An Autofocus Algorithm Based on Doppler-domain Multichannel for Airborne SAR
Li Yin-wei① Chen Li-fu② Wei Li-deng① Peng Qing③ Xiang Mao-sheng①
①(Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China) ②(School of Electrical & Information Engineering, Changsha University of Science and Technology, Changsha 410004, China) ③(Shanghai Radio Equipment Research Institute, Shanghai 200090, China)
Abstract：On the basis of the MultiChannel Autofocus (MCA) algorithm and the Fourier-domain MultiChannel Autofocus (FMCA) algorithm, an autofocus algorithm for airborne SAR based on Doppler-domain multichannel is proposed. The proposed autofocus algorithm is also directly derived under a linear algebraic framework, allowing the phase error to be estimated and removed in a noniterative fashion to achieve the well-focused SAR image. However, unlike MCA or FMCA applied to the image domain, the proposed autofocus algorithm is used to estimate the phase error in the range compressed azimuth Doppler domain (azimuth uncompressed). In addition, it does not require the assumption of a low-return region contained to the SAR image, which makes it applicable to the strip-map mode SAR. The processing results of strip-map SAR data in different cases demonstrate the validity and feasibility of the proposed autofocus algorithm.
2015, Vol. 37 
