Research About Target Detection In FOD Radar

Foreign Object Debris(FOD) refers to small objects which do not belong to but appear on the runway and might harm airplanes. These objects threaten the safety of travelers and may cause big economic losses. Therefore, it is necessary to develop an advanced automatic FOD monitoring system and study effective detection algorithms.For the purpose of FOD detection, we firstly present the structure of a FOD monitoring system which is based on radar and optical sensors, then propose several effective constant false alarm rate(CFAR) algorithms for radar automatic target detection. The main work and innovations are summarized below.(1) The structure and working pattern of a compound FOD monitoring system based on radar and optical sensors are studied, and the structure and signal processing methods of the radar sub-system are discussed.(2) The classical spatial CFAR detectors are studied and their limits are analyzed.Then two improved CFAR algorithms are proposed by using the detection results of the lagging range cells as prior knowledge. Their detection performances in different environments are analyzed as well. Both theoretical analysis and experimental results demonstrate the priority of the proposed algorithms to the classical CFAR detectors for both single and multiple targets detection in homogeneous clutter environment.(3) By utilizing the distribution information of practical airport runways, a fusion CFAR strategy is presented by combining more than one different CFAR algorithms together. Experimental results show its effectiveness.(4) To improve the performance of the classic clutter-map CFAR algorithm in low SCR(signal-to-clutter ratio) environment, a modified algorithm is proposed based on multi-frame data and two-level detection thresholds. The detection and false alarm probabilities of the proposed clutter-map CFAR algorithm are analyzed and its performance is verified by experimental results.(5) The effectiveness of the proposed methods is further demonstrated based on measured data which is acquired on a real airport runway with the radar experimental system.