Research On Signal Level Fusion With Cooperative Multi-Static Radars

Recently years,with the high speed improvement of the technology,all kinds of new weapons and defense systems have been developed fast,which plays as an important role in the national defense.In order to seize the initiative in military operation,radar are used to accomplish the battlefield observation and situation assessment.But the detection probability of single radar is greatly reduced because of many reasons such as serious clutter interference,stealth aircraft and small SCR targets.So the cooperative multi-static radars become a development trend.Thus the system detection capability can be highly improved by using information fusion technology.The multi-static radars system with multi-band cooperative mode is researched in this study,which is used to detect the small target on the sea-surface by using signal level fusion.The main work done in this study is as follows:(1)The time-space synchronization of multi-radar signal process simulation system is built and the spatial-temporal correlation of sea clutter is analyzed.The K-distribution of sea clutter is simulated.The prepare work such as choices of transmitted wave-forms,simulation of echo signal,transformations of coordinate system are done.What's more,the signal pre-processing work such as quadrature demodulation and pulse compression are done,which are the foundation of the signal level fusion.(2)The basic theory of cross correlation fusion algorithm is analyzed according to the correlation of the random signal.The signal level cross correlation fusion system of the three radars received signal is established and simulated under the built multi-static radars system.It is obviously that the SCR of the fused signal is much higher than that of the single radar system by analyzing statistics of simulation.(3)Time-delay estimation by using higher order cumulant is done and the result is used to compensate the delay-time when fusing the signals by cross correlation algorithm.It makes the target signals fuse under the best situation.It is proved that cross correlation fusion with the time-delay compensation can get better result than the fusion without it.(4)The influence to the feature of clutter by fusion is analyzed.The application scenes of some normal kinds of CFAR(constant false alarm rate)detectors are compared,as well as their pros and cons.The censored order statistic small selection CFAR algorithm is proposed according to the feature of fused signal.The multi-targets jamming detection probabilities of these CFAR algorithms under the same SCR are analyzed by simulation results.The censored order statistic small selection CFAR is better while dealing with multi-target jamming.