Feasibility of spaceborne bistatic radar missions for land applications

This paper deals with a feasibility analysis of spaceborne bistatic missions for Earth Observation, with signals at microwave bands. The analysis, performed in the frame of a wider study financed by ESA, considers as input bistatic configurations, investigated in another paper, suitable for typical land applications i.e. soil moisture and vegetation biomass retrieval. Signal sources are GPS constellation and spaceborne SAR´s. This analysis mainly encompasses the design of possible orbits implementing the desired bistatic configurations, and the characterization of the system performances. The latter are evaluated through several different parameters, grouped in two classes: target observation parameters, strictly related to the illuminator-target-receiver geometry at given epoch (e.g. signal to noise ratio, spatial resolution, observation angles) and system parameters such as: spatial coverage (measuring whether or not a point is accessible by the satellites in bistatic configuration), number of bistatic accesses to the target area, revisit time (indicating the delay between two successive bistatic acquisitions of the same area).