[O07] Signal Processing Techniques to Reduce the Clutter Competition in Forward Looking Radar
Radar systems placed in the nose of fast moving jets have to detect moving targets, the radial velocity of which is close to that of the surrounding clutter, relative to the platform's speed. A widely used moving target detection strategy for moving platforms is that of space-time adaptive processing (STAP). STAP is now readily applied to the case of a sideways-looking array, where the majority of the clutter occurs along a narrow ridge, which crosses the angle-Doppler graph diagonally. When the array orientation is at an angle (termed the crab angle) to the direction of platform motion, the clutter at a given range no longer occupies the diagonal ridge, but an ellipse. The eccentricity of the ellipse decreases as the crab angle increases, so that when the array is forward-facing with respect to the platform motion, clutter forms a circle on the angle-Doppler plot. It is far more difficult for the STAP to compensate for this clutter because it is now range dependant. As such, ground clutter is range ambiguou, and the clutter arcs at different ranges and angles can interfere with the detection and tracking of targets. Thus the performance of the radar is reduced because of the increased clutter power competing with the target's signal. Current research has concentrated on altering the STAP architecture to cope with the range dependent returns. However, there is already a mechanism which can help mitigate the Doppler-range ambiguities, but which is not used in the adaptive part of the STAP architecture. This, of course, is the matched filter and its ambiguity function. This research will develop methods to efficiently and adaptively design the transmitted waveform based on the received signals. The study will encompass the use of the received signals, prior knowledge of target and clutter locations, and spatial beam pattern of the array on transmit and receive, in designing the signal.
Project Supervisor
Dr. Mathini Sellathurai is currently a Reader in Digital Communications and Signal Processing with the Institute of Electronics, Communications, and Information Technology, School of Electronics, Electrical Engineering, and Computer Science, Queen’s University Belfast, Belfast, U.K. Her current research interests include adaptive and statistical signal processing, space-time and MIMO communications theory, information theory and cognitive radio with applications in radar technology, telemedicine, underwater communications, satellite communications, and future wireless networks. Her current research has been funded by EPSRC under EP/D07827X/1 for advanced signal processing techniques for multi-user multiple-input multiple-output broadband wireless communications; MIMO-RADAR and waveform agility to improve low elevation target detection (also partially supported by QinetiQ, Portsmouth); EP/G026092/1 for Bridging the gap between design and implementation of soft-detectors for Turbo-MIMO wireless systems and EP/H012257/1 for Signal Processing Techniques to Reduce the Clutter Competition in Forward Looking Radar. She is also receiving European Union Frame Work 7 Funding for Cognitive radio oriented wireless networks. Dr. Sellathurai was the recipient of the Natural Sciences and Engineering Research Council of Canada’s doctoral award for her Ph.D. dissertation and a co-recipient of the IEEE Communication Society 2005 Fred W. Ellersick Best Paper Award. Dr. Sellathurai is currently serving as an Associate Editor for the IEEE TRANSACTIONS ON SIGNAL PROCESSING and also an organizer for the IEEE International Workshop on Cognitive Wireless Systems, IIT Delhi, India, 2009. She has been a Technical Program Committee member for the IEEE International Conference of Communications from 2004 to 2010.
