Research And Implementation Of LPI Radar Reconnaissance Technology Based On Channelization

In the modern information war,battlefield information is complex and changeable,the signal density of communication and radar is very high,the signal intra-pulse modulation and its frequency are varied,and various types of interference overlap with each other,all of these put forward higher requirements for electronic warfare reconnaissance receiver,while the channelized receiver has advantages of wide band coverage,large dynamic range and high sensitivity,is widely used in modern electronic warfare receivers.This paper focuses on the research and implementation of channelized receiver based on polyphase filter,on the basis of this,analyzes and studies the multi-phase FFT channelization structure,gives the theoretical simulation and hardware implementation results.First of all,for signal detection problems after channelization,an adaptive threshold setting method which using the combination of auto-correlation cumulation and median filtering algorithm is given,which effectively solves the detection problem of different signals with different power levels arrive at the same time in low SNR.Secondly,make use of the different time-frequency parameters of different intra-pulse modulation signals,analyzes the recognition method of signal intra-pulse modulation type,and give the flow chart of signal identification,at the same time,the recognition method of phase modulation signal with high code rate is analyzed by using the correlation characteristic of cyclic spectrum,and the new recognition strategy and result are given.Finally,a polyphase filter digital channelized receiver and the signal processing module is implemented based on FPGA hardware platform,gives the simulation results of some key structures,and the hardware platform is tested for its function and performance.In addition,the multiphase FFT channelization structure is implemented and verificated with software simulation.In this paper,the efficient channelization structure of polyphase filter was validated from the aspects of theoretical analysis,software simulation and hardware implementation,gives the complete signal detection,channel decision and signal intra-pulse modulation type identification process,tested and analyzed the polyphase filter channelization on hardware.The multi-phase FFT channel structure has been analyzed and verified through simulation,and the future research directions in channelization are also given.