用测深痛保护人和财产

作者：Renata Barradas Gutiérrez

日本是一个大型群岛，位于一个活跃的融合区域，毗邻太平洋一侧的深沟，以及日本海的许多断层和峡谷。由于其地理和复杂的地形，日本是地球上最暴露的自然危害国家之一，例如海平面上升，洪水，地震和海啸。人口增长，气候变化和经济发展，此外，正在威胁人们，基础设施以及位于几条河流和海岸平原的生态系统。

尽管它大大暴露于危险，但在2016年世界风险报告中排名为17^th日本大多数容易发生的灾难风险国家通过调整长期准备策略并采取行动来了解其地形和环境，从而降低了其脆弱性。

Aero Asahi Corp（AAC）的使命是使用最新的硬件和软件技术来保护生命和财产免受任何灾难或事件。这家航空和空间信息服务公司意识到，在未来灾难的情况下，需要数据来减轻风险。为了支持灾难管理和预防，维护基础设施和地图属性，AAC使用移动映射，空中照片调查以及LIDAR地形和测深量调查。

在执行任务

Rivers in Japan, directly managed by the government, have a total length of approximately 8,800 kilometres and are characterised by a deep V-shaped rinsing from steep forests. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) manages and monitors the rivers of the Nippon country. To monitor the river bed deformation every 200-metre pitch, MLIT used in the past an echo sounder performing cross-sectional terrain surveys every five years on the major rivers. To防止灾难并加快任何恢复努力，AAC现在提供了测深和地形数据和地图to MLIT’s river management bureau.

AAC使用Leica Chiroptera II测深和地形LIDAR传感器精确，安全地收集数据，该传感器安装在直升机中，仅需几分钟即可覆盖大面积。Chiroptera II的近红外（NIR）波长用于地形和用于测深的数据收集的绿色波长，使团队可以在浅水区和内陆淡水体中绘制和测量深度，例如河流和湖泊以及周围的洪水泛滥。

“We collect and analyse all the precise data to provide information ready to use, such as deformation, sediment, cross sections, erosions, and bank height for management authorities. Since the Chiroptera II combines a topographic and bathymetric lidar, we can seamlessly measure from water to land – this is particularly useful when rivers are running浅，”AAC空降行动副局长Hiroshi Isobe说。

AAC improved the approach used in the past by complementing the data captured with Chiroptera II with an in-house solution – an echo sounder “Underwater Inspector.” The team tested this approach on the government-controlled rivers in Japan. This combined survey helped the team to create aseamless dense point cloud regardless of the water depth, turbidity, colour, temperature and PH of the river。

The perks of attaching a LiDAR sensor to a helicopter

Mountains cover 73 per cent of the land of the rising sun. When performing aerial surveys in mountainous terrain, AAC attachesChiroptera II到AS350-B3直升机的背面，垂直稳定器的顶部具有GNSS天线，以获得具有较高密度的地理参与点云。AAC is convinced that the variable airspeed, the flexible base location, the shorter turning time and the very low-altitude that can be flown with a helicopter is preferable than the quieter flight with long range and extended flight time that a fixed wing plane provides.

“点云获取速度慢的窝点er. Flying with a helicopter allows us to collect water depth where a swath boat with an echo sounder cannot enter and control the altitude along the Japanese steep terrains,”Isobe说。

Multiple applications

A wide range of deliverables like digital surface and地形模型，分类点云，正吞和GIS层can be created using Chiroptera II’s collected data to develophydrological models to analyse the water flows, drainage management, flood control and support land planning activities。专家团队使用Leica Lidar调查工作室（LSS）来了解河流的地形并创建准确的风险分析。

The periodical cross-sectional survey AAC provides can be used for a wide variety of applications including:

• 洪水映射
• 环境建模和监视
• 可视化河床变形地面和水下
• 得出流量
• Accuracy controls for water level applications.

预测不可预测的

为了保护生活在水体附近的人群，需要研究河流及其周围地区的地形，以监测变化并预测在不同条件下水体的行为。空气传播的激光雷达测深是一种有效的方法survey even in hazardous areas and turbid waters, creating accurate and precise models of coastal and inland water bodies。

“从空中激光调查获得的详细地形数据用于模拟洪水，并每小时预测洪水的传播方式。分析了仿真结果和基础设施信息图，以提供危机管理的最佳数据，例如疏散路线，疏散避难所和受影响的人口。此外，洪水期间航拍照片的立体匹配用于分析表面流量和流动方向，”结论是尤比特。