Automatic algorithm for estimating the jet engine blade number from the radar target signature of aircraft targets

Radar is a powerful tool for detecting and tracking airborne targets by day and night. Nowadays, noncooperative target recognition (NCTR) is considered an important subject. NCTR means technologies provide high-resolution target signatures and use them to make some decisions about the type of target that has been detected. Clearly, this function is performed with no cooperation from the target concerned, and it may even not be aware that its signature is being measured for recognition purposes [1]. Jet engine modulation (JEM) [2]-[4] generated by the engine rotation in an aircraft has been used for radar-based NCTR purposes, along with high-resolution range profile and inverse synthetic aperture radar (ISAR) [5]-[7]. Recognition by JEM uses micro-Doppler features induced by a rotating jet engine compressor. The micro-Doppler is characterized by a time-dependent Doppler shift that is different from that caused by the target bulk motion.