机载下视阵列合成孔径雷达成像的微多普勒效应
Micro-Doppler effect for airborne downward-looking array SAR imaging
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摘要: 机载阵列合成孔径雷达(SAR)采用机翼共形天线,机翼振动会引起回波相位误差而导致成像散焦。基于微多普勒模型和时频分析方法,研究了机载下视阵列调频连续波(FMCW)SAR成像的微多普勒效应。对振动模型进行了建模,结合阵元振动几何模型分析了信号特点,并基于时频分析方法对下视阵列FMCW SAR的微多普勒效应进行了成像仿真分析。结果表明,该方法可准确估计下视阵列SAR天线振动误差。Abstract: Imaging defocusing may occur due to phase error induced by vibration of conformal antenna array fixed on wings of airborne array synthetic aperture radar(SAR).Micro-Doppler effect of airborne downward-looking array frequency modulated continuous wave(FMCW)SAR imaging is studied based on micro-Doppler model and time-frequency analysis method.Vibration model is established combined with array antenna vibration geometry model, and signal characteristic is analyzed.Then,imaging simulation and analysis of micro-Doppler effect are carried out based on time-frequency analysis method.Results indicate that the proposed method can realize accurate estimation of the antenna array vibration error.