Design And Realization Of Passive Detection System Hardware Platform Based On Array

With the rapid development of various technologies in electronic warfare,the active detection system has been constrained more and more.Passive detection system for target detection,tracking and location by passive receiving and processing third-party radiation signals has the characteristics of anti-stealth,anti-jamming,anti-penetration at ultra-low altitude and anti-radiation weapons,and has attracted more and more attention from countries.With the development of mobile communication,the passive detection system based on mobile communication signals has a good detection ability for low altitude moving targets,which has a good application value.In this paper,the passive detection system based on array is studied,and the hardware platform of the passive detection system based on array is designed and implemented.Firstly,the basic principle of passive detection system based on external radiator is briefly introduced.Then,the feasibility of using GSM base station signal as illumination source is simulated and analyzed.The results show that the GSM base station signal has a blurred function of thumbtack type and is suitable for passive detection system as external radiation source.The direct wave interference is studied and analyzed,and an adaptive direct wave cancellation algorithm based on NLMS criterion is proposed.The validity of the adaptive direct wave cancellation algorithm based on NLMS criterion is verified by the cancellation results of measured echo signals.Several common array signals are modeled,the principle of adaptive beamforming and its optimal criterion are studied,and the antenna array pattern is analyzed.Then the influence of array structure,spacing and number on signal reception is studied,and the selection of antenna array is completed.According to the overall requirements of the system and the signal processing flow of passive detection system,the overall scheme of the hardware platform of passive detection system is designed.The high performance,zero-IF structure of the RF transceiver chip AD9361 is used as the main chip of the RF front-end,the preamplifier of low noise amplifier is used to realize the four-channel signal reception and processing,and the signal processing platform is implemented with the framework of FPGA+DSP.In this paper,the circuit realization of each module of the hardware platform of passive detection system is introduced in detail.Finally,indoor and outdoor tests are carried out on the basis of the realization of the hardware platform of passive detection system.The test results show that each module works normally,the receiver performance index can meet the system requirements,and the GSM signal reflected by the target can be received correctly.The correctness of the hardware platform of passive detection system is verified.