This paper addresses the ground moving target indication (GMTI) performance of space-based multi-channel synthetic aperture radar (MSAR) systems as they suffer from the high speed of the radar platform leading to a wide spread clutter spectrum and compares it with the air-based case. Opposite to classical GMTI systems near future space-based SAR systems offer only few simultaneous channels and relatively low pulse repetition fre-quency (PRF). The influences of PRF, antenna size and number of channels on detection performance are stud-ied. The analysis is based on a post-Doppler approach of the optimal processor since this has the advantage that in case of stationary clutter the clutter contributions can be assumed statistically independent for each Doppler cell
