The Research On Dynamic Errors And Long-term Parameter Stability Of RLG SINS

It tends to have more and more information warfare and remote combat in modern warfare, and at present, high-precision ring laser gyro strapdown inertial navigation system(RLG SINS) is the key system to guarantee high strike accuracy of weapons and equipments when there is external electromagnetic interference. However, on one hand, the research on dynamic errors of RLG SINS is not sufficient; on the other hand, there are few public published literatures about the research on its long-term parameter stability. These two factors make the precision of RLG SINS dramatically degraded under high dynamic environment and long-term application. In this paper, the dynamic errors and long-term parameter stability of RLG SINS were studied through a series of theoretical and experimental research, aiming at finding methods to improve the precision and long-term parameter stability of RLG SINS under high dynamic environment.First of all, the basic principle of RLG SINS was explained, the common-used basic parameters and coordinate systems were defined, and according to the characteristics of different error parameters, the component error model was established. Aiming at the RLG SINS applied under high dynamic environment, the error effect of two dynamic errors, quadratic term error of accelerometers and inner lever arm parameters, were analyzed by simulation, which illustrated the necessity to put these two dynamic errors into error model under high dynamic environment.Secondly, additionally considering quadratic term error of accelerometers and inner lever arm parameters, a 36-dimension Kalman filter was designed. According to the way of error stimulation, an appropriate calibration procedure was designed, and the effectiveness of the procedure was proved through observability analysis. Based on the designed 36-dimension Kalman filter and calibration procedure, a new systematic calibration method was proposed, and the effectiveness of the calibration method was verified through simulation and experiment.Finally, based on long-term parameter calibration experiment, different error parameters' stability of two sample systems was analyzed mathematically. Choosing normalized triple standard deviation as the index, the stability of different parameters and systems was sequenced, and the stability of two systems was compared. Based on the mathematical analysis results, the possible influence factors of different error parameters were discussed preliminarily. The possible influence factors of RLG zero bias' stability caused by blocking threshold's instability were studied emphatically. In order to further discuss RLG zero bias' drifts caused by introducing surface imperfection, based on distinguishing different scattering effect caused by different surface spatial wavelength, the conception of large and small scale roughness was introduced, and the scattering model of surface roughness was improved. Based on that, the theoretical calculation model of the oblique incidence multilayer's optical characteristics when considering surface roughness and its spatial wavelength was deduced. According to effective medium theory, the effectiveness of the model was verified by numerical simulation method.