无人机载雷达在冰厚及冰层结构探测中的应用

Application of UAV radar in survey of ice thickness and ice structure

为提高黄河冰厚测量效率,利用无人机载雷达对黄河内蒙古什四份子弯道进行了冰厚测验,并与人工实测冰厚进行了对比,描述了冰层典型特征雷达图谱.结果表明:弯道冰厚分布不均匀,整体冰厚40~80 cm,纵向冰厚沿程逐渐减小,弯顶处冰厚最小,横向冰厚凹岸侧大于凸岸侧,清沟断面冰厚呈小-大-小趋势,靠近水面位置冰厚最小;立封区测验效果一般,雷达测量结果大于人工测量结果,误差在10%左右,平封处精度良好,误差在5%以下,雷达与人工对冰厚走向的测量结果基本一致;雷达波在冰层中传播速度为15~17 cm/ns;雷达图谱可以反映冰层结构,确定裂缝的走向、位置,平立封冰盖的雷达图谱差别较大.无人机载雷达能快速对一定区域的冰厚进行连续测量,极大地提升了小范围冰厚的测验效率,为分析黄河冰的冻融过程、冰层结构提供了技术参考,是一种较为理想的冰层探测方法.

In order to improve the measurement efficiency of ice thickness in the Yellow River,the UAV radar was used to detect the ice thickness in the Shisifenzi bend of the Yellow River in Inner Mongolia.The results were compared with the measured ice thickness,and the characteristics of the typical radar images of the ice layer were analyzed as well.The results show that the ice thickness of the Shensifenzi bend is uneven,and the ice thickness is between 40 cm and 80 cm.Longitudinally,the ice thickness decreases,and the minimum thickness is located at the apex of the bend.The ice thickness on the concave bank is larger than that on the convex bank,the ice thickness of open water area presents a small-large-small trend,and the ice thickness near the water surface is smallest.For the measurement effect,the vertical frozen area is general,the result of radar measurement is greater than that of the manual measurement,the error is about 10%.The flat frozen ice sheet is fine,and the error is less than 5%.The radar measurement results and the manual measurement results have a strong consistency on the trend of the ice thickness,and the propagation velocity of radar wave in the ice layer is between 15—17 cm/ns.Radar images could reflect the structure,position and direction of the ice cracks in ice layer,and the radar images of flat frozen ice sheet and vertical frozen ice sheet are quite different.The UAV radar can quickly measure the ice thickness,which greatly improves the test efficiency of ice thickness in small areas.It provides a technical reference for the analysis of the freezing-thawing process of the ice and the structure under the ice in the Yellow River,which is an ideal method for ice detection.