Research On Key Technologies Of Multi-Station Passive Localization Based On TDOA And FDOA

Multi-station passive localization technology is generally employed in national defense and society because of its strengths of good concealment,long range and low cost.Especially in the field of electronic countermeasures,passive localization does not actively emit electromagnetic waves,but uses the electromagnetic waves emitted or reflected by the target to achieve the silent location of enemy UAV,radar and other facilities,which plays an increasingly important role in modern warfare.At present,the common location parameters in passive localization are:AOA,TDOA,FDOA and RSS.Based on the principle of several parameter positioning,this paper discusses the location system model,error source and positioning accuracy evaluation standard,intending to further advance the accuracy of emitter location and solve the influence of the receivers'position error on localization performance,and puts forward TDOA/RSS joint localization method and TDOA/FDOA joint localization algorithm for moving target when receivers' position error exists.The main contents of this paper are as follows:1)This paper introduces the research status of multi-station passive localization system and multi-station passive localization technology,expounds the basic principles,advantages and disadvantages of different parameter location methods,analyzes several common sources of location error,and gives the evaluation standard of localization accuracy.2)This paper introduces three classic TDOA location algorithms,including Chan algorithm,constrained weighted least squares algorithm and constrained total least squares algorithm.The basic location model of TDOA is given.The performance of these algorithms on estimating the position of target emitter is compared through simulation experiments,and the influence of the number of receiving stations on target positioning accuracy is studied.3)Aiming at the problem of high-precision localization of emitter,a joint localization algorithm based on TDOA and RSS measurements is proposed.By using Taylor series estimation method,the nonlinear equation constructed by TDOA and RSS measurements is linearized to further improve the positioning accuracy.Then,the maximum likelihood estimation method is proposed as a supplement for comparison,and the CRLB formula of the joint estimation method is derived.Simulation results show that the performance of the proposed joint localization algorithm is better than that of the conventional TDOA or RSS estimation methods.At the same time,the influence of the geometric position of unknown target in the receiving station on the positioning performance is analyzed.4)The location problem of moving target is discussed when the position error of receiving stations exists.Considering the three-dimensional localization scene,an improved Taylor series estimation method is proposed.TDOA and FDOA are used to calculate the position and velocity of the target and update the position of the receivers in the meantime,which reduces the influence of the position error of the receiver on the positioning accuracy.To reduce the number of iterations,a two-step method based on positioning error correction is used to estimate the initial position and velocity of the target.Simulation results show that the proposed algorithm has smaller RMSE and better performance than W-MDS algorithm,CTLS algorithm and TSWLS algorithm for both near-field and far-field sources,and it has better application value in the field of multi station passive localization.