RU2516369C2 - Method to produce scale ratio of fibre-optic gyroscope - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: in the method to produce a scale ratio of a fibre-optic gyroscope (FOG) they perform angular movement of FOG in the form of its oscillating motion with the specified angular speed within the limits of the selected angle of swinging between two fixed positions. At the same time the value of angular motion is selected as multiple to the value of the swinging angle, and the value of integral of the output signal of FOG is determined in the form of an integral of the module of this signal averaged by quantity of oscillation periods, duration of each from the moment of period start and to the period end is defined by moments of achievement of fixed positions of the swinging angle.

EFFECT: provision of the possibility of simple and efficient detection of scale ratio of FOG.

3 cl, 1 dwg

Description

The invention relates to a technique for calibrating rotary-sensitive devices without moving masses and can be used in the development and manufacture of fiber-optic gyroscopes (FOG).

A known method of calibrating gyro-inertial meters of the strapdown inertial navigation system (SINS) of the spacecraft orientation (see, RF patent No. 2092402 with priority from 05/27/1992, IPC: B64G 1/24), based on the processing of measurements of errors of the strap-on orientation system made using systems of astro sensors before and after each of the three plane rotations of the spacecraft, made around its connected axes by angles not multiple of 360 °, for example, 90 ° or 180 °. As a result, the errors of the scale factors of the gyroinertial meters, the errors of the position of the sensitivity axes and the resulting multiplicative error of the SINS, the calibration algorithm of which is carried out using the on-board computing device, are estimated.

Provided for using the known method, the estimation and, accordingly, the possibility of compensating for the SINS multiplicative error makes it possible to increase the accuracy of the orientation of the spacecraft, however, the implementation of this method is fraught with significant technical and computational difficulties.

The closest analogue to the prototype is a method for calibrating the sensitive elements of a strapdown inertial navigation system (SINS) (see, for example, RF patent No. 23334947 with priority dated March 26, 2007, IPC: G01C 25/00), including determining the scale factors of the angle sensors speeds (TLS) by processing their signals and comparing the information received with information from angle sensors.

This method of calibrating the TLS is based on the use of a two-axis gimbal SINS suspension and providing a special arrangement of the measuring axes of the sensors relative to the axes of this suspension, which is technically difficult to accomplish.

The objective of the invention is to develop a method that enables a relatively simple and effective determination of the scale factor of a fiber optic gyroscope.

The essence of the invention lies in the fact that in the proposed method for obtaining the scale factor of a fiber optic gyroscope (FOG), based on determining the ratio of the integrals of the output signal of the FOG and its angular displacement, the angular displacement of the VOG is carried out in the form of its oscillatory motion with a given angular velocity in within the selected swing angle between two fixed positions, while the magnitude of the angular displacement is a multiple of the swing angle, and the value of the integral of the output Nala FOG is defined as the integral of the signal module, averaged by the number of oscillation periods, the duration of each of which from the beginning to the end of a period determined by the moments of reaching the fixed positions of swing angle.

In addition, the swing angle is chosen equal to from 1 to 10 degrees, the angular velocity of the oscillatory motion is set in the range of 1-15 degrees / second, and the angular displacement is selected equal to 1-10 values of the swing angle.

The technical result from the use of the invention is to enable simple and effective determination of the scale factor of FOG.

Figure 1 shows a diagram of a sample device made to test the proposed method for obtaining the scale factor of a fiber optic gyroscope.

It is indicated here: 1 - base; 2 - crank; 3 - coupling; 4 - lever; 5 - platform; 6 - fiber optic gyroscope.

A method of obtaining a scale factor of VOG is as follows.

Using the crank 2 (Fig. 1) connected with the platform 5, alternating angular displacements of the fiber-optic gyroscope 6 installed on this platform are made, made in the form of a fiber loop coil based on a single-mode polarization-resistant quartz fiber (see, for example, patent RF №2139499 with priority dated 03.03.1998, IPC: G01C 19/72) 100 m long with a radiating module in the form of a superluminescent diode of the SLD-2-2 type (see, for example, http: //www.mject-laser .ru / products / diodes) and with a photodetector module - based on a frameless photodiode type SSO-PDQ-0.25- 5SMD (see, for example, http://www.datasheetdir.com/SSO-PDQ-0.25-5+Photodiode). The diameter of the fiber loop coil was -70 mm.

The magnitude of the scale factor (MK) is determined from the ratio:

, $$MK={\displaystyle \underset{0}{\overset{T}{\int }}|\; |\; |U\left(t\right)|\; |\; |dt/\mathrm{four}A}$$

,

where U (t) is the output signal of VOG; A - angle of rotation - parameter of the swinging table; 2A is a swing angle from one fixed position to another (see FIG. 1); T is the period of angular oscillations - it is measured by the moments of transition through zero of the output signal (voltage) U (t) of the FOG (the moments of the change in sign of the output signal of the FOG when fixed positions are reached).

The proposed method takes into account the specific feature of VOG associated with its high speed, which allows using the VOG output signal to determine the period of angular oscillations without the use of additional equipment.

To implement the method requires registration (integration) of the output signal of the VOG. In a sample device manufactured to test the proposed method, the output signal was recorded by analog-to-digital conversion followed by a computer (not shown) to integrate digital data and determine the moments of the output signal passing through zero.

Angular oscillatory motion between fixed positions can be realized by simple means with small dimensions of the device. In this case, the swing angle during the implementation of the proposed method is chosen only for reasons of constructive expediency, and in order to avoid the influence of non-linearity of the output characteristic of the sensor on the measurement accuracy, the maximum angular velocity should not be large.

The inventive method with a positive result has been tested for swing angles in the range from 1 to 10 degrees at maximum angular speeds of 1-15 degrees / second.

Claims (3)

1. A method of obtaining a scale factor of a fiber optic gyroscope (FOG), based on determining the ratio of the integrals of the output signal of the FOG and its angular displacement, characterized in that the angular displacement of the VOG is carried out in the form of its oscillatory motion with a given angular velocity within the selected swing angle between two fixed positions, and the magnitude of the angular displacement is a multiple of the magnitude of the swing angle, and the magnitude of the integral of the output VOG signal is determined as the integral of the modes To this signal is averaged by the number of oscillation periods, the duration of each of which from the beginning to the end of a period determined by the moments of reaching the fixed positions of swing angle. 2. The method of obtaining the scale factor of a fiber optic gyroscope (FOG) according to claim 1, characterized in that the swing angle is selected from 1 to 10 degrees, and the angular velocity of the oscillatory motion is set in the range of 1-15 degrees / sec. 3. The method of obtaining the scale factor of a fiber optic gyroscope (FOG) according to claim 1 or 2, characterized in that the angular displacement is selected equal to 1-10 values of the angle of swing.