Research On Integrated Calibration Technology Of Strapdown Inertial Navigation System

Strapdown Inertial Navigation System can be simply referred to as SINS,all of its inertial devices(gyroscopes and accelerometers)directly loaded on the carrier,not as a platform inertial navigation system that there is physical platform inertia device isolated from the carrier angular motion.Compared with the inertial navigation system,the strapdown inertial navigation system has a different way to be made,but its basic principle is the same.And in the Inertial Navigation System(INS),the problem that the navigation parameter information output by the inertial navigation system gradually increases with time due to the inertia device error also exists in the strapdown inertial navigation system.In order to obtain the high precision navigation output information,it is necessary to measure and correct the inertia device mainly gyro error,and to adjust the navigation parameters such as position information,velocity information and azimuth information.In general,the above description is usually referred to as a comprehensive correction technology,and this paper is to study the integrated strapdown inertial navigation system correction technology.In this paper,the main error is modeled on the basis of the SINS principle,and then it is pointed out that the inertial device error is the most important error source,which is caused by the gyros and the accelerometers.By taking qualitative and simulation analysis.the error caused by gyros drift is far greater than the accelerometer caused.On the basis of the above,this paper presents a method which is different from the traditional comprehensive calibration(by means of position information or position and azimuth information),that is,a comprehensive correction method based on velocity information.The angular error model is used to establish the relationship between drift angle and velocity error and gyro drift.The velocity error is used to estimate gyro drift,and the relationship between velocity error and heading error is established by the relationship between azimuth error and heading.Finally,when the gyro drift is corrected,the system navigation parameters are reset.In order to obtain SINS with higher precision,a Kalman filter-based synthesis correction method is studied considering the gyro random drift and the interference error of the outer reference information.Based on the extended kalman filtering,the drift angle and gyro drift are seen as the state variables,and the error of position is seen as the measurement variables.With them,the state and the measurement equation are established and then the gyro drift is estimated and corrected.Aiming at the problem of the error of the outer velocity,the velocity error model of the Doppler velocity measurement system is analyzed and established.The state and measurement equation of the strapdown inertial navigation system are established by combining the error model of SINS and the velocity error model of the Doppler.Through the analysis of the filter correction and simulation studies,the blending correction method is more accurate.