Passive Location Based On Time Difference Of Arrival And Frequency Difference Of Arrival

The use of active devices such as radars to estimate the location of the target belongs to the range of active positioning,one of the disadvantages of active positioning is that it vulnerable to be subject to anti-radiation strikes or electronic interference,thus the security of the system cannot be guaranteed,while the emergence of passive positioning technology has solved this problem well.The main difference between passive positioning technology and active positioning technology is that it does not need to transmit signals itself,and it is a technology that directly uses the signals emitted or reflected by the target to obtain the target position.Its main principle is to by using multiple receiving station with known locations to common receive signals transmitted or the reflected from a target,extract the observed parameters which can be used to obtain the target position parameters,build these observations into nonlinear algebraic equations about the target location,and to solve the effective estimate of the target position,so as to realize target orientation.This thesis studies the passive positioning method based on the combination of time differences of arrival(TDOA)and frequency differences of arrival(FDOA).The paper studies the basic principles of TDOA and FDOA joint positioning,and analyzes and simulates several common methods of TDOA and FDOA joint positioning in detail,including two-step weighted least squares(TSWLS),total least squares(TLS)based on singular value decomposition,and constrained total least squares(CTLS)method.On the basis of existing theories and methods,this paper proposes improved iterative constrained weighted least squares method,which is a iterative constrained weighted least squares method based on sliding window noise reduction processing.This method transforms the positioning problem into a weighted least squares solution problem of obtaining deviations under constraints by constructing the pseudo-linear equations of TDOA and FDOA of the moving target source,and then through iterative method combined with sliding window noise reduction processing to obtain the moving target source position and speed.Through the analysis and simulation of this method,it is shown that the iterative constraint weighted least squares method based on sliding window noise reduction processing proposed in this paper can effectively improve the positioning accuracy,and has certain reference value for solving the problem of moving target source positioning.