SAR Imaging Solutions Based on Azimuth Phase Coding

In this paper the possibility is investigated to reduce the minimum SAR antenna size using azimuth phase encoding. In particular, by applying phase encoding to the transmitted sequence of pulses, the ambiguous returns can be rejected reflected from the adjacent swaths in range. This allows the SAR antenna beam to illuminate an enlarged cross-track area, thus relaxing the constraint on the SAR antenna height at the expense of a smaller maximum achievable range swath size. The new constraint on the minimum antenna height is derived, as well as a possible scheme for integrating the range ambiguity suppression scheme inside the focusing algorithm. Several imaging modes exploiting the azimuth phase coding have been defined both for a single channel and for a multichannel SAR system.