaged by a computer at each position of azimuthal points. The disadvantage of this pointer is that the method of determining the direction to the north requires a 360 ° rotation of the platform and the introduction of a current lead, thereby increasing the time for determining the meridian.

A known method for determining the angular displacements of an object with a laser gyroscope [2], which consists in the fact that the ring laser is driven into oscillation relative to the base, generate the main frequency-stabilized and additional pulse sequence, measure the output signal of the laser gyro for the time between pulses of the additional sequence, measure the intervals time between pulses of the additional sequence and between pulses of the main and additional sequences, and the output The laser gyroscope signal for the time between pulses of the main sequence is determined using measured values, the angular velocity of the laser oscillations relative to the base is additionally measured, additional sequence pulses are generated at times when this speed is zero, and the output of the laser gyroscope is measured as between even numbers, and between odd pulses of an additional sequence. This method simplifies the implementation, while maintaining accuracy, the determination of angular displacements. The disadvantage is the dependence of accuracy on the amplitude of the angular oscillations and the nature of its change from time to time. In a technical solution, this law is adopted linear.

A device for determining the direction to the north [3], containing three fixed angular velocity sensors, the angles between the directions of the axes of sensitivity of which are 120 °, located in the horizontal plane. The north direction is determined based on the maximum value of the sine curve of the signal received from the sensors on the operating module. The disadvantage of this device is the stationary position of the sensors and a strictly horizontal position of the platform, because of which there is no possibility of compensation for the drift of the output signals of the sensors from the inclination of the platform.

Known laser gyrocompass 9A184 [4], a static type that measures the projection of gravity acceleration on the measuring axis of the accelerometer and the projection of the angular velocity of rotation of the earth on the sensitivity axis of the laser angular velocity sensor, which is located in the horizontal plane. The measurement unit includes a turning device in the form of a stepper motor with 8 positions, of which four working positions through 90 ° ± 5 '' are used, a laser remote control system, two accelerometers, a platform angular position sensor, and an electronics unit. This gyrocompass has an azimuth determination time of 8 minutes, the azimuth error with a probability of 0.9 no more than 10 '. The disadvantage of this indicator is that the method of determining the direction to the north requires a 360 ° rotation of the platform, thereby increasing the time for determining the meridian.

A known method for determining the direction of the true meridian [5], in which the FOG is set so that its sensitivity vector is in the horizontal plane, rotate the FOG around an axis perpendicular to the horizontal plane by rotating it with a constant angular velocity so that its sensitivity vector remains in plane of the horizon, measure the output signal by phase detection at the rotational speed, while determining the phase of the output signal of the FOG, corresponding to Mutu. The method improves the accuracy of determining the direction of the true meridian. Its disadvantages are a significant determination time due to the need for a full turn of the platform and low accuracy due to noise in the collector pair of the current collector of the device that implements the method.

The main frequencies of the spectral composition of electrical noise generated by passing a direct current through the contact of the elements are in the range from 0 to 1.5 kHz and are 1 / f. With a decrease in the sliding speed of the elements, the spectrum shifts to the region of lower frequencies. The maximum amplitude of contact noise is 22 μV [6]. For a laser gyrocompass, this leads to an increase in the error by a factor of 2.

The objective of the invention is to reduce the determination time and increase the accuracy of determining the direction of the true meridian of ground transport by introducing a flexible current supply and reducing the signal-to-noise ratio.

