A Micro-Motion Feature Extraction Method for Rotor Targets Based on Multidomain Parameter Estimation and Phase Compensation

The micro-motion demonstrates a detailed description of the target’s motion, modulating its radar signal in terms of echo, phase, and imaging. In this article, we propose a micro-motion feature extraction method based on multidomain parameter estimation and phase compensation. This method analyzes the periodic peak characteristics of rotor targets in both time and frequency domains. Then, by designing a sliding window peak search algorithm, multiple peaks are extracted, and these are used to estimate the time-domain peak frequency and frequency-domain spectral interval. By comparing the peak frequency in the time domain and the spectral interval in the frequency domain, the odd and even numbers of the rotor target blades are determined, and the rough parameter estimation of the blade number and rotational speed of rotor targets is obtained. Using the estimated parameters to construct compensation factors for phase compensation of the signal, the rotor target blade number is determined through the compensated signal, achieving a more accurate estimation of the blade number and rotational speed and further improving the feature extraction accuracy. The simulation results demonstrate that the method is capable of swiftly and efficiently extracting the features of propeller aircraft and helicopters and has good performance in the case of low signal-to-noise ratio (SNR) or clutter. The effectiveness of the method has also been verified through measurement data.