Design of a Low-Cost Synthetic Aperture Radar for Continuous Ship Monitoring

Abstract

Synthetic aperture radar (SAR) systems have unique image capabilities that are suitable for several Earth observation applications. The focus of this paper is the design of a lowcost SAR for a single dedicated application, namely illegal vessel detection, that can be implemented using a small satellite and is characterized by reduced transmit power and high resolution. Minimum requirements in terms of noiseequivalent sigma zero (NESZ) and resolution that ensure acceptable detection performance are derived, using TerraSAR-X data to retrieve the intensity distribution of typical ships. One peculiarity of the design is that a pulse repetition frequency (PRF) much smaller than the nominal Doppler bandwidth is selected to ensure a wider swath and that azimuth ambiguities are exploited to further improve the detection performance. A design example of a system in Xband imaging a 50-km ground swath and characterized by an average transmit power of only 15 W is presented