The Research On The High Damping And Compass Alignment Technology Of SINS

In recent years,SINS has been widely used in the fields of aerospace and navigation with its unique advantages.However,the periodic oscillation problem of navigation parameter error has seriously affected the accuracy of INS.Therefore,SINS error suppression technology has become the key to ensure the accuracy of inertial navigation system.In addition,the result of initial alignment also directly affects the accuracy of navigation parameters.Therefore,this article focuses on the problems of SINS damping and initial alignment.To solve the problem of periodic oscillation of the parameter error,the more intuitive idea is to introduce a damping network into the system to ensure real-time availability of the solution information.The traditional damping method based on classical control theory is relatively mature.Therefore,the basic principle of traditional damping is elaborated,and the corresponding equations of the most commonly used external horizontal damping state of inertial navigation are also deduced.This dissertation focuses on the problem of high-channel damping of marine SINS.In the past research of marine inertial navigation system,the study of vertical channel was neglected.That is to say,the velocity and altitude information in were simplified.Due to the tight connection between the horizontal circuit and the natural channel,it is important to study the height channel in order to realize a three-channel marine inertial navigation system.Based on the instability of SINS channel,this paper designs a third-order damping loop based on classical control theory to dampen the velocity and altitude information and gives two kinds of system pole placement schemes from different angles.In this paper,the optimal parameter selection analysis and height error analysis of the third-order damping circuit are carried out.The influence of different error sources on the height error is discussed.Finally,the damping effect of the third-order damping circuit is verified through simulation.And the simulation also verified the validity of the conclusion on height error analysis.In addition,according to the influence of error input on the output,the frequency domain analysis of the system was also carried out.The effect of the frequency of the three error sources on the height error was analyzed by drawing a bode plot,which is a theory to discuss the effect of the abnormal value error on the altitude error basis.In view of the alignment error has a direct impact on navigation solution error,this paper studied the SINS initial alignment technology.The method of static compass alignment is aclassical method based on the control theory.In this paper,theoretical analysis and error analysis are carried out.Aiming at the problem of large azimuth misalignment,a time-varying parameter compass alignment method is proposed,the requirements of alignment time and alignment accuracy are all considered.Due to the limitation of static base alignment,another important research in this paper is moving base alignment.From the perspective of classical control theory,the method of compass alignment is used.In this paper,the carrier's uniform motion,uniform velocity motion and variable velocity motion process are considered.The errors caused by velocity and acceleration are equivalent to different forms of gyro drift and accelerometer zero.The influence of velocity and acceleration on the compass alignment result is analyzed from the perspective of frequency domain transfer function.On the basis of this,the method of dynamic compass alignment of Doppler Logging(DVL)-assisted strapdown inertial navigation system is proposed,including the compensation of error term and the design of acceleration compensation loop.Finally,the simulation results show the effectiveness of the proposed method.