Direct Target Determination Algorithm Based On TDOA And FDOA

In modern war,target location technology has great significance.Compared with active location,passive location are widely concerned because of its quality of concealment.Traditional approaches are based on two step.In the first step,the receivers estimate the location parameters and in the second step,these parameters are used for estimating target moving states.In the recent years,the DPD algorithm was proposed.Compared with the conventional two-step method,DPD directly extracts target moving state information from received signals and has better estimation accuracy.In this paper,we study DPD deeply and get some interesting research results.The contributions are summarized as follows.1.The Particle Swarm Optimization algorithm is used to search the maximal value of DPD cost functions,which reduces the computational load of DPD and make it more practical.Compared with two-step method,the estimation accuracy of DPD is higher,but it has expensive computational load.In order to resolve this problem,we use the Particle Swarm Optimization algorithm to extract the optimal value of DPD cost functions.In comparison to the traditional grid search method,this way can reduce the computational load.2.We use the signal model of DPD in TDOA location and propose the coherent algorithm for eliminating ambiguous TDOAs.The traditional methods for eliminating false TDOAs usually use the information of TDOA,DOA,etc.In this paper,a coherent algorithm for the stationary transmitter and receivers is proposed and the algorithm’s capability for reducing ambiguous TDOAs is analyzed.The coherent algorithm can eliminate false TDOAs by making use of the phase information of the received signals in comparison to the conventional approaches.Simulation results show that the effects of eliminating ambiguous TDOAs are influenced by the carrier frequency and PRF of signals.3.We use the idea of DPD in target tracking and propose the DTT algorithm.Traditional target tracking methods address the target tracking problem by using the measuring information,such as TDOA,AOA,FDOA,etc.In this paper,DTT for the target which moves at constant speed and in a straight line is proposed.Compared with conventional algorithms,this method can directly extract the target’s moving track information from the received signals.Simulation results show that DTT have the ability to estimate target moving states.