FEATURE EXTRACTION OF MICRO-MOtlON FREQUENCY AND THE MAXIMUM WOBBLE ANGLE IN A SMALL RANGE OF MISSILE WARHEAD BASED ON MICRO-DOPPLER EFFECT

摘要

Micro-Doppler,effect is induced by the micro-motion dynamics of the radar target itself or any structure on the target. In this paper, a simplified cone-shaped model for ballistic missile warhead with micro-nutation is established, followed by the theoretical formula of micro-nutation is derived. It is confirmed that the theoretical results are identical to simulation results by using-short-time Fourier transform. Then we propose a new method for nutation period extraction via signature maximum energy fitting based on empirical mode decomposition and short-time Fourier transform. The maximum wobb|e angle is also extracted by distance approximate approach in a small range of wobble angle, which is combined with the maximum likelihood estimation. By the simulation studies, it-is shown that these two feature extraction methods are both valid even with low signal-to-noise ratio.