Method for measuring eigen frequency of fiber-optic gyroscope based on sawtooth-wave modulation of even-multiple eigen requency

Abstract

The invention discloses a method for measuring the eigen frequency of a fiber-optic gyroscope based on sawtooth-wave modulation of even-multiple eigen requency, and belongs to the field of fiber-optic gyroscopes. The measurement method comprises the steps that a sawtooth-wave phase modulation signal with the frequency close to the eigen frequency of the even-multiple fiber-optic gyroscope is modulated and generated, and then the signal is superimposed on a square-wave bias modulation signal to generate a superposed modulation signal; two beams of light emitted and transmitted by an optical-fiber sensitive ring are subjected to the phase modulation of the superposed modulation signal, and interference occurs; an interference signal is detected to obtain a phase error generated by the two beams of light during the phase modulation; the frequency of the sawtooth-wave phase modulation signal is changed, the phase error is detected, when the phase error is zero, the frequency of the sawtooth-wave phase modulation signal is exactly even multiples of the eigen frequency, and therefore the eigen frequency of the fiber-optic gyroscope is obtained. Without changing the basic structure of the original digital closed-loop fiber-optic gyroscope, the method for measuring the eigen frequency of the fiber-optic gyroscope can achieve the high-precision measurement of the eigen frequency and provide a means for relative researches.

Description

technical field [0001] The invention belongs to the field of fiber optic gyroscopes, in particular to a fiber optic gyroscope eigenfrequency measurement method based on even-fold eigenfrequency sawtooth wave modulation. Background technique [0002] Fiber optic gyro is an optical angular velocity sensor that appears with the rapid development of fiber optic technology. It has the advantages of an all-solid-state structure without rotating parts, small size, light weight, large dynamic range, shock resistance, and long life. It has been used as a An important inertial sensor is used in aviation, aerospace, navigation and other fields, and the development of fiber optic gyroscope is developing towards high precision. [0003] The eigenfrequency is an extremely important parameter of the fiber optic gyroscope, which is defined by the optical path, specifically: twice the optical path of light propagating in the optical fiber sensitive ring divided by the speed of light. [000...

AI Technical Summary

Problems solved by technology

However, the problem is that the measurement accuracy of the eigenfrequency is not high enough to meet the research needs of high-precision fiber optic gyro, and it is necessary to separate the optical path of the fiber optic gyroscope before measuring

This is a high-precision method to adjust the bias modulation frequency to the eigenfrequency of the fiber optic gyroscope, but this method not only needs to change the optical path structure, but also needs to add an additional phase modulator in the optical path, and needs to change the circuit structure, Adding components such as comparators makes the circuit very complicated and increases the cost of the device

[0010] Existing methods for the measurement of eigenfrequency are generally not high in accuracy, and it is difficult to meet the needs of developing high-precision fiber optic gyroscopes, and the structure is relatively complicated. Therefore, a simple and easy high-precision measurement method for eigenfrequency is needed

Images