Research On The Technique Of Integrated Calibration Of Inertial Navigation System

The inertial navigation is the important one kind of navigation techniques,which can independently provide the information of position,velocity and attitude of the carriers.And in the whole process,the system will not transmit any signal,with this secure character,it is extensively accepted and applied,especially in the areas of aeronautics,astronautics and sailings.However,because of the IMU errors,the navigation informations output by the system will cause the error divergence over time.In order to maintain the accuracy,during the working time,we should estimate the error at regular time and compensate the system with which,and meanwhile,we will reset the positon,velocity and azimuth.This technique is so-called integrated calibration.And based on this idea,this paper will research the algorithm of integrated calibration of gimbaled inertial navigation system and strapdown inertial navigation system.At the beginning,this paper introduces the fundamental knowledge and the inertial navigation principle,deduce and build the error equation,it is proved that the error existing in the accelerometers and gyroscopes will cause the spread of navigation information errors,at last,we testify the conclusion with computer simulations.In the OEPQ coordinate,we dudece the integrated calibration algorithm of gimbaled inertial navigation system.Based on the position provided by GPS and the azimuth provided by CNS,builing the relationship of system position errors and attitude angle errors,and the relationship of attitude angle errors and gyroscope drift,and we put forword the algorithm in the OEPQ coordinate suitable with SINS.By analyzing this algorithm,we find the limitation for the ship movement.At last,we build the equations in the inertial coordinate,and prove it with simulations,which can improve the application of integrated calibration.Especially,for the space stabilized inertial navigation system widely applied in strategic weapons,we design the mechanical configuration scheme,build the error model and deduce the error equations.Base on which,we conclude that the gyro drift can cause the spread of errors,and we put forward the two-point method utilized position provided by GPS and the one-point method utilized position and azimuth provided by GPS and CNS.At last,we prove its correction with simulationThe last part in this paper,we design the calibration algorithm based on Kalman filters.Establishing the error models of gimbaled inertial navigation system,building state equations taking platform angle errors and gyro drifts as state elements,building observation equationstaking position errors and azimuth errors as observation elements,and utilizing the Kalman filters to estimate the gyro drifts and compensate the system.As for the strapdown inertial navigation system,we establish the error equations combining Doppler Velocity Log,building the observation equations taking velocity errors as observation elements,estimating gyro drifts of SINS and compensating the system.And finally verify the theoretical research on the design by the use of simulation experiments.