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 SARand 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. 1.0 INTRODUCTION The proposed SAR-MTI system is designed for use as an all weather, day and night sensor on board of tactical UAV or small aircraft. Since these platforms have limited resources for the payload, the system has to be compact, lightweight and low power. Still, a high resolution and a covered swath width as large as possible are necessary. Beyond that the system should also cover different modes of operation amongst which Stripmap SAR modes, also known as swath SAR modes, Spotlight SAR modes and Moving Target Indication (MTI) modes. The latter should preferably be able to cover a large area frequently, such that moving targets can be detected and tracked. If possible, an MTI mode should be combined with an imaging mode in order to capture moving as well as stationary targets in the scene simultaneously. The SAR system is designed to accomplish just these tasks. For this purpose the system uses an Active Electronically Scanned Array (AESA) front end which can be split into three subarrays allowing for a very sensitive MTI mode. The use of AESA facilitates the possibility to interleave different modes due to the inertia-free beam steering. For example, Stripmap SAR and scanning MTI can be interleaved. nt van Rossum, W.L.; Grooters, R.; van Halsema, D.; Lorga, J.F.M.; Otten, M.P.G.; Vermeulen, B.C.B.; Vlothuizen, W.J. (2005) Developme of a Small Phased Array SAR-MTI System for Tactical UAV. In Advanced Sensor Payloads for UAV (pp. 23-1 – 23-12). Meeting Proceedings RTO-MP-SET-092, Paper 23. Neuilly-sur-Seine, France: RTO. Available from: http://www.rto.nato.int/abstracts.asp. TO-MP-SET-092 23 1 UNCLASSIFIED/UNLIMITED Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 01 MAY 2005 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Development of a Small Phased Array SAR-MTI System for Tactical UAV 5a. CONTRACT NUMBER