The Study Of North-finder Techniques Based On FOG

Fiber Optical Gyroscope (FOG) north-finder is a kind of inertia devices applied for measuring the true north bearing. The measurement can be applied in all-weather fleetly and without relying on information of the external environment. It has been used widely in national defense and economy construction in last decades. Compared with conventional mechanical gyroscope, FOG's merits such as high sensitivity, short warm-up time, light weight, long operating life, large dynamic range and low price, make it particularly appropriate for north-finder which needs miniaturization, high-accuracy and inexpensive.This work studied filtering methods for FOG signal, the application and designing of FOG north-finder.First of all, several solutions of north-finder were introduced. By analyzing the performances, the advantages and disadvantages of different north-finder solutions were comparedNext, error source and noise characteristic of FOG were analyzed in detail.Then, The principles of wavelet analysis were presented in details. Base on the studying on characteristics of FOG signal, wavelet de-noising method was given, and experiments on real FOG signal were processed. The results showed that the wavelet analysis on time-frequency field has good performance, and can effectively restrain random noise in FOG signal.Finally, total designing of FOG north-finder was given.The FOG north-fider method was based on DSP, use FPGA to construct the digital circuit of FOG and realized analog circuit design at the same time. The circuit of steady speed control of turntable and software designing for FOG north-finder were introduced at last.