Abstract:

When radar reconnaissance and jamming equipment are faced with complex electromagnetic environments and multifunctional phased array radars， especially the low probability of intercept （LPI） radar， traditional five-parameter analysis appears inadequate. For LPI radar signals， the research on intra-pulse modulation recognition and parameter estimation methods has become a hot topic in the field of radar countermeasures. Based on the short-time Fourier transform （STFT） for the optimization of intra-pulse modulation recognition and parameter estimation， the three-spectral-line method was used to reduce frequency measurement errors； the signal amplitude was corrected through window function filtering to improve the amplitude noise resistance performance of the instantaneous autocorrelation method； a 64-point sliding average was calculated to improve the accuracy of time-frequency estimation. The simulation results indicate that under the condition of a signal-to-noise ratio greater than or equal to 12 dB， the signal recognition rate is better than 95%， and the parameter estimation error is better than 5%.

Key words: low probability of intercept（IPI） radar, short-time Fourier transform（STFT）, three-spectral-line correction, time-frequency analysis, intra-pulse modulation recognition, parameter estimation

摘要：

雷达侦察干扰装备在面对复杂电磁环境和多功能相控阵雷达，特别是低截获雷达（LPI）时，传统的五大参数分析显得力不从心。针对低截获雷达信号（LPI），开展脉内调制识别与参数估计方法研究，已成为雷达对抗领域的热门问题。基于短时傅里叶变换（STFT）进行脉内调制识别与参数估计优化，利用三谱线法减小频率测量误差，通过窗函数滤波修正信号幅度，改善瞬时自相关法的幅值抗噪性能，进行64点滑动取平均值，提高时频估计的精度。仿真结果表明，信噪比大于等于12 dB的条件下，信号识别率优于95%，参数估计误差优于5%。

关键词: 低截获雷达, 短时傅里叶变换, 三谱线校正, 时频分析, 脉内调制识别, 参数估计