两种基于分数阶模糊函数的运动目标检测方法

针对海杂波中运动目标较微弱的特点,推导了单频信号、LFM信号以及相位含有三次项回波信号的分数阶模糊函数的时移特性及正负对称旋转角的分数阶模糊函数,得到2个有用的结论:(1)延时单频信号和延时LFM信号的分数阶模糊函数模函数与时域延时无关,而对于相位含有三次项的回波信号,其延时信号与原信号的分数阶模糊函数模值相等,但其最大值位置不同,与延时有关;(2)单频信号和LFM信号的正负对称旋转角的分数阶模糊函数模处处相等,而对于相位含有三次项的回波信号,其模幅度差别很大。根据此特性提出了2种基于分数阶模糊函数的运动目标检测方法。IPIX实测数据验证表明了文中方法的有效性。

Two Methods of Moving Target Detection Based on Tractional Ambiguity Function

In the paper, the time shift characteristic and the FRAF modules with two symmetry inverse rotation angles of the monochromatic signal, LFM signal and signal which phase has thrice-order term is studied. Two conclusions are obtained: one is that the FRAF module of time-delay monochromatic signal and time-delay LFM signal has no relationship with time delay. However the FRAF module of the signal which phase has thrice-order term is equal to the FRAF module of the time-delay signal, but has different maximum position which has relation with time-delay. The other is that the FRAF modules with two symmetry inverse rotation angles of monochromatic signal and LFM signal are same to each other. The FRAF module of the signal which phase has thrice-order term has big difference with its FRAF module with symmetry angle. Based on these characteristics, two new methods for detecting the signal which phase has thrice-order term are proposed. Experiment using the IPIX data shows the validity of the methods of the paper.