A unified error estimation method for multi-modes SF-SAR in bandwidth synthesis processing

Stepped frequency chirps can be used to generate high resolution range profiles (HRRP) by using spectrum synthesis. There are three distributed modes of stepped frequency SAR (SF-SAR). However, the presence of channel phase errors may degrade the performance of HRRP synthesis. This letter presents a unified error estimation method to address this problem. First, to obtain a focused sub-band image, a range phase adjustment by contrast enhancement (RPACE) algorithm is proposed to estimate inner-channel high-order phase errors. Second, a side-lobe balanced model (SLBM) is established to estimate constant phase error from the relationship between the balanced side-lobe and constant phase; the constant phase error can be directly obtained in an efficient manner. Experimental analysis using real data demonstrates the effectiveness of the proposed method.