Chirp Selection and Data Compression for Spaceborne Wide-Swath SAR in FScan-Mode

FScan has recently been proposed by Airbus DS as an appealing option to implement high-resolution wide-swath (HRWS) spaceborne SAR imaging. The concept uses the fanning-out beam pointing characteristic of phased array antennas operated at high bandwidth in a favorable way to steer the beam over a much wider swath as the nominal beamwidth would correspond. This paper treats the transmit pulse chirp length as a trade-off parameter and consequentially derives two variants of the FScan modes. The consequences on echo window length and the benefits of dedicated onboard processing for data volume reduction are discussed. In this context, the advantages of using a transform domain BAQ are pointed out.