A Two-dimensional Range-azimuth Decoupling Method for Forward-looking array SAR imaging and Variant Compensation
Forward-looking array SAR imaging can achieve two-dimensional resolution of the forward-looking blind area,which is of great application value in military fields such as weapon guidance.However,under special geometric models,the high coupling of range-azimuth and the azimuth variation make high-resolution forward-looking imaging extremely challenging.The accurate echo signal model is derived in the range-Doppler domain based on the geometric configuration of forward-looking array SAR imaging.And the RCM correction with two-dimensional decoupling of range-azimuth is realized through the de-chirping and the Keystone method.On this basis,the target Doppler frequency is decomposed in time once and twice by the proposed method,and linear Doppler frequency interpolation is achieved through resampling.Azimuth residual phase errors in each range bin are eliminated to achieve spatial variation compensation.Finally,well-focused forward-looking array SAR images without ambiguity are obtained through azimuth focusing and beamforming.Simulations of point targets and surface targets verify that effective unambiguous for-ward-looking array SAR imaging can be achieved by the proposed method.
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维普
