Removal of Synthetic Aperture Radar Range Ambiguity by Observing Adjacent Regions

Suppression of range ambiguity is one of the most important issues in synthetic aperture radar (SAR) observations. Range ambiguity is a phenomenon caused by scattered signals from outside of the desired observation range illuminated by preceding and/or following pulses, resulting in a blurred signal in the focused SAR image. Existing solutions such as waveform diversity-based methods and digital-beamforming (DBF) systems increase the complexity of SAR in both hardware and software domains. On the other hand, the recent emergence of commercial SAR services, which apply a constellation of small satellites, demands a simpler solution. To meet this demand, we propose to solve the problem by using the similarity between the range ambiguous signal and the observation swath signal of another acquisition. That is, we consider the case in which two satellites observe the adjacent swaths independently so that an ambiguous swath for one satellite becomes the observation swath of the other one. Experimental results showed that the proposed approach makes it easy to detect and suppress strong range ambiguities.