一种提高脉冲雷达多普勒相位精度的方法

针对低信噪比条件下脉冲雷达模糊多普勒相位精度较低,可能导致相位测距时不能正确解相位模糊问题,基于EMD（Empirical Mode Decomposition,经验模式分解）区间阈值去噪方法,提出了一种新的提高多普勒相位精度的方法：利用EMD分解后各层信号的频率特性和能量特性,选取合适的阈值,并对各层信号进行区间阈值化处理,在提高信号信噪比的同时保持了信号的连续性.分别在回波信号噪声为高斯白噪声和AR（2）相关噪声的情况下,以及不同信噪比条件下,对该方法进行验证.仿真结果表明：在低信噪比条件下,当回波信号噪声为白噪声和相关噪声时,EMD区间阈值去噪方法能将回波信号信噪比提高5 dB,去噪性能优于小波阈值去噪方法,其对应多普勒相位精度能提高1倍以上.

A Method to Increase the Doppler Phase Accuracy of Pulse Radars

The ambiguous Doppler phase accuracy of pulse radars is low when SNR （Signal-to-Noise Ratio） is low and this may lead to incorrect resolving of the ambiguity of delta-phase. Using EMD （Empirical Mode Decomposi- tion）-based interval threshold denoising technology, a new method to increase ambiguous Doppler phase accuracy is proposed. Interval threshold is chosen based on the properties of energy and frequency of each IMF （Intrinsic Mode Function）. After interval thresholding on each IMF, SNR is increased and the consistency of the signal is maintained at the same time. The EMI）-based interval threshold denoising method is verified when the noise of received signal is Gaussian white noise and AR（2） correlated noise. Simulation results show that the SNR of the noisy signal can be increased by 5 dB, and the denoising performance is better than wavelet threshold denoising. As a result, the accu- racy of the ambiguous Doppler phase is more than doubled.