Synthetic aperture radar （SAR） is an important tool in microwave remote sensing. Among SAR techniques

SAR processing

which processes the received signal into SAR images

is the key point In fact. synthetic aperture is realized by SAR processing. Different algorithms for SAR processing are described and a matched filtering with Chirp Scaling algorithm is presented. It removes the interpolation step for range cell migration correction （RCMC） and accomplishes better phase preserving and focusing. The images processed are superior to those obtained by other SAR algorithms.