Analysis And Realization Of Ring Laser Gyroscope SINS Data Acquisition Circuit

Laser gyro SINS is one of the main developing directions of the inertial navigation, which has great research value and broad application prospects. The development of embedded computer technology and digital signal processing technology has provided new ideas and methods for dither demodulation of laser gyro. This paper is researching how to providing high-quality inertial measurement data for navigation solution using new technology.This paper has first analyzed the operating principle of laser gyro. The measures of dither offset frequency have been taken to reduce the impact of latching error for laser gyro. And it will also introduce dithered signals, so the high-frequency vibration introduced by dither of original input data of laser gyro has been eliminated. In this paper, the method of digital filtering has been used to eliminate dither of laser gyro and high frequency measurement noise caused by other factors.As FIR filter can satisfy the strict requirements of system for amplitude and phase to avoid temperature drift and random noise and other issues of analog filter, FIR filter has been used to eliminate dither and other interfering signals in this paper. Using DA algorithm, multiply operation is converted to look-up table structure. DA algorithm can realize a number of multiply operations efficiently, it has more advantages than using multiplier to design FIR filter both in speed and resources. The main functional circuits such as counters, latches, filters used in Data Acquisition Circuit and digital signal processing algorithms have been realized in FPGA. The design complies with the guiding principles of FPGA and achieves the optimal balance between speed and area.In this paper, PC/104 system has been used as control module, and whose driver under DOS operation system has been written. The data has been displayed by interrupt. In order to further verify the correctness of acquisition circuit, static experiment has been down using the inertial navigation system. And the output data of gyroscope have been conducted power spectral density analysis. The results further prove the correctness of the circuit system.