The problem is solved as follows: in the method of determining the direction of the true meridian of ground transport, in which the angular velocity sensor is rotated with an angular velocity around an axis perpendicular to the horizon plane, the angle of rotation of the platform and the output signal of the angular velocity sensor are measured, the azimuth is determined, characterized in that n + 1 angular velocity sensors (n = 1, 2, 3 ...) are installed on the platform, the sensitivity axes of which are located either in the plane of the platform, or along a cone at an angle of 45 glad to the plane of the platform, placing them at an angle of 360 / (n + 1) to each other, and carry out oscillatory motion at an angle of ± (360 / (n + 1)) + Δ (Δ is the value of the overlap angle) with an angular velocity greater than the angular transport speeds within the angle of 360 / (n + 1), using the output signals of the sensors, build the dependence of the horizontal component of the angular velocity of the Earth on the angle of rotation of the platform, find its maximum and minimum, and calculate the corresponding azimuth angle. With the sensor location options, the roll and pitch angles of the sensitivity axis of one of the angular velocity sensors from the roll and pitch angle sensors are measured, and the azimuth angle is calculated taking into account changes in the projections of the angular velocity of the Earth's rotation.

The invention is illustrated by the following drawings.

Figure 1 shows a device for implementing the proposed method with sensors, the sensitivity axis of which are located in the same plane.

Figure 2 presents a device for implementing the proposed method with an orthogonal arrangement of the axes of sensitivity of the sensors.

Figure 3 presents the timing diagram of work.

The device consists of a rotating platform 1, on which angular velocity sensors 2 are mounted, located at an angle α to each other, the sensitivity axes of which are perpendicular to the axis of rotation of the platform and are located in the plane of platform 1. In the case of an orthogonal arrangement of the instrument trihedron of angular velocity sensors 2 of their sensitivity axis they are arranged conically at an angle of 45 ° to the plane of platform 1. The angle α for three TLSs with the axes of sensitivity in the radial direction is 120 °, for four - 90 °, for six - 60 °. The roll angle and pitch sensors 3, 4 with the orientation of the sensitivity axes along the sensor 2 ₁ and perpendicular to it are located in the plane of the platform 1. Platform 1 is mounted on the axis 5 in bearings 6 (ball bearings). On the axis 5 of the suspension of the platform 1 are the angle sensor 7 of rotation around the Z axis and the belt wheel 8. Another gear wheel 9 is mounted on the shaft of the engine 10. Power is supplied to the angular velocity sensors 2 and their output signal is removed through flexible current leads 11 to the control and display unit 12. The inputs of the sensors 2-4 are connected to the power supply 13.

The proposed method for determining the direction of the true meridian of ground transport is as follows. Platform 1, for example, with three angular velocity sensors 2 ₁ , 2 ₂ , 2 ₃ , located at an angle of 120 °, is set so that the sensitivity vectors of the sensors 2 were in the plane of the platform around an axis perpendicular to it. For the variant of the orthogonal arrangement of the instrument trihedron of the angular velocity sensors 2 (Fig. 2), their sensitivity axes are conically angled at a 45 ° angle to the plane of the platform 1. Carry out angular rotations of the platform 1 in supports around the Z axis using the engine 10 through a transmission with wheels 8, 9 by an angle of ± 60 ° + Δ (Δ is the value of the overlap angle) with a constant angular velocity greater than the angular velocity of the transport within 60 ° around an axis perpendicular to the plane of the platform. The angular position of the platform 1 in the process of oscillations is controlled by an angle sensor 7. The electrical signals recorded from the sensors 2 during angular vibrations of the platform 1 around the vertical axis Z in the positive and negative direction of rotation of the platform 1 are added and averaged. In this case, the projections of the angular velocity of rotation of the platform 1 on the sensitivity axis of the sensors 2 with their orthogonal arrangement will be compensated and excluded from further processing; likewise will be partially compensated for drift of zero sensor signal 2. As a result, the electrical sensor signals ₁ 2, 2 _2, March ₂ will have a sensor with an analog output type harmonic function U _i = k _i ω _s cosφcos (2πƒ ₀ t + α + α _yi ) + U _0i , limited by angles of ± 60 °, selected from among the sensors and permissible rotation angles of the current lead; here U _0i are the drifts of zero signals of the i-th sensor with an analog output; k _i - calibrated scale factors of the i-th sensor with analog output, ω _z - angular velocity of rotation of the earth, φ - geographical latitude of the earth, α - azimuth angle, α _yi - angle of the initial installation of the i-sensor (0 °, 120 ° , 240 °). The type of signals at azimuth angles (φ = 0 °, 90 ° and at an arbitrary angle φ 'is shown in the time diagram of the installation of the ith sensor (0 °, 120 °, 240 °). The type of signals at azimuth angles φ = 0 °, 90 ° and for an arbitrary angle φ 'is shown in the time diagram of operation (Fig. 2). Algorithmically, a single harmonic function curve is formed from the segments of the sensor signals 2 ₁ , 2 ₂ , 2 ₃ . 2 ₁ , 2 ₂ , 2 ₃ Δψ _i relative to the reference point determined by the angle sensor 11. The azimuth angle is I by the formula ψ = Δψ _i + α _yi .

The measurement of the roll angles and pitch of the platform 1 turning from the horizon plane is carried out using the roll and pitch angle sensors 3 and 4.

With a horizontal arrangement of the platform and three angular velocity sensors, the signals from the sensors 2 have the form:

If there are pitch angles 9, the signals of the sensors 2 will take the form:

If there are roll angles γ, the signals of the sensors 2 will take the form:

To determine the azimuth of the platform, we multiply the amplitudes of the signals U _i by the coefficients:

- in system (1) on

соответственно;- in system (2) on

respectively;

соответственно.- in system (3) on

respectively.

Assuming, in a first approximation, the magnitude of the drift of the zero sensor signals is the same, we obtain a shift of the single curve of the harmonic function of the signal in the vertical direction. Subtracting the modules of the maximum and minimum values of the signal, we obtain the value of the zero drift of the sensors, which can be taken into account when processing the sensor signals in a second approximation.

The azimuth of the platform is ψ _max (α _p ) = ψ ₁ (α _n ) + ψ ₂ (α _n ) + ψ ₃ (α _n )

In the proposed method, compared with the prototype increases the accuracy of determining the direction of the true meridian with a technologically advanced and reliable device circuit.

Information sources

1. Dyott R. B., Alien D.E. A fiber optic gyroscope north finder tenth Jut J Conf. On Optical Fiber Sensors, Vol. 2360, SRIE, Glasgow, 11-13 Oct. 1994 - p. 424-448.

2. A.c. SU 13293227, IPC G 01 С 19/64, Method for determining the angular displacements of an object by a laser gyro // Efimov B.V., Polyakovsky E.F. - 1996. - BI No. 16.

3. Japan patent JP 7294258, IPC G 01 C 19/00. A device for determining the direction to the north.

4. Operation manual SKGR 02.07.000RE CJSC Istok.

5. Patent RU 2115889, IPC G 01 C 19/38, 19/64, Method for determining the direction of the true meridian and fiber optic gyrocompass that implements the method // Matisov IA, Nikolaev IA, Strigalev V.E. - 1998.

Claims (2)

1. A method for determining the direction of the true meridian of ground transport, in which the angular velocity sensor is rotated with angular velocity around an axis perpendicular to the horizon plane, the angle of rotation of the platform and the output signal of the angular velocity sensor are measured, the azimuth is determined, characterized in that it is installed on the platform n + 1 angular velocity sensors (n = 1, 2, 3 ...), the sensitivity axes of which are located either in the plane of the platform or cone at an angle of 45 ° to the plane of the platform, placing them at an angle of 360 / ( n + 1) to each other, and they oscillate at an angle of ± (360 / (n + 1)) + Δ (Δ is the value of the overlap angle) with an angular velocity greater than the angular velocity of the transport within 360 / (n + 1), the output signals of the sensors build the dependence of the horizontal component of the angular velocity of the Earth on the angle of rotation of the platform, find its maximum and minimum and calculate the corresponding azimuth angle. 2. The method of determining the direction of the true meridian of land transport according to claim 1, characterized in that the heel and pitch angles of the sensitivity axis of one of the angular velocity sensors from the heights and pitch sensors are measured and the azimuth angle is calculated taking into account changes in the projections of the angular velocity of the Earth.

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