Performance Evaluation Of DTMB Passive Radar Reference Signal Error Correction Algorithm

Passive radar is a new system radar that uses non-cooperative sources as detection signals.Compared with traditional active radar,it has green environmental protection,is easy to deploy,and is good at low-altitude detection and other technical advantages.In 2006,China launched a digital TV standard with independent intellectual property rights,DTMB.So far,the signal transmission tower has covered34 provinces,municipalities(including Hong Kong,Macao and Taiwan)in China,which has created good conditions for Chinese researchers to conduct research on DTMB-based passive radar.Because the specific content of the transmitted signal cannot be predicted,the passive radar has very high technical requirements for obtaining a pure transmitted signal.Passive radar based on digital signals uses a reconstruction algorithm based on "demodulation-recoding" to purify the received "direct wave".Channel error correction is one of the key links of the reconstruction algorithm.Noise is inevitably introduced during the signal transmission at the transceiver end,resulting in an increase in the data error rate,which may have a serious impact on radar detection performance.Therefore,this paper mainly conducts an in-depth study on the impact of bit error rate(BER)and channel error correction technology in reference signal reconstruction on radar detection performance.The main work and innovations of this article include:1.The error correction algorithms of LDPC codes are studied,including hard-decision BF algorithm,mixed-decision WBF algorithm,and soft-decision NMS algorithm,and the error correction performance,computational complexity,and serial calculation time-consuming of the three algorithms are thoroughly compared;In order to solve the problem that the error correction algorithm cannot run in real time in CPU serial computing,this paper presents three kinds of error correction algorithms based on GPU parallel computing,and analyzes the resource consumption and time-consuming situation of parallel computing.2.The effects of BER and channel error correction techniques in reference signal reconstruction on radar detection performance are studied.Firstly,under different constellation modes and different LDPC code rates,the difference in the impact of BER on radar detection performance is analyzed.Then the impact of different error correction algorithms on radar detection performance is analyzed.Through simulation analysis and measured data verification,when the signal-to-noise ratio(SNR)is appropriate,the error correction algorithm has a significant effect on the performance of the radar;when the SNR is too low,because the data BER exceeds the algorithm's error correction capability,it will not bring any improvement effect.For the BF algorithm and WBF algorithm,it will even cause greater deterioration in radar detection performance;when the SNR is too high the radar detection performance has reached the best.At this time,the performance cannot be improved by channel error correction.