Optimizing Azimuth Antenna Steering: beyond TOPSAR
Davide, D'Aria; Fabio, Rocca
Politecnico di Milano

The paper discusses some SAR acquisition schemes that exploit flexible antenna steering for burst mode acquisition. The object of such schemes is to provide coverage larger than STRIPMAP SAR, that allows for either for global revisit or small antenna spaceborne missions. It has been shown recently that a viable alternative to ScanSAR can be provided by cyclically sweeping the azimuth antenna beam, leading to TOPSAR (or SweptSAR) mode. TOPSAR’s major advantage is the removal of scalloping; however the wide angular aperture swept introduces some drawbacks, like the lack of interferometric cooperation with other modes, or the presence of grating lobes due to the implementation of the beam steering. In this paper, we investigate such problems and propose different scanning schemes, like the TOPS-SPOT, that provides different trade-offs in terms of scalloping, ambiguities, NESZ and interferometric performances. For each scheme, a suitable processor is discussed. Results in terms of quality performances are shown based both on theoretical analysis and simulations.