Time-Frequency Feature Extraction Method for Low Data Rate Micro-Motion Targets of Phased Array Radar

In scenarios of multi-target detection and tracking, phased array radar data rates are often low, and high-speed translation and micro-motions lead to severe Doppler ambiguities, making it impossible for traditional methods to extract time-frequency features. Regarding this issue, this paper first compresses the Doppler range of micro-motion targets based on intra-pulse interference ambiguity resolution. However, the minimum Doppler compression factor of this ambiguity resolution method is the ratio of the radar signal carrier frequency to the bandwidth. In the case of narrowband signals, this compression factor is sufficient to compress the Doppler frequency near zero, making it difficult to obtain time-frequency characteristics; furthermore, a parametric time-frequency analysis method is used to obtain the fine time-frequency characteristics of micro-motion targets. Finally, a micro-motion period estimation was conducted, comparing the root mean square error of period estimation between the method proposed in this paper and the classical Average Magnitude Difference Function (AMDF) method. Simulation results show that compared with traditional methods, the root mean square error of period estimation using the method in this paper is reduced by 13.5 dB.