Land, Water, Air

Author: Benjamin Federmann, May 2016

The gravel quarry of Knobel-Bau also includes two artificial lakes which were surveyed with a specially-equipped boat for hydrographic surveys. What was missing, though, was an aerial view of the entire quarry. Focusing on surveying engineering technologies, IngenieurTeam GEO was contracted to determine the remaining volume in Knobel-Bau’s quarries. By creating georeferenced orthophotos and digital terrain models using the unmanned aerial vehicle (UAV) from Leica Geosystems, the firm was able to present the current situation in detail and provide an effective inventory reduction plan. Using the airborne data, the engineers had the possibility to precisely record areas that were difficult to access and include riparian regions and to the calculation.

For this residual volume calculation of Knobel-Bau GmbH gravel pits, especially geo-referenced orthophotos and digital terrain models provided a good visualisation of the measurement and calculation results. The airborne data was generated by using Leica Geosystems UAV solution.

“有了这个详细的历史overview, our customer can coordinate the extraction processes more precisely,” said Martin Schwall, owner and managing director of IngenieurTeam GEO. “This enables the customer to securely plan what to do with the remaining material, based on the most current and accurate information available.”

Combining to overcome unique challenges

A longtime user of Leica Geosystems levelling and GNSS instruments, IngenieurTeam GEO first became interested in UAV technology when it became part of Leica Geosystems portfolio in 2014. Streamlining surveying components into a fast and efficient process for projects was a key factor in pursuing UAVs for spatial data collection.

“The accuracy of the collected data is important to us, but also the reliability, functionality and quality of all surveying equipment,” said Schwall. “We decided to use this UAV for its trusted reputation in the industry. We then trained one of our employees to become a professional pilot, and we’ve been able to expand our business. Since his training and certification, we not only offer surveying services on land and water but also from the air.”

提取地点的空中调查，包括其人工湖泊，以及使用特殊调查船对水的同时进行水文调查提出了特定的挑战。对于这个特定项目至关重要，必须精确协调这两个任务，以便为Kobel-Bau提供准确的信息。

Flying high, measuring low

创建问题最常见的数据集t deliverable, the various survey methods had to be linked, which required technical solutions and the pilot’s expertise to generate reliable data. To obtain this, the firm devised an exact flight plan using specially developed flight planning software. Using an overview map, a waypoint flight plan facilitated precise planning of the autonomously conducted aerial survey.

“The open interface of the workflow provides us with top quality data with virtually no loss,” said Schwall. “We could then easily combine the aerial and hydrography data seamlessly for one valuable deliverable.”

在确定了高度可见和合适的地面点以供数据进行地理作用之后，进行了空中调查。每次飞行后能够立即查看生成的数据（用高分辨率紧凑型相机拍摄的图片）的能力，调查质量得到了迅速验证。该相机固定在飞行多传感器平台的自由浮动的阳性上，使飞行员和其他人在无人机在地面上就可以立即审查摄影材料。图像在航向飞行期间自动添加，并用无人机生成的GPS坐标标记。

Calculations showed the project would need five flights each lasting six minutes to cover the 55 hectare area. The flight altitude for this kind of topography was established at 90 meters. Due to the wind conditions of the area on the day of the survey, the pilot decided to carry out a total of seven individual flights. As a responsible UAV owner, IngenieurTeam GEO flies the UAV in conditions of a maximum wind speed of 6 m/s to ensure safety.

Trouble-free, all collected data could be combined to form a highly precise model. The areas surveyed with Leica Geosystems total stations, as well as the sonar results of the surveying vessel, merged seamlessly together with orthographic photographs of the UAV.

Combined with the results from the hydrography survey, IngenieurTeam GEO was able to provide a complete overview of the site and the current situation, which Knobel-Bau used to further its business.

“从空中，地面和测量船上的调查数据结合起来，导致了极好的结果。Orthophoto，确切的体积计算和砾石坑的3D模型允许对实际情况进行预期计划，并准确评估。” Knobel-Bau董事总经理Michael Knobel说。“与所有常规和传统方法相比，大型项目的经济实施以及Ingenieurteam Geo的相关结果是决定性的。”

A growing potential

After more than 45 aerial projects and about 350 individual flights, IngenieurTeam GEO continues to be impressed by the data accuracy of Leica Geosystems UAV while seeing nothing but positive ROI on its investment.

“Using Leica Geosystems UAV for aerial data generation has allowed us already to reduce our outdoor process times from entire days to hours or even minutes,“ said Schwall. “We consider the interlinking of different Leica Geosystems technologies and the interaction between software and survey instruments to be the crucial difference to classical surveying methods and commercially available photo drones. This combo makes it easy for us to generate data and to provide our customers with essential information.”