Lss-Target Detection And Location Based On Mobile Communication Signal

Compared with traditional active radar,passive radar has better "four countermeasures" performance: anti-radiation missile and bombing,anti-stealth,anti-ultra-low altitude penetration,anti-reconnaissance and electronic interference.With the continuous development of modern wireless communication technology,the communication system is constantly updated,the fourth-generation mobile communication technology has been popularized,and the fifth generation mobile communication technology is also being developed.The research of passive radar system using civil signal as external radiator has been paid much attention."Low-slow and small" target is difficult to be detected by radar because of its small reflection cross-section,low-altitude/ultra-low-altitude flight and slow flight speed.In order to resist the threat and improve the detection and recognition ability of air defense system to low-altitude/ultra-low-altitude target,this thesis uses the mobile communication signal emitted by the communication base station as the external radiation source to detect and locate the "low-slow and small" target.This thesis mainly completes the following contents:1?The fuzzy function is used as a tool to analyze the performance of three mobile communication signals of GSM,WCDMA and LTE applied to passive radar detection.By comparison,it is concluded that the LTE signal has better range resolution and speed resolution,which is very suitable for passive radar detection.2?Aiming at the direct wave cancellation module in the external radiation source radar detection system,a method based on signal demodulation and remodulation is used to perform direct wave purification and cancellation.Compared with the traditional auxiliary antenna method,the direct wave interference can be suppressed more effectively,thereby separating the target echo and the direct wave,which provides a good basis for subsequent signal processing.3?Aiming at the characteristics of LSS-Target detection for time delay and Doppler information extraction,a segmentation method for target echo signals and direct wave signals is proposed.It can be applied to segment matching filter-FFT joint processing and reduce the amount of calculation.Then use CFAR detection technology to achieve "low slow and small" moving target detection.4?Aiming at low-altitude/ultra-low-altitude flight for LSS-Targets,passive time difference positioning system with different heights is studied.Using GDOP distribution to measure the positioning accuracy of multiple station modes and analyze the influencing factors of positioning accuracy.Finally,the research selects the optimal station mode,and adopts the star cloth station to realize the high-precision positioning and flight height measurement of the LSS-Target.