Research And Implementation Of Low Probability Of Interception Radar Signal Receiver

In recent years,the electromagnetic environment has become more and more complex.In order to improve the survivability of radar on the battlefield,as far as possible to reduce the probability of radar intercepted by the enemy,low probability of intercept radar signal is more and more widely used in a variety of radar systems.It is imminent to study a digital reconnaissance receiver for low intercept probability radar signals.Due to its low probability of interception,the monitoring bandwidth of the digital reconnaissance receiver must be large,the dynamic range must be wide and must have the ability to detect a variety of low intercept probability signals.Based on the channelized receiving structure,the research on the digital reconnaissance receiver of low probability of intercept radar is studied.The main contents are as follows:1.High-speed data acquisition for low-intercept probability signals is discussed in this thesis.A multi-phase filtering based on bandpass sampling is realized in this thesis.In this thesis,the time domain detection,frequency domain detection and differential filter signal detection are studied,and the simulation results of the detection algorithm are given.A real channel decision method based on instantaneous frequency is discussed.2.In this thesis,we discuss the problem of multi-signal separation overlapping in time domain but not in frequency domain,and give a separation algorithm to complete the separation of multi-signal3.The instantaneous frequency characteristics of the LFM signal,two-phase coded signal,four-phase coded signal,non-linear frequency modulation signal,two-frequency coded signal and LFM-BPSK composite modulated signal are analyzed.A method based on the phase difference is obtained.The algorithm is used to extract the instantaneous frequency characteristic parameters of the signal by using the least squares method and the histogram statistic.At the same time,the parameters estimation algorithm of Fourier coefficient interpolation iteration,linear frequency modulation and instantaneous frequency measurement is studied,and the modulation type recognition of common LPI radar signal is completed,And the pulse estimation algorithm is simulated.4.Introduces the system architecture and working mode based on FPGA digital reconnaissance receiver.The whole system consists of ADC,FPGA,PC software.This thesis studies the implementation of high-speed data acquisition with low intercept probability signal.The hardware implementation of channelization and channel detection is completed,and the implementation result is given.The realization process of pulse signal modulation type recognition algorithm and parameter estimation algorithm is completed and the system test is carried out.The concrete results of recognition probability and parameter estimation are given.