Laser backscattering characteristics of ship wake bubble target
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摘要:
为了提高 光尾流制导距离和探测信噪比，研究不同距离、不同气泡尺度、不同气泡数密度和不同气泡层厚度的气泡目标的后向散射特性具有重要的理论和应用价值。采用蒙特卡洛仿真和室内实验研究了前述舰船尾流气泡目标的 后向散射特性。结果表明：近距离的气泡要比远距离的气泡更容易被检测到；在气泡数密度为102~108 m−3，气泡层厚度大于0.05 m时，大尺度和小尺度气泡始终存在回波信号，气泡层厚度小于0.05 m时无回波信号，此时，气泡层厚度特性对气泡后向散射的影响最大；在气泡数密度为109 m−3，气泡层厚度为0.05 m以下时，大尺度气泡回波信号脉冲宽度会展宽。在这种情况下，气泡数密度和尺度特性对气泡后向散射的影响最大。搭建了水下典型气泡尺度下的 后向散射测量系统，验证了不同舰船尾流气泡目标特性对 后向探测系统的影响。本文研究成果可为舰船尾流 探测工程提供支撑。
Abstract:In order to improve the laser wake guidance distance and the detection signal-to-noise ratio, it is of great theoretical and practical value to study the backscattering characteristics of bubble targets with different distances, bubble sizes, bubble number densities, and bubble layer thicknesses. The laser backscattering characteristics of ship wake bubble targets with different distances, scales, numerical densities, and thicknesses are studied using Monte Carlo simulations and indoor experiments. When the bubble density is 102−108 m−3 and the thickness of the bubble layer is greater than 0.05 m, there is always an echo signal for both large- and small-scale bubbles. When the thickness of the bubble layer is less than 0.05 m, no echo signal is detected. At this situation, the thickness of the bubble layer is the greatest impact factor on the backward scattering of bubbles. When the bubble number density is 109 m−3 and the thickness of the bubble layer is below 0.05 m, the pulse width of the large-scale bubble echo signal widens. The number density and scale characteristics of the bubbles have the greatest impact on the backscattering of bubbles. A laser backscattering measurement system at the scale of typical underwater bubbles is built to verify the influence of different ship wake bubble characteristics on the laser backscattering detection system, which can provide support for the ship wake laser detection project.
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Key words:
- ship wake /
- Monte Carlo /
- backscattering /
- target characteristics
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图 1 单个光子两次碰撞散射坐标系
Figure 1. Coordinate systems for single photon double collision scattering
图 3 不同距离下气泡后向散射回波信号
Figure 3. Backscattering echo signal of bubble under different distances
图 4 不同气泡密度下的后向散射回波信号
Figure 4. Backscattering echo signal of bubble under different bubble densities
图 5 不同气泡厚度下的后向散射回波信号
Figure 5. Backscattering echo signal of bubble under different bubble thicknesses
图 6 不同气泡尺寸下的后向散射回波信号
Figure 6. Backscattering echo signal of bubble with different bubble sizes
图 7 不同气泡目标特性下的后向散射回波信号
Figure 7. Backscattering echo signals with different bubble target characteristrics
图 9 (a) 不同气泡距离和(b)不同气泡层厚度下的气泡 后向散射信号强度
Figure 9. Laser backscattering signal intensities under (a) different bubble distances and (b) different bubble thicknesses
图 10 不同气泡厚度和数密度下水体回波峰值幅度
Figure 10. Peak echo amplitude of water body under different bubble thicknesses and different densities
图 11 (a) 不同气泡距离；(b) 不同气泡数密度；(c) 不同气泡层厚度下的水体 后向散射信号强度
Figure 11. Laser backscattering signal intensities of water body under (a) various bubble distances, (b) different bubble densities and (c) different bubble thicknesses
图 12 不同距离下水体 后向散射信号变化。（a）峰值幅度；（b）脉冲宽度
Figure 12. Variation of laser backscattering signal of water body at different distances. (a) Signal peak amplitude; (b) pulse width
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