基于射线跟踪算法的舰船尾迹波红外特征与探测

舰船驶过海面后会形成一条长度可达数千米且持续很长时间的尾迹区。这种显著特征为利用尾迹波的红外特征来探测舰船提供了依据。从舰船尾迹区特点出发,实现了尾迹波的可视化仿真。在Cook-Torrance光照模型的基础上建立了适用于舰船尾迹波的红外成像模型。采用射线跟踪算法,并综合考虑太阳辐射、天空背景辐射和大气传输等环境因素的影响,得到了不同探测条件下舰船尾迹波的红外成像特征。结果表明:俯仰角较小时海面整体较暗,舰船尾迹波特征明显;俯仰角较大时海面整体较亮,舰船尾迹波特征减弱;开尔文尾迹的成像特征受气温变化影响较小,湍流尾迹在低俯仰角低气温时为一条暗带,高气温时为一条亮带;海面风速增加,开尔文尾迹最终会无法分辨,湍流尾迹成为唯一可识别的舰船尾迹波特征。

Infrared characterization and detection of ship wake based on ray tracing method

When the ship sails on the sea, a wake of several kilometers length and long continuous time will appear behind the ship. The bases for detecting ship through the infrared characterization of wake are provided by the apparent feathers of ship wake. Visible simulation of wake was achieved from the characterization of ship wake. An infrared imaging model of ship wake was established based on Cook-Torrance model. The infrared imaging characterization under different detecting conditions was obtained with ray tracing method, considering the environment influence of solar radiation, sky background radiation and atmospheric transmission comprehensively. Results indicate that, sea surface is integrally dark and ship wake is apparent at low elevation angle while the sea surface bright and ship wake weak at high elevation angle; the imaging characterization of Kelvin wake is weakly affected by air temperature, and turbulent wake is a dark band at low elevation angle and air temperature but a bright band at high air temperature; Kelvin wake will be eventually unrecognizable with increasing sea surface wind velocity, then the turbulent wake is the only ship wake characterization that can be recognized.