Research On Passive Localization Technology Based On Distance Measurement Using Wireless Sensor Network

With the rapid development of wireless sensor network,the passive target localization technique plays an increasingly important role in electronic reconnaissance,electromagnetic frequency spectrum management,rescue,travel and other fields.In the past decades,many scholars domestic and overseas have done a lot of research results on target localization analysis based on TOA parameter.However,in the asynchronous network without of clock synchronization between sensors and located target,the method to accurately analyze the target position with TOA parameter information measured by multiple localization sensors still remains to be further and deeply studied.On the other hand,it is imperative to find out a direct localization method of moving target based on a single station because of the disadvantages of perception data aggregation and transmission in distributed cooperative network.In view of the above problems,this paper has made a series of analytical solutions as follows:For the single-target distributed cooperative localization scenario,with the distributed TOA parameter measurements as input,an accurate SDR analysis method is proposed in this paper,so as to solve the TOA localization problem with unknown initial transmission time.By establishing a non-convex WLS minimization problem,the algorithms can estimate the target localization,velocity and distance deviation caused by unknown initial transmission time jointly,and then the SDR algorithm is applied to solve the problem.The simulation results show that the proposed method can achieve the accuracy of CRLB closely,despite there is error approximation and relaxation treatment in the solution process.Then,this paper extends the above method practically,and for an application scenario where the sensor position itself has error,the SDR analytical algorithm for target passive localization is studied,which can effectively resist the deterioration effect caused by the sensor position error itself.This algorithm ingeniously introduces the statistical information of sensor position error,and deduces more practical new algorithms for single static target and single moving target respectively,and then infers the lower bound CRLB of CramerRao theory in two cases.The computer simulation analysis shows that the proposed algorithm can well eliminate the analytical deterioration caused by the sensor position error,and can achieve the accuracy of CRLB for both the static target position information and the moving target position and velocity information,and this fully proves the effectiveness of the proposed algorithm and its good application prospect in practical scenarios.Furthermore,this paper further complicates the above algorithm,and in view of the complex practical application scenarios where there are errors in the sensor position and in the clock synchronization between sensors,a multi-target-oriented SDR analysis algorithm for TOA measurement is studied,and this algorithm can be applied to multiple static target scenarios and multiple moving target scenarios.The core idea and advantage of this algorithm include introducing the position error statistics information of sensors themselves and the clock synchronization error statistics information between sensors,taking full advantage of the assumption that the TOA measurement information of different targets contains the same sensor position error and clock synchronization error between sensors,so that the proposed algorithm can effectively resist the deterioration effect caused by sensor position error and clock synchronization error between sensors.Aiming at the inherent problem of central perception data aggregation and transmission in distributed cooperative passive localization system,a method of direct localization of moving target based on a single station is proposed in this paper.The linear antenna array is arranged in the monitoring station,and then an idea of inverse synthetic aperture is introduced,and later the size of monitoring aperture is increased equivalently by making full use of the moving characteristics of the located target,and the maximum likelihood estimation solution is obtained by exhaustive search of cost function relative to the position and velocity of the target.The proposed method only relies on a single fixed monitoring station,which effectively avoids the aggregation problem of monitoring data centers faced by traditional multi-station cooperative localization methods and avoids the requirement of synthetic aperture idea for monitoring station movement.The computer simulation shows the feasibility and performance of the proposed method.To sum up,this paper makes a study aiming at the SDR analytical algorithm of passive target localization based on TOA measurement and the direct localization algorithm of inverse synthetic aperture of moving target based on single station,and the methods studied are all based on the problems in practical application.The computer simulation verifies that the proposed algorithm is effective in eliminating all kinds of complex system errors and avoiding the aggregation problem of monitoring data centers,and has a good practical application prospect.