Ansgar Dreier

Ansgar Dreier
University of Bonn | Uni Bonn · Institute of Geodesy and Geoinformation (IGG)

Master of Science

About

14
Publications
1,938
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
43
Citations

Publications

Publications (14)
Article
Full-text available
Purpose The use of UAVs (Unmanned Aerial Vehicles) equipped with sensors such as laser scanners offers an alternative to conventional, labor-intensive manual measurements in agriculture, as they enable precise and non-destructive field surveys. Methods This paper evaluates the use of UAV-based laser scanning (RIEGL miniVUX-SYS) for estimating the...
Article
Full-text available
Assessing the quality of a trajectory is a prerequisite for correctly interpreting and using the trajectory in applications such as kinematic laser scanning. Evaluation is for example done empirically by comparison with a ground-truth trajectory recorded simultaneously. Depending on the measurement and sensor configuration, both trajectories have t...
Article
Full-text available
The article presents a practical method that combines low-cost camera systems with remotely operated vehicles (ROVs) to accomplish a comprehensive but economically feasible underwater survey of large hydropower infrastructures. Typically, inspecting reservoirs entails draining them off to allow for visual inspections, which are time-intensive, pose...
Article
Full-text available
Accurately characterizing vineyard parameters is crucial for precise vineyard management and breeding purposes. Various macroscopic vineyard parameters are required to make informed management decisions, such as pesticide application, defoliation strategies, and determining optimal sugar content in each berry by assessing biomass. In this paper, we...
Article
Due to recent improvements in sensor technology, UAV-based laser scanning is nowadays used in more and more applications like topographic surveying or forestry. The quality of the scanning result, a georeferenced 3D point cloud, mainly depends on errors coming from the trajectory estimation, the system calibration and the laser scanner itself. Due...
Conference Paper
Full-text available
The use of UAV-based laser scanning systems is increasing due to the rapid development in sensor technology, especially in applications such as topographic surveys, agriculture or forestry. This paper addresses the quality analysis of direct georeferencing of a UAV-based laser scanning system and further the investigation of scan characteristics of...
Article
Many applications today require the precise determination of the position and orientation of a moving platform over time. However, especially in safety-critical areas, it is also important to derive quality characteristics of the trajectory estimation. This allows verification that sensors are operating within the precision and accuracy required