Small Satellite Dispersed Synthetic Aperture Radar

Abstract

An application example is used to compare several SAR satellite configurations. The application is “Wide-Area Ship Detection combined with High Resolution Ship Imaging”. A phased array reference configuration that is based on a single large satellite is described. The limitations of this configuration are discussed, especially in terms of swath width and power, or rather Noise Equivalent Sigma Zero (NESZ). Phase centers of the reference single phased array antenna, which are acquired in a time sequence, are substituted by simultaneously acquired phase centers of a fractionated configuration with one transmit and several small receive satellites. The along track satellite separation can considerably be extended by a dispersed configuration of small satellites. The dispersed configuration is described and the phase center coverage is mathematically proven. An analysis method is proposed that verifies the coverage of all required phase centers, and a phase center repetition factor is defined. Finally, a feasible dispersed system concept for the exemplary application is provided with a geometric resolution of 10 m at 1300 km swath width in the ship detection mode. In the ship imaging mode a resolution of 1 m is achieved.