Research Of Calibration Based On Differential GPS For Systematic Error Of SINS

This paper is mainly about the calibration method research of vehicle carried strapdown inertial system(SINS).It's well known that inertial components of SINS have the defect that errors will accumulate as time goes on.Besides,when the system is at work,it will suffer the motion and shock of the vehicle,and influence of temperature.Characteristics of inertial components and the influence from the environment will result in the reduction of the accuracy of navigation inevitably after working in a period of time,so it is necessary to calibrate the inertial components.The differential GPS with high precision is used to help to calibrate SINS.First,the basic principles of inertial navigation system are introduced,the calculation of the attitude matrix,station and velocity updating are derived,the system's main error source and characteristics of inertial navigation systems is analyzed,error model is established,and the impact of these error terms to the system is analyzed.Secondly,the derivation and calculation standard Kalman Filter are introduced.Then state equation of SINS is established,position and velocity is chosen to be observable variables to establish the observable equation,and the equation is discretized.Then,it's necessary to analyze the observability of SINS.Observable analysis theories are introduced,and methods such as PWCS and SVD are introduced in detail.Incentives of the systematic errors are analyzed,and in order to incent more systematic errors,trajectory generator including three calibration paths is designed,which takes the possibility of operation into consideration.PWCS and SVD are used to analyze the observability of different paths.Finally,the simulation is conducted to parameters of different paths through adjusting the parameters of Kalman filter,and the results are analyzed to show that the calibration method is feasible theoretically to some extent.