Research On Target Tracking Algorithm Based On Three-satellite Passive Fusion Positioning System

Satellite passive positioning technology is one of the important components of electronic countermeasures technology.It has the advantages of long detection distance,wide monitoring range,not being affected by regional borders,and good concealment performance.In recent years,the positioning and tracking of mobile radiation source targets has become a hot issue in the field of spaceborne positioning.The traditional time difference and frequency difference positioning method for high-speed maneuvering target positioning often introduces positioning errors caused by unknown target speed,which leads to a decrease in accuracy.On the other hand,high-speed maneuvering targets are often located at high altitudes rather than on the surface.Under this premise,the positioning accuracy of traditional single positioning system algorithms based on elevation estimation will be greatly reduced.In response to these problems,this paper proposes a three-satellite TDOAFDOA-DOA fusion positioning method.Based on the traditional three-satellite time difference and frequency difference positioning system,a one-dimensional interferometer device is installed on the host satellite to obtain the direction of arrival information of the radiation source.This information is fused with the three-satellite time difference and frequency difference information to realize highprecision positioning of mobile targets with unknown elevations.This article focuses on the research on the positioning of maneuvering targets in the threesatellite fusion positioning system.The main contents include:(1)The three-satellite time difference and frequency difference direction finding fusion positioning system is studied.First,the mathematical model of the positioning system is established based on the coordinate conversion between multiple coordinate systems,and based on the positioning model,the fusion positioning algorithm and the traditional single system satellite positioning are established.The performance is compared and analyzed.By comparing the GDOP diagrams of the algorithm positioning errors under different elevation errors,the distribution of the positioning errors of each algorithm is analyzed,and the superiority of the fusion positioning algorithm applied to the target positioning problem without elevation constraints is demonstrated.(2)Aiming at the highly nonlinear characteristics of the three-satellite fusion positioning system,an improved iterative extended Kalman filter algorithm is proposed to achieve high-precision tracking of moving targets.The algorithm first uses the time difference and direction finding observation information to estimate the initial position of the target tracking,and then adds multiple iterations to the traditional extended Kalman filter state update process.Compared with the traditional extended Kalman filter algorithm,the algorithm has a smaller Linearize the high-order term to cut off the error,so as to achieve the goal of improving target tracking accuracy and convergence speed.(3)Combining the interactive multi-model method and the particle filter method,the IMMIEKPF algorithm based on the three-satellite fusion positioning system is proposed.The algorithm improves the IMM-PF algorithm,and uses the improved IEKF algorithm to generate its importance density function,which fully combines the observational new information,so that the generated samples are closer to the real sampling samples,which greatly improves the tracking accuracy of the algorithm.The article compares several traditional tracking methods with the method in this paper,and qualitatively analyzes the tracking effect and error of each algorithm.(4)Built a comprehensive simulation system for spaceborne electronic reconnaissance based on STK and QT.The system can simulate the real electromagnetic environment,and can perform simulation analysis and error evaluation on multiple positioning systems such as single-satellite interferometer positioning,dual-satellite time-frequency difference positioning,three-satellite timedifference positioning,and multi-satellite fusion system positioning.The simulation system is used to simulate the performance of the method proposed in this paper,and then to evaluate the correctness and rationality of the designed satellite system and positioning algorithm.