Low Cost Method for FOG Eigenfrequency Measurement

A low-cost approach was advanced to solve the problem of measuring fiber optic gyroscope (FOG) eigen frequency. Based on the principles of square wave modulation and demodulation in digital closed-loop FOG, the modulation of phase modulator had been done using fourfold eigen frequency square wave. Analysis of the demodulated signal obtained the relation between photoelectric detector output wave pattern and the frequency of modulation square wave, so the problem of eigen frequency measuring was transformed into the problem of pulse measuring and the complex programming software and expensive measuring devices was avoided. Experimental results show that the accuracy could be up to 0.075KHz when FOG eigen frequency was measured manually using this method.