Research On Rapid Transfer Alignment Technology Of Airborne Strapdown Inertial Navigation Systems

Airborne missiles are the main weapons in modern warfare and play an important role in military defense and offensives in theaters.Strapdown Inertial Navigation System(SINS)is widely used in various airborne weapons because of its simple structure and high reliability.Transfer alignment is one of the key technologies of inertial navigation,and its rapidity and accuracy are the important guarantees that airborne missiles can accurately hit.The theme of this paper is the rapid transfer alignment technology of airborne SINS.Transfer alignment model,error analysis and compensation of transfer alignment,and adaptive filtering method are researched in the paper aiming to improve the speed and precision of transfer alignment.The main content of the paper is as follows:(1)The common coordinate system of SINS and its conversion relationship are established.The two transfer alignment models,Φ-angle error model and Φm-angle error model,are compared and analyzed,and the error equations and consistency of the two models are theoretically derived.The Kalman filter equations for angular rate matching,velocity matching,attitude matching,and Velocity plus Attitude matching are given.(2)The error factors and compensation methods of rapid transfer alignment are analyzed.The error model of inertial device and the second-order Markov model of deflection are established respectively with the corresponding compensation methods.The principle of the lever arm effect is analyzed,and the compensation of the rigid lever arm effect is realized by the calculation compensation method.By analyzing the mechanism of lever arm vector change caused by deflection,a compensation method for dynamic lever arm effect is proposed.In addition,the effectiveness of each error factor compensation method is verified through simulation.(3)The Sage-Husa adaptive filtering and its simplified form are analyzed.In order to solve the problem that Sage-Husa adaptive filtering is extremely sensitive to the initial value of the filter,an improved Sage-Husa adaptive incremental Kalman filtering is proposed.By introducing a fading factor to adjust the one-step forecast error variance matrix or gain matrix,the filtered value can track the change of the current value,and at the same time improve the filter measurement equation to eliminate the systematic error introduced into the measurement equation.Simulation analysis verifies that the improved Sage-Husa adaptive filtering is superior to the other two methods in both alignment speed and precision.(4)The semi-physical simulation of the above rapid transfer alignment method is carried out using van test data.The simulation results verify the effectiveness of the rapid transfer alignment adaptive filtering algorithm from the transfer alignment accuracy and navigation landing point accuracy,laying a solid foundation for practical engineering applications.