Study On The High-precision Intra-pulse Analysis And Sorting Of Radar Signals And Its DSP Implementation

Intra-pulse analysis and sorting of radar signal are important parts of the signalprocessing of radar reconnaissance system. Large scale and high-density radar emittersare employed in modern radar electronic countermeasure (ECM) environment and alsothe simultaneous arriving signals exists. The complex modulated signal with variableparameter which are adopted to meet the requirement of ant-reconnaissance and anti-interference. The intra-pulse analysis and sorting of radar signal became difficult andfacing great challenges. The radar reconnaissance receiver should have the capability ofprocessing simultaneous arriving signals and also the real-time processing.To implement the intra-pulse analysis and sorting algorithm for simultaneoussignals in real time, main work of this dissertation is as follows.1. Phase characteristics of the common radar intra-pulse modulation signals areanalyzed. Algorithm to extract instantaneous frequency based on phase difference isresearched and affect of noise to algorithm is analyzed. Method for computing multiplephase difference is given. Characteristic of instantaneous frequency of the commonradar intra-pulse modulation signals is analyzed.2. An intra-pulse analysis algorithm which uses instantaneous frequency to extractthe characteristic parameters of signal is researched. Using least square method andadaptive histogram statistics to extract characteristic parameters of signal, modulationrecognition for eight intra-pulse modulation radar signal is realized. Based on Fouriercoefficients interpolation and instantaneous frequency measurement, parametersestimation method for eight intra-pulse modulation radar signal is given. Simulationproves the effectiveness of the intra-pulse analysis algorithm.3. A radar signal sorting algorithm based on DDC (Dynamic Distance Clustering)and PRI (Pulse Repetition Interval) analysis is researched. The applicability of differentsorting parameters in sorting algorithm is analyzed. Pre-sorting algorithm for radarsignal based on DDC to dilute dense radar pulse stream is researched. Radar signalsorting algorithm based on SDIF (Sequential Difference Histogram) and the pulse trainsanalysis algorithm to carry on PRI analysis is researched. The estimation of radar signal inter-pulse parameters and analysis for PRF (Pulse Repetition Frequency)modulation-type is realized. Simulation proves the effectiveness of signal sortingalgorithm.4. The function module of digital reconnaissance system is analyzed. Based ondigital reconnaissance system, the hardware structure and platform for signal intra-pulseanalysis and sorting in framework of FPGA+DSPs are given. Hardware implementationmethod for radar signal intra-pulse analysis and sorting algorithm is analyzed. Datatransmission mode between modules and communication mechanism between FPGAand DSP are analyzed. Real-time processing for radar signal intra-pulse analysis andsorting algorithm is accomplished. The effectiveness and real-time performance ofalgorithm are proved by joint debugging of the system.