GEO SAR interferometry: Theory and feasibility study

Geosynchronous Synthetic Aperture Radar (GEO SAR) is the satellite running on the 36,500-Km altitude orbit, and its period is almost 1-day. As we all know, if there is no effect of perturbation force, the orbit of the GEO SAR will coincident exactly per period, and there will be no baseline to achieve interferometry. However in practice, there are varieties of perturbation force in the space, so the orbit in different periods is no longer coincident, which makes it possible to achieve interferometry. In this paper, we study two typical GEO SAR orbits, and analyze the nadir-point trajectory excursion due to orbital perturbation using the software STK (Satellite Tool Kits, AGI). Based on the interferometry theory, we define the repeat-pass baseline of the GEO SAR, and obtain the height measurement accuracy of different kinds of orbits. At last, we verify the feasibility of GEO SAR interferometry by simulation.