合成孔径激光成像雷达(VI):时空散斑效应和外差探测信噪比

Synthetic Aperture Imaging Ladar(VI):Space-Time Speckle Effect and Heterodyne Signal-to-Noise Ratio

研究了合成孔径激光成像雷达成像过程中激光散斑效应对于光学外差探测的影响,考虑了光学天线孔径对于散斑的空间平滑效应,特别是提出了时间变化的散斑统计特性并进行了数学分析,因为线性调频激光在一次激光曝光时间过程中激光散斑的花样是变化的。最终给出了考虑时空散斑效应的光子受限外差探测信噪比。

The effect of laser speckle on heterodyne detection for synthetic aperture imaging ladar （SAIL） is investigated. The smooth effect due to the finite aperture of SAIL antenna is considered, and particularly the statistical characteristics of the time-varying speckle pattern is explored and mathematically analyzed, which is caused from the frequency modulation of laser within a single look. As a result, the signal-to-noise ratio of photon-limited heterodyne detection due to the space-time speckle effect is given.