Abstract: A method of operating a synthetic aperture radar “SAR” to acquire SAR echo data for the formation of an image, comprises calculating a nadir ambiguity index for the nadir of the platform; determining a frequency sweep direction sequence for successive pulses of a waveform to be transmitted by the SAR based on the nadir ambiguity index; obtaining a relative phase sequence for the successive pulses of the waveform; and encoding the waveform with the determined frequency sweep direction sequence and the relative phase sequence.

Abstract: A satellite (140) for operation in orbit around the earth comprises an ADCS (131, FIG. 1) configured for mechanically steering the satellite in the azimuth direction to prolong a dwell time (1105), during which a selected target is visible from the satellite, as the satellite orbits over the target. A processor at the ground station may be configured to process raw SAR data from any of the satellites described here. The raw SAR data may be processed in a number of ways to provide image information including but not limited to forming multilook images, compiling video sequences and colour coding images.