Research On Tightly Coupled SINS/GPS Navigation Arithmetic Of Guided Bullet

The popularization of precision guided weapon has led to the birth and development of guided bullet,and also put forward higher requirements on the precision,rapidity and reliability of its own navigation equipment.Integrated navigation system can effectively realize the complementary advantages between different navigation systems and improve the positioning performance.SINS/GPS is the most classic and widely used implementation form among them.This paper uses guided bullets as the research target to conduct study on SINS/GPS tightly coupled algorithm,and its then verified and analyzed by simulation.This paper firstly introduces the composition and principle of SINS and deducts its posture,velocity,position calculation,equation and error equation in detail.And also introduces the principle of GPS positioning and speed measurement,the positioning and speed measurement equations are derived in detail,and the error characteristics are introduced.Based on this,the state equation and measurement equation are established for the compact combination model of guided bullets,and the filter model based on linear KF algorithm is presented.On the basis of completing the above work,this paper simulates the integrated navigation system based on linear KF algorithm.Firstly,the track generator is simulated according to the typal flying track of guided bullet,then the SINS and GPS that work along are analysed separately,and the simulation analysis of SINS/GPS tightly coupled model are also conducted.The results show that this method can effectively improve the divergence of SINS output error,but there are still some defects such as slow convergence speed and poor convergence performance.According to the problems above,considering the actual situation of tightly coupled of measurement equation often has nonlinear characteristics,this paper adopts DUKF algorithm to improve the filter,compared its computational complexity with normal UKF and conduct simulated analysis,then compare and analyze the output performance of DUKF and linear KF.Drug at the same time,considering rolling will happen the guided bullets flight and influence GPS receiver work,this paper also conducts simulated analysis of the performance of compact combination under interference,The results show that the filter can keep the error stable in a small range all the time,so as to ensure the rapidity and accuracy of the combined navigation equipment in the complex flight of the guided bullet.