Recently

SAR (Synthetic Aperture Radar) is evolving to become an indispensable tool for earth observation and military reconnaissance. The collection capacity for SAR images is growing rapidly， and along with that growth is the expanding need for automated or semi-automated exploitation of SAR images accurately and efficiently. Automatic target recognition (ATR) is an important aspect of automatic or semi-automatic SAR imagery interpretation. An ATR algorithm finds target like regions (regions-of-interest (ROIs)) within a SAR image and computes a class for each ROI. The meaning of SAR ATR is explained

and the general architecture of SAR ATR system is introduced in this paper. SAR ATR systems are analyzed and classified according to their classification methods. The main difficulty of SAR ATR is analyzed

the present state and the future direction of SAR ATR research are also introduced.