A Conceptual Performance Study on a Two-Look ScanSAR Mode Configuration for the Forthcoming ROSE-L Mission

This work shows that additional ScanSAR capabilities, with respect to those achievable through the current synthetic aperture radar (SAR) system of the forthcoming Radar Observation System for Europe at L-band (ROSE-L) mission, may be easily enabled through a proper shaping of the azimuth pattern of the TX radar antenna. In particular, we show that by properly acting only on the distribution of the input excitations of the elements of the currently designed TX antenna array, we can move from a single azimuth-look ScanSAR configuration to a more attractive two-look one. This result is achieved without upsetting the current system architecture and without changing the current mission parameters [such as azimuth resolution, range swath, and pulse repetition frequency (PRF)], all tailored to a one-look ScanSAR configuration. On the other hand, the proposed two-look mode requires to double the azimuth beamwidth with respect to the one-look mode, thus leading to an unavoidable antenna gain decrease, whose amount is approximately 3 dB. The presented analysis also shows that, by still acting on the distribution of the input excitations of the TX antenna array, the scalloping effect can be significantly mitigated with respect to that of the current system design, in both scenarios relevant to the original one-look ScanSAR configuration and the proposed two-look one.