Preliminary Concepts and Analysis of Future Earth Observation Missions based on Distributed Radars

Spaceborne synthetic aperture radars can gain great advantage from the concepts of formations and distributed space systems. In fact, combination of signals from multiple coherent receivers allows to overcome intrinsic performance limitations of monolithic SAR systems. This paper deals with an overview of recent advances and ideas in the field of distributed sparse/filled aperture radar concepts and required signal processing. Then, preliminary system considerations are given and a preliminary conceptual analysis of a distributed P-band SAR is presented. At low frequency distributed SARs offer greater advantages in overcoming the minimum area constraint (order of several tens of meters) and reduce the impact on formation control feasibility (requirement depends on wavelength). A formation of 6 cooperating satellites carrying a 2 m x 2 m antenna operating at an undersampling pulse repetition frequency of 1000 Hz would allow to achieve 1 m azimuth resolution (ionospheric effect not included) over the whole range swaths.