Research On Direct Position Determination Technology For Single Moving Station

In modern warfare,passive location is one of the most important topics in electronic warfare.It can realize the effective detection and positioning of the target in a particular area without transmitting electromagnetic pulse,and fully display the advantage status of the battlefield,and the passive location technology of the single station is a hot topic in the passive positioning technology.The traditional passive location method belongs to the two step positioning system,namely,"parameter estimation & positioning solution",but the system also has some problems.From the point of view of information theory,from the original data received to the final result,each step of processing will be difficult to avoid resulting in certain information loss and lead to positioning.The accuracy is affected,and it is difficult to get the best estimation result.Direct Position Determination(DPD)technology is a new passive location technology proposed in recent years.Its basic idea is to get the location of the target radiation directly from the received data,and combine the parameter estimation with the positioning solution to a location model,which avoids the traditional two step positioning method.The information loss improves the positioning accuracy.Therefore,based on the single station location model,the DPD algorithm is introduced into the model,and the location model under different scenes is constructed in the light of different measurements such as Doppler and time delay.The research work is carried out in three aspects: the single station DPD positioning model,the DPD location model of the single station and the search optimization algorithm under the condition of non-array signal.The main contents and results of the paper are as follows:1.In the process of target location by using a single station to receive the source signal,the traditional two step location algorithm will result in information loss,which leads to the problem of lack of estimation accuracy.A single station DPD only using Doppler,only time delay and joint delay and Doppler's non-arrayed signal motion is proposed.Algorithm.The algorithm uses the minimum mean square error(Minimum Mean Square Error,MMSE)estimation model to construct the cost function and obtain the conjugate matrix containing the location information of the radiation source.Then,the maximum eigenvalue of the conjugate matrix is obtained by the eigenvalue decomposition of the unknown signal and the known signal.Finally,the two-dimensional grid type spatial index is obtained.The estimation of the location of the radiation source.At the same time,the paper also derives the corresponding Cramer-Rao Lower Bounds(CRLB),and analyzes the location performance of the algorithm under the error of Doppler and time delay measurement and the computation of the algorithm.The theoretical analysis and simulation experiments show that the proposed location algorithm can approximate the target location error of CRLB,and compared with the two step positioning algorithm,it has better positioning accuracy.2.To solve the problem of insufficient directivity of spatial signal by single array element,multiple array elements are used to obtain the target information of radiation source.Based on the DPD algorithm of non-array signal motion single station,and combining the algorithm idea of array signal processing,a motion single station DPD algorithm based on array signal is proposed..At the same time,this paper also derives the CRLB of the estimated parameters,and analyzes the location performance of the algorithm and the computational complexity of the algorithm in the case of Doppler and delay measurement.Theoretical analysis and computer simulation results show the effectiveness and superiority of the proposed location algorithm.3.Aiming at the problem of too much computation when traditional grid search methods are applied to DPD algorithm,this paper proposes an optimization algorithm combined with multiple search methods.The algorithm first uses the DOA direction finding cross location to determine a rough search range,then uses multiple search algorithms in the range,and nested the mountain climbing algorithm in each search.By solving the maximum eigenvalue of the conjugate matrix containing the target location information,the corresponding position estimation is obtained.Besides,the time complexity of the new algorithm is also analyzed.The theoretical analysis and simulation experiments show that the search accuracy of the algorithm is close to the traditional grid algorithm,and the global optimal solution of the approximate MMSE estimator can be obtained,and the computational complexity of the algorithm is greatly reduced.