Research On The Methods For Improving The Accuracy Of Laser Gyro SINS In Vibration Environment

In order to improve the accuracy and cost-effectiveness ratio of the medium-rangeor long-range ballistic missile (MRBM or IRBM), it needs many high-performance,low-cost strapdown inertial navigation systems. In this regard, the ring laser gyrostrapdown inertial navigation system (RLG-SINS) has unique advantages. However,detail research on RLG-SINS which works in vibration environment has not been donein domestic. In this paper, many works in terms of error model, calibrationcompensation technology and vibration error have been done, aiming at studying themethods to raise the precision of the systems under vibration condition.Firstly, the principle of SINS was introduced briefly, navigation system errorequation was derived, and the propagation characteristics of SINS in linear vibrationenvironment were studied by simulation and compared with the static base condition.Especially, the influence of accelerometer quadratic error was analyzed in detail.Secondly, the error model of inertial sensors, including the accelerometer quadraticerror, was established, and the body frame was restricted to avoid the coupling betweenthe error parameters. According to the error model of the sensors and navigation errorequation, a31-order error model of the RLG-SINS was established, and the simulationshows that the new error model has better accuracy than the traditional error model byan order of magnitude.Thirdly, a33-order calibration model including the accelerometer quadratic errorwas designed using the technology of closed-loop Kalman filtering. The observabilityand observable degree of18rotating positions were analyzed on the basis of Piece WiseConstant System (PWCS) and singular value decomposition (SVD) theory. Thesimulation proves the feasibility of the proposed systematic calibration method. Themethod can calibrate many error parameters, and have a high calibration precisionmeeting the requirements of navigation grade system.Finally, the dynamic characteristics of the system were studied through a series ofvibration experiments. Experiments show that the damper can effectively isolate thehigh-frequency vibration components that affect the system badly, but due to theinfluence of the damper resonance, the vibration below100Hz has a certain degree ofamplification, which will result in conical drift. So, coning compensation algorithm wasstudied by simulation and experiments. The results show that coning compensation caneffectively reduce drift and improve the accuracy of the system in vibrationenvironment.