Airborne Hydrographic LiDAR Mapping-Potential of a new technique for capturing shallow water bodies
Airborne Hydrographic LiDAR Mapping-Potential of a new technique for capturing shallow water bodies
复制标题
机载水文激光雷达测绘——捕捉浅水体新技术的潜力
DOI：
10.36334/modsim.2011.e14.mandlburger
复制
发表时间：
2011
影响因子：
9.2
通讯作者：
N. Pfeifer
中科院分区：
文献类型：
--
作者：
G. Mandlburger;M. Pfennigbauer;F. Steinbacher;N. Pfeifer
在本文中，我们提出了一个水文激光扫描仪（原型仪器）的总体设计，由公司Riegl激光测量系统与因斯布鲁克大学，水利工程单位合作。该仪器使用能够穿透水柱的绿色激光源（λ = 532 nm）。发射非常短的激光脉冲（1 ns），并将后向散射信号数字化，从而在飞行期间和后处理中在线进行复杂的波形处理。与安装在同一平台上的传统地形机载激光扫描仪（λ = 1500 nm）相结合，可以在一次活动中对河岸前陆、水面和河床进行完整的水文和地形测量。与现有的测深激光雷达系统相比，所提出的系统仅使用中等脉冲能量，但高达250 kHz的高脉冲重复率，因此，侧重于在清水条件下对浅水沃茨的详细描述。图一：2011年7月使用实验性Riegl水文激光扫描仪VQ-820-G采集的点云的3D视图本文讨论了不同的应用领域，并介绍了首次真实试飞的结果。它示出：（i）高脉冲重复率使点密度在地面上的水体约。10 - 20点/米，（ii）短激光脉冲与波形处理一起能够区分小于25厘米的水和地面反射，（iii）地形和测深激光扫描仪的组合首次能够在一次测量中获取用于水力建模的几何数据，从而提供更加均匀的数据基础，（iv）高的点密度和小于10 cm的测距精度使得能够详细和精确地描述河床形态，从而为校准和验证泥沙输运模型提供了极好的数据源。该仪器的重点是在清水条件下捕获浅水水体，因此不适用于绘制更广泛的河流（由于悬浮物导致的浑浊水体）。然而，即使对于这些河流，所提出的技术也可以闭合河岸之间的间隙（例如，通过地形LiDAR）和主通道（例如，通过回声探测）。
In this paper, we present the general design of a hydrographic laser scanner (prototype instrument) manufactured by the company Riegl Laser Measurement Systems in cooperation with the University of Innsbruck, Unit of Hydraulic Engineering. The instrument utilizes a green laser source (λ=532 nm) capable of penetrating the water column. Very short laser pulses (1 ns) are emitted and the backscattered signal is digitized enabling sophisticated waveform processing online during the flight and in post processing. In combination with a traditional topographic airborne laser scanner (λ=1500 nm) mounted on the same platform a complete hydrographic and topographic survey of the riparian foreland, the water surface and river bed can be carried out in a single campaign. In contrast to existing bathymetric LiDAR systems, the presented system uses only medium pulse energy but a high pulse repetition rate of up to 250 kHz and, thus, focuses on a detailed description of shallow waters under clear water conditions. Figure 1: 3D-view of the point cloud acquired with the experimental Riegl hydrographic laser scanner VQ-820-G in July 2011 Different fields of applications are discussed in the paper and the results of a first real-world test flight are presented. It is shown that: (i) the high pulse repetition rate enables a point density on the ground of the water body of approx. 10-20 points/m, (ii) the short laser pulses together with waveform processing enable a discrimination between water and ground reflections of less than 25 cm, (iii) the combination of a topographic and bathymetric laser scanner enable, for the first time, the acquisition of the geometry data for hydraulic modeling in a single survey, thus, providing a much more homogeneous data basis, and (iv) the high point density and the ranging accuracy of less than 10 cm enable a detailed and precise description of the river bed morphology, thus, providing an excellent data source for calibrating and validating sediment transport models. With the focus on capturing shallow water bodies under clear water conditions, the instrument is not designed for mapping of broader rivers (turbid water due to suspended material). However, even for these rivers the presented technique can close the gap between the river bank (captured, e.g., by topographic LiDAR) and the main channel (e.g., by echo sounding).