Development of a Small Phased Array SAR-MTI System for Tactical UAV

A small SAR-MTI system is being developed at TNO, aimed at deployment on tactical UAV, such as the SPERWER, in use with the Royal Netherlands Army. The system makes use of modern front-end technology, to provide flexible SAR imaging and MTI modes. Major design goals are 40 kg weight, 500 W power consumption and 50 cm resolution in order to comply with typical tactical UAV constraints and applications. The use of an active phased array antenna has several distinct advantages, not yet found in existing SAR-MTI systems of this small size. The active electronically steered array (AESA) antenna allows the system to be fixed-mounted on the platform, eliminating the need for gimbals, and enables simultaneous SAR- and scanning MTI modes. The prototype will have a single receive channel, while provisions for extension to 3 parallel receive channels are made, enabling the antenna to be divided into sub-apertures: this will allow advanced MTI processing techniques (STAP) to be applied, increasing MTI sensitivity, target localisation accuracy and lowering of minimum detectable velocity (MDV). A podded version will be demonstrated in flight on a motorglider platform. Apart from the front end, maximum use is made of COTS components for system development. This paper describes the system concept and main components, projected operational capabilities and processing aspects.