Research On Signal Processing Algorithm Of Mechanically Dithered Ring Laser Gyroscope

The general method to remove the dither noise of the Mechanically Dithered Ring Laser Gyroscope(MDRLG) at present is to design a Finite Impulse Response(FIR) lowpass digital filter according to the lowpass filter's frequency select function. This method can also remove the random noise as well as the high frequency noise and then detect the inertial angular rate. But the order and the delay time of the FIR filter will be much high to achieve well performance.In order to reduce the drawback of the FIR filter, a new method of dither signal remover of MDRLG utilizing a Adaptive Notch Filter (ANF) with constrained poles and zeros as a pre-filter in series with a lower order FIR lowpass filter is introduced. Actually the ANF attenuate part of the dither noise, and the lower order FIR filter removed the others. By using ANF we reduced the order and the delay time of the FIR filter, test and experiments'results show that the outputs adopted this method has a less variance, and the computation expense is low enough to be used in the Strapdown Inertial Navigation System (SINS).In the end, the algorithm is implemented on the TMS320C3x Digital Signal Processor. The static precision of a MDRLG, the sum impulses of a rotated MDRLG, the output average and the trace character between the notch frequency and the horizontal and vertical dither frequency on the vibration test system are tested. Results show that the new method has a good performance and can be used in SINS with MDRLG.