Discrete Time Signal Processing Of Stepped-Frequencylinear Frequency-Modulated Pulse Radar

One of the major directions for modern guidance radar development is radarimaging with hypersonic missile-borne and long-distance application, of which thekey issues are the precise estimation of target velocity, velocity compensation anddata rate improvement. The paper, based on the systematic analysis of signalprocessing methods of broadband radar imaging mechanism, namely, SF (SteppedFrequency), LFM (Linear Frequency Modulated) and SF-LFM, proposes a method ofvelocity estimation and compensation for SF-LFM pulse radar, which provide afeasible technical means for high-quality imaging and velocity compensation, as wellas a signal processing method of high PRF (pulse-repetition-frequency) SF-LFMpulse radar based on multi-channel processing. The feasibility of target imaging anddetecting in high data rate by this method has been realized through theoreticalanalysis and experimental simulation.In this paper,the mainly research work includes:1. High range resolution imaging algorithm based on SF-LFM pulse radarThe mathematical models of echo sampling signal, IQ quadrature sampling,digital pulse compression and range profile synthesis have been constructed bytheoretical analysis.2. Target velocity estimation and velocity compensation algorithm based onSF-LFM pulse radarA method of velocity estimation based on up-down SF-LFM pulse radar is putforward, which features relatively sound adaptability under extended targets(multi-scattered centers existing in the sampling unit, the width of range resolutionunit is smaller than the target size) and hypersonic conditions, characterized by itssmaller computational work and wider non-vague velocity-detecting range. The paperalso advocates a secondary pulse compression and velocity compensation methodbased on up-down SF-LFM pulse radar, featuring higher velocity compensationprecision and better pulse compression effect.3. Signal processing method based on high PRF up-down SF-LFM pulse radarThe signal model for target echo as well as the mathematical models in the signalprocessing is set up for high PRF up-down SF-LFM pulse radar; a typical parameterdesign and computational simulation are carried out with simulated examples. Theoretical analysis and simulation proves that the feasibility of realizing high datarate and high resolution imaging in hypersonic and long range case by adopting highPRF SF-LFM pulse radar can be achieved.