Measurement for eigenfrequency of interferometric type fiber-optic gyroscope by using asymmetrical square wave modulation method

A modulation frequency, fiber optic gyroscope technology, applied in the measurement of resonant frequency, measurement device, Sagnac effect gyroscope and other directions, can solve the problem of modulation error affecting gyroscope performance and other problems, achieve high real-time, accurate measurement, fast adjustment speed Effect

Inactive Publication Date: 2007-05-23
BEIHANG UNIV
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Problems solved by technology

The length L and refractive index n of the optical fiber are greatly affected by the curvature, strength and ambient temperature of the optical fiber, which causes the eigenfrequency of the fiber optic gyroscope to change with external factors. The fixed value estimated by the traditional method cannot be accurately equal to the eigenfrequency , thus introducing modulation error to affect the performance of the gyroscope

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  • Measurement for eigenfrequency of interferometric type fiber-optic gyroscope by using asymmetrical square wave modulation method
  • Measurement for eigenfrequency of interferometric type fiber-optic gyroscope by using asymmetrical square wave modulation method
  • Measurement for eigenfrequency of interferometric type fiber-optic gyroscope by using asymmetrical square wave modulation method

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Embodiment Construction

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0027] The present invention is a method of measuring the eigenfrequency of an interferometric fiber optic gyroscope using an asymmetrical square wave modulation method. The measuring method has the following steps:

[0028] (A) FPGA controls DDS to generate initial modulation frequency f 0 = C 2 nL Below asymmetrical square wave, L is the fiber length of fiber ring (4), n is the refractive index of fiber, and C is the speed of light in vacuum;

[0029] (B) after the asymmetrical square wave is loaded into the Y waveguide 3 for phase modulation after the D / A converter 64 and the amplification conditioning circuit 65;

[0030] (C) The detector 5 receives the first optical power information P(Δt after interference 1 ), the second optical powe...

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Abstract

The invention discloses an asymmetric square wave modulation method to measure interference fiber gyro eigenfrequency. By controlling module FPGA, the method controls DDS to generate different frequency asymmetric square wave to process phase modulation to Y waveguide; and the signal processing module DSP real-time calculates the margin absolute DeltPd of the accumulation in A/D sampling time T, and processes the absolute minimum judgment to the said margin absolute DeltPd, and when the margin absolute DeltPd close to zero, gets the fiber gyro eigenfrequency fe equaling modulation frequency fd. Such measurement method measures the eigenfrequency Fe with high accuracy, and frequency tracking speed adjustment quick, and highly real-time.

Description

technical field [0001] The invention relates to a method for measuring the eigenfrequency of an interference fiber optic gyroscope, more particularly, a method for measuring the eigenfrequency of an interference fiber optic gyroscope by using an asymmetrical square wave modulation method. Background technique [0002] The interferometric fiber optic gyroscope is an instrument for measuring angular velocity. Its hardware consists of a light source 1, a coupler 2, a Y waveguide 3, an optical fiber ring 4, a detector 5 and a signal processing device 6 (see Figure 1). Described signal processing device 6 comprises the detection circuit 61, A / D converter 62, central processing unit 63, D / A converter 64 and amplification conditioning circuit 65 that are used to detect the optical power signal that detector 5 outputs to form (please See Figure 2). The measurement of the angular velocity of the interference fiber optic gyroscope is characterized by the size of the non-reciprocal ph...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01C19/72G01P9/00G01P21/00G01H13/00G01H17/00G01C19/64
Inventor 金靖吕峰建宋凝芳李敏田海亭徐小斌
Owner BEIHANG UNIV
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