The detection of ground moving targets with arbitrary linear motion from an airborne multi-channel radar via a long coherent processing interval is considered. A reparameterization of the target's linear motion is developed which allows for maximizing the target signal energy in synthetic aperture radar images, and decouples the array processing from the image formation process. The algorithm genrates estimates of the target's along-track and cross-track velocity components, making a unique determination of the target's motion parameters possible.