Hua Kangjian, Liu Bo, Fang Liang, Wang Huachuang, Chen Zhen, Yu Yang
Appl Opt. 2020 Mar 20;59(9):2797-2809. doi: 10.1364/AO.385592.
Backscatter has significant influence on detection efficiency for underwater lidar, especially for coaxial photon-counting lidar using a Geiger-mode avalanche photodiode. In this paper, based on our underwater coaxial photon-counting lidar structure and volume scatter function, a detection model with consideration of backscatter and refraction indices is proposed. Using this detection model, analysis of the detection efficiency is conducted. It reveals that in an underwater environment, higher pulse energy or a closer target range is not necessarily helpful for a higher target detection probability, which is vastly different from our traditional concepts. For example, the detection probability for a 5 m target would be 0.76 using a 200 pJ pulse and 0.55 using a 1000 pJ pulse for our coaxial photon-counting lidar. Monte Carlo simulation is conducted to verify our model and analysis, and some practical methods for improving the target detection probability in an underwater environment are proposed.
后向散射对水下激光雷达的探测效率有显著影响，特别是对于使用盖革模式雪崩光电二极管的同轴光子计数激光雷达。本文基于我们的水下同轴光子计数激光雷达结构和体积散射函数，提出了一种考虑后向散射和折射率的探测模型。利用该探测模型，对探测效率进行了分析。结果表明，在水下环境中，较高的脉冲能量或较近的目标距离不一定有助于提高目标探测概率，这与我们的传统观念有很大不同。例如，对于我们的同轴光子计数激光雷达，使用200 pJ脉冲时，5 m目标的探测概率为0.76，使用1000 pJ脉冲时为0.55。进行了蒙特卡罗模拟以验证我们的模型和分析，并提出了一些在水下环境中提高目标探测概率的实用方法。
