GeoSTARe initial mission design

GeoSTARe is a proposed geosynchronous synthetic aperture radar (GEO SAR) mission as a hosted payload on a commercial communication satellite. GEO SAR missions have been studied for many years because of their potential for high temporal resolution imaging over continental regions. The large range means that longer signal integration times than for low Earth orbit SAR are required and/or large antennas. The GeoSTARe study includes an analysis of potential user applications for the atmospheric and surface data expected, assuming a mission concept of a broad, L-band, fixed beam plus a steerable X-band beam. A system design methodology is used to propose an outline mission design. This is then used to estimate performance accounting for expected surface backscatter in the different wavebands and the likely incidence angles. Results suggest that GeoSTARe is feasible with an antenna diameter of 6 m and electrical power demand of around 2 kW, and that practically all the identified user requirements can be met. Further work is underway to assess the effects of clutter, typical atmospheric perturbations, and image focussing algorithms.