Detect and autofocus the moving target by its range walk in time domain

Due to its radial velocity, the range walk (linear term of range migration) of a moving target in synthetic aperture radar (SAR) image is usually bigger than that of the stationary target. Hence in the time domain after range cell migration correction, the trajectory of most moving target is usually characterized by an approximate sloping line, while the trajectory of stationary targets is lines parallel to the azimuth direction (flight path). Exploiting this difference, we propose a novel ground moving target indication method to detect the moving target in time domain, which is different from the conventional methods. The proposed method has the advantage of detecting the slow moving target and can be used in low pulse repetition frequency SAR. Moreover, an autofocus technique is proposed to improve the focusing effect and the parameter estimation accuracy of the moving target. Raw SAR data is used to demonstrate the performance of the proposed method.