Target Detection And Positioning Method In Passive Bistatic Radar Based On Beidou Signal

In recent years,as the battlefield environment has become more and more complex,traditional active radars emit high-power electromagnetic waves when they are working,and they are always threatened by the enemy.Therefore,the application of traditional radars has also been limited.More and more researchers have paid more attention to passive bistatic radar that do not emit electromagnetic waves.Based on the unique system of passive bistatic radar,it has the advantages of low cost,relatively small size,low power consumption,difficult to be found and not easily interfered.It can be predicted that the application prospect of passive bistatic radar is quite wide,and it is also the current domestic Hot research in the field of external radar.In this thesis,based on the Beidou satellite as a radiation source target detection and positioning method,the specific work content is as follows:1.Analysis of Beidou satellite signal performance.First,a brief introduction to the development of the Beidou navigation system;then focus on the analysis and discussion of the radiation source Beidou satellite signal,mainly from the C/A code generation principle,signal composition,fuzzy function and target maximum detection distance,etc.Introduced and simulated the signal,the signal ambiguity function and the maximum detection distance of the target.The results show that the Beidou satellite signal bandwidth is moderate,the ambiguity function is "pushpin",has good speed resolution and distance resolution,theoretically Achieve close-range target detection.In summary,the Beidou satellite signal is an ideal radiation source.2.Beidou satellite direct wave and target echo signal processing.Firstly,it introduces the work flow of radar target detection of passive bistatic radar,and then focuses on the research of reference signal purification method and clutter cancellation correlation algorithm.When researching reference signal processing,this paper uses signal reconstruction to perform direct wave purification,and measures the performance of the reconstruction method by bit error rate and signal distortion;when studying echo signal processing,it first introduces Three commonly used time-domain adaptive filtering algorithms filter out direct waves and multipath interference in the echo signal.The performance of the three algorithms is compared through simulation.The results show that these three algorithms can achieve clutter cancellation,but LMS(NLMS)And the RLS algorithm also have an effect on the target echo signal and the processing speed is slow,and the faster processing speed ECA-B algorithm can suppress the clutter while also ensuring that the target echo signal is almost not affected.-B has the best performance.3.Research on target positioning method of Passive bistatic radar based on Beidou satellite.First,the basic principles of the three single-measurement positioning methods are briefly introduced,including AOA,TDOA and FDOA;then the error equation and GDOP of each single-measurement positioning method are derived and calculated,and under the background of using Beidou satellite as the radiation source Simulation and analysis were carried out,and the positioning accuracy of each positioning method was compared through simulation.The advantages and disadvantages of each positioning method were summarized.Finally,in order to make up for the disadvantages of each positioning method,the multi-measurement joint positioning method was considered.The error equation and GDOP of the multi-measurement joint positioning method are solved,and simulation and analysis are carried out.It can be seen from the comparison and summary that the positioning accuracy based on the TDOA and FDOA joint positioning method is generally higher than other positioning methods.However,when this method is actually used,it is necessary to appropriately adjust the position of the receiving station to obtain a better positioning effect.