SINS Dither Sampling And Preprocessing Gyro

At present, Laser Strap-down Inertial Navigation System has become an importantresearch field for China’s national defense science and technology, it has wide applicationprospects and great research value. And the RLG’s development and application has bring anew technology revolution to the traditional inertial technology. Now in the LSINS of lasergyro data acquisition and preprocessing, the main difficulty and emphasis is to ensure thatthe signal acquisition in the number of lost, and can be good dither bias signal filtering forthe RLG.First of all, this paper takes the NAV Technology Co., Ltd company’s original LSINSas the research background. On the basis of grasp the overall LSINS to divide the FPGA andDSP functions, propose a new kind implementation scheme for Laser Strapdown Inertialnavigation data acquisition and preprocessing based on Nios Ⅱ soft core. ReplacedFPGA+DSP system structure use the transplant Nios Ⅱ soft core FPGA chip EP1C12+ARM,let more superior performance of FPGA to complete the system all the signal acquisitionand preprocessing, while DSP only for navigation solution. After completion of the gyrosignal phase demodulation and reversible counting work inside the FPGA, then completethree road laser gyro signal filtering pretreatment in the Nios Ⅱ soft core.Secondly, design a high order FIR filter according to the RLG dither biascharacteristics. But due to the high order FIR filter had a big delay problem, this paper putsforward a new filtering method, use a adaptive notch filter with constrained poles and zeroto the RLG preliminary filtering, then through a low order FIR filter to further removedithering partial frequency signal.Finally, according to the two filter through Matlab on static LSINS original datafiltering, through the analysis and comparison of two kinds of filters to judge two kinds offilter characteristic and difference. And through the sports car experiment and analysis filterused in the system of RLG signal acquisition and preprocessing work to validate the designof the two kinds of filter can very good play a filtering jitter partial frequency signal role.And that the call configuration Nios Ⅱ soft core can also is very good for the completion ofthe LSINS signal acquisition and preprocessing work, has achieved the design requirements.After the experiment and sufficient data analysis comparison, proved that the scheme forLaser Strapdown Inertial navigation data acquisition and preprocessing has the advantagesof low cost, reliable operation, high precision, high speed etc.