Research On FOG North Finding System And Anti-interference Technology

Fiber optic gyro north finder is a kind of inertial device used to measure the geographical true north direction, based on the principle of the inertial technology. It don't rely on external environment information.And it can work long hours, find the true north direction rapidly and accurately.It's widely used in military and civil fields.The precision of the fiber optic gyro north finder is mainly affected by two aspects: the precision of fiber optic gyro and north decoding algorithm. This paper is about the research of fiber optic gyro output signal filtering methods and north finding plans. This paper mainly completed the following works:First,this paper introduced the optical fiber gyro north find system hardware composition,the working principle of optical fiber gyro and it's north-finding methods.Second, error source and noise characteristic of FOG north finder are analyzed in detail.And then the Allan variance analysis method are used to establish optical fiber gyro error model.Third, the paper introduces the main principle of wavelet analysis, emphatically introduces the wavelet threshold de-noising algorithm based on the characteristics of fiber optic gyro output signal. The paper improves the traditional wavelet threshold de-noising algorithm. Some programs require short north-finding time,and in order to meet this kind of requirements, this paper introduces another de-noising algorithm, lifting wavelet threshold de-noising algorithm, which is faster than the wavelet threshold de-noising in calculation,increases the speed of the whole process of the north-finding system, and this algorithm can independently complete signal de-noising.Finally, using fiber optic gyro output data which were collected in the lab to finish the experiments. The results shows that the data processing algorithm can largely improve the precision and speed of fiber optic gyro north finding system .