Gyro sample frequency and noise restraint methods in a high-precision laser INS

Based on the characteristics of laser gyro's high bandwidth and digital output, two basic problems in laser gyro digital signal processing are put forward, i. e. rational sampling frequency and anti-aliasing filter. The laser gyro spectrum characteristics in domestic high-precision laser strapdown inertial navigation are analyzed, and it is found that there are some fixed frequency jamming signals in the laser gyro output at 2000 Hz sampling frequency. A noise restraint method is put forward by gradually increasing sampling frequency to locate spectrum peak position, and the frequency calculation formulas are given. It is verified that there are 3 times and 5 times of dithering frequency interference signals in laser gyro output signal by using these formulas. The domestic high-precision laser gyro's reasonable minimum sampling frequency is given, which should be 4500 Hz at least. In order to solve the problem of anti-aliasing filter, an oversampling technology should be used to reduce the power density of the laser gyro in frequency field. Meanwhile the low-pass filter should be employed to restrain noises and improve the laser gyro's accuracy.