Software Defined LFM CW SAR Receiver for Microsatellites

Abstract

There is an increasing demand for a low cost, day-night, all weather spaceborne imaging capability using synthetic aperture radar (SAR) on small satellites. Traditional pulsed SAR payloads have been too expensive and too power demanding to be employed on low-cost microsatellite platforms. Recent developments based on Continuous Wave (CW) techniques have proved successful in minimizing the cost, mass and power of SARs for small airborne platforms (UAVs). However, when considering the use of CW techniques for space based SARs, other considerations come into place: A major one being need of high isolation between transmit and receive antennas, in short, a bi-static configuration. Conventional receiver designs based on analogue demodulation techniques remain inflexible and are complicated to change to suit changing operational requirements in a dynamic bi-static satellite formation. This chapter focuses on the research being carried out in the Surrey Space Centre (SSC) on the design and development of a software defined linear frequency modulated (LFM) CW SAR receiver that can be used on bi-/multi-static microsatellites for remote sensing.