LPI Radar Detection Based On The Theory Of Blind Source Separation

With the rapid developments of radar countermeasure technology and anti-radiation missile(ARM)technology,a radar's ability of anti-detection has become the decisive component of the accomplishment of the combat mission.This ability also makes the radar keep surviving on the battlefield.For these reasons,Radars have adopted techniques such as power management,pulse compression,ultra-low side-push valve and so on to reduce the probability of being intercepted by the enemy.This technology is called LPI(Low Probability of Interception)technology.With the continuous application of LPI technology,the battlefield electromagnetic environment is becoming more and more complex.The traditional signal processing theory has become invalid.This question has become the bottleneck of the development of electronic reconnaissance equipment and has seriously harmed the overall combat effectiveness of our army.For this reason,the research of LPI radar signal detection technology is urgently needed.This paper studies the separation and detection of time-frequency aliasing multi-component radar signals under the condition of low SNR the problem.The main research contents are as follows :(1)A signal model suitable for multi-channel interception receiver is established.Based on the independent component analysis(ICA)and the statistical characteristics of the signal,the separation of multi-component time-frequency overlapped signals is effectively solved by using the multi-channel detection model under the framework of blind separation theory the problem is that it can effectively separate the time-frequency overlapped signals.(2)For the problem of multi-component LPI signal interception with time and frequency overlapped,strong and weak,the signal separation is realized by Fast TCA.For reduces the computation of the Fast ICA method,the traditional fast ICA method is improved based on steftenen acceleration method.The real-timeperformance of signal separation is improved.The simulation results show that the improved Fast ICA method based on the steffetsen acceleration method can effectively separate the multi-component LPI signals with different time and frequency and different strength under the condition of low SNR,and the retraction speed is better than the original algorithm.(3)For the application of continuous wave or quasi-continuous wave LPI radar signal detection,a signal detection method based on periodic Fr FT is proposed.This method can accumulate signals with multiple modulation periods at the same time energy,and significantly improves the detection performance of multi-period LPI radar signals.The simulation results show that the detection performance of the periodic Fr FT is better than that of the traditional Fr FT detection method.A radial integration method based on integral rotation factor is proposed to detect LPI radar signal.The time-frequency distribution of signal is first obtained based on CWD time-frequency analysis,then the image is binarized and refined.Finally,the LPI radar signal is detected by radial integration.The simulation results show that the LPI radar signal can be detected at a low SNR.