| The current electromagnetic signals environment has become increasingly complex,electromagnetic signal density has reached millions of magnitude,which requires the recognition of radar signal processing system must have the ability of quick and accurate identification of the threats and bring accurate and reliable information for actual combat.With some new radar signal processing algorithms are put forward,the complexity of the new radar signal processing are also increasing.The higher requirements are put forward for The number of channels and dynamic range of the signal.Multi-channel high speed signal acquisition processing has become the development direction of radar digital receiver.The traditional signal acquisition and transmission method has been unable to fully satisfy the signal processor to process the data under current complex electromagnetic threat environment.Precise and high speed acquisition system,must be applied to guarantee the initiative in EW environment.The research has great and far-reaching significance for a high speed multi-channel digital intermediate frequency receiver with wide band radar signals which can distinguish and identify of radar and decoy,with high sensitivity,high resolution,and can improve the ability of anti radiation weapons to detect,identify,high precision information processing.In this paper,the research of high-speed multi-channel digital intermediate frequency receiver is mainly divided into three aspects.First of all,new method of radar decoy recognition is proposed based on radar signal fingerprint characteristic recognition and polarization mode recognition.Fingerprint identification is mainly combined with digital beamforming for spatial filtering the received signal.And then using the parameters of the part of the collected pulse envelope rise edge as the fingerprint identification of a signal.To complete the recognition of emitter fingerprint features by correlation calculation with template signa of the radiation source.The recognition of radar signal polarization modes is completed with concluded the different characteristics of each polarization mode signal by analyzing the different methods of polarization radar signal representation form.To comprehensive judgement by calculating the difference between the different polarizationmodes of radar signal characteristics.This design completed data collection and test in different polarization modes through joint debugging with microwave front-end.Then,the article introduces the seven channels of digital intermediate frequency receiver hardware circuit design.FPGA has a powerful data parallel processing ability,can satisfy the high speed data processing requirement of the ADC,and it is very suitable for the control core of this system.The high-speed computing power of the high performance multi-core DSP is suitable to be chosen as the complex algorithm of the main processing chip.This article finally complete the platform of high speed seven channel digital receiver board design from introduce the choose of main chip such as the clock,ADC,FPGA and DSP and the peripheral circuit design in detail.Finally,the article complete the sequence configuration and the function of the main chip on the seven channel digital receiver through the FPGA program.The article completion space resolution and identification of the radar and decoy through the function of fingerprint matching and polarization identification.The article verify the performance of this system through the Quartus II and Modelsim,Matlab joint debugging simulation. |
