Research On The Key Technology Of Disassembly-free Calibration Method For Missile-borne Sins

The accuracy of missile-board SINS is one of the key factors which affect missile strike capability.However,the error parameters of Inertial Measurement Unit(IMU)in missile-borne SINS change during the process of storage.Since the errors of IMU is one of the main errors of SINS,the accuracy of missile declines when IMU is compensated by parameters calibrated before leaving the factory.Therefore,recalibration is necessary to ensure the accuracy of IMU.Traditional calibration method is to disassemble the IMU from the projectile and calibrate the IMU on a three-axis turntable of high accuracy,which cost a large number of labor and resources.Besides,the disassembly process might lead to uncertain installation error.This thesis puts forward a disassembly-free calibration method for the missile-borne SINS,which is able to calibrate the IMU without taking it off the projectile.The method can decrease the cost and shorten the time of calibration,which has important significance on improving the quick reaction capability of weapon system.The main contents are as follows:1.The basic principle of inertial navigation is presented.Based on error models of fibre-optic gyroscope and quartz accelerometer in IMU,the error equations of the missile-borne SINS is established under the north-up-east coordinate system.2.GPS and master SINS of high accuracy are utilized to provide velocity,attitude,specific force and angular rate observation information.The system equations of velocity and attitude match,specific force match and angular rate match are educed.The principle of Kalman filter and east-square estimation is researched.Based on system model of three match methods and filter methods,the theoretic framework of disassembly-free calibration method is elaborated.3.The observable degree analysis method based on PWCS and singular value theory is researched.The observability analysis of different maneuvers and match methods has been performed to evaluate the estimable level of each system state.Observability analysis shows that all 24 parameters of IMU are observable stimulated by turning,pitching and rolling maneuvering.Furthermore,the simulation program of the SINS has been compiled,and simulations have been performed to test the proposed calibration method.Computer simulations show that high precision of IMU error parameters is achieved by disassembly-free calibration method.Considering the maneuverability of missile launching vehicle,a proper path is designed according to the result of observability analysis and stimulation.4.The experiment is carried out on the three-axis turntable of high accuracy using medium low precision fiber-optic IMU.Different maneuvers of the missile launching vehicle are simulated by corresponding movements of the three-axis turntable,while using the data of turntable as the main SINS data.The IMU is calibrated according to the disassembly-free calibration procedures,and the calibration results with both traditional method and the proposed method are compared.Besides,the accuracy of positioning after 900s inertial navigation is compared with inertial sensors compensated by traditional calibration and disassembly-free calibration,which proves the effectiveness and engineering feasibility of the proposed calibration method.