低信噪比下机载平台多脉冲激光测距机目标回波降噪算法

针对远距离飞机目标，机载多脉冲激光测距机通常采用数字化处理体制，影响其测距精度的因素包括发射激光脉冲宽度的距离分辨率、大气传播及目标反射特性造成的波形展宽、回波信号接收处理通道的非线性相频特性等。数字化采样率、回波信号降噪、目标峰值点位置估计等数字化处理过程引起较大的目标距离定位误差。提出了基于经验模态分解（Empirical Mode Decomposition，EMD）和重构的回波降噪方法，首先对脉冲激光目标回波波形进行建模，然后分析了现有数字化回波降噪算法的性能及其对定位精度的影响。实验结果表明，所提方法可以准确提取目标峰值点位置，改善激光测距机的目标定位精度。

Target echo denoising algorithm of airborne platform multi pulse laser rangefinder under low SNR

For long-distance aircraft targets, airborne multi pulse laser rangefinders usually adopt digital processing system. The factors that affect the ranging accuracy include the range resolution of emitting laser pulse width, the waveform broadening caused by atmospheric propagation and target reflection characteristics, the nonlinear phase frequency characteristics of echo signal receiving and processing channel, etc. Digital sampling rate, echo signal denoising and target waveform peak point position estimation usually cause large target range positioning error. In this paper, an echo denoising method based on Empirical Mode Decomposition(EMD) and reconstruction was proposed. Firstly, the echo waveform of pulse laser target was modeled, and then the performance of existing digital echo denoising algorithms and its influence on positioning accuracy were analyzed. The experimental results show that the proposed method can accurately extract the target peak point position and improve the target positioning accuracy of laser rangefinder.