| In passive detection system, the multipath signals and the separation of the multipathsignals and the direct wave signal is a key technical aspects, it directly affects the targetdetection results，Current solutions are generally suppressing the direct wave mixing inmultipath signal to retain the multipath signal. Commonly used techniques can bedivided into airspace methods and time-domain methods.In this paper, one of the key technologies—multi-path signal separation wasdiscussed in theoretical and simulation. Finding a feasible technical solution and achievinga good experimental results based on time domain.Firstly, the LMS (minimum mean square) algorithm based on Winner filtering theoryand its improved algorithm and RLS algorithm based on least squares was introduced andsimulated. Secondly, the performance of these algorithm in convergence rate, steady-stateoffset, the tracking capacity of time-varying signal is compared under the sameexperimental conditions. Analyzed the step size, forgetting factor, signal-to-noise ratio, thesignal carrier frequency and other factors on their respective role and influence of thecorresponding algorithm in convergence rate, steady-state offset, the tracking capability oftime-varying signal and other key performance. Compared the pros and cons of eachalgorithm in these indicators and defined their specific use of the environment. Finally, thesimulated signal was generated after analyzing the characteristics of the target signal. Boththe NLMS algorithm which has faster convergence speed and less steady-state offset,andthe classic Winner filter algorithm were selected to conduct a cancellation simulation ontime domain. The results showed that the NLMS algorithm can eliminate part of the directwave which was contained in the mixed signal, but the multi-signal which has weakenergy was still difficult to separate. The classic Winner filtering algorithm can achievegood effect on the experiment, maybe a viable method of multi-path signal separation. |
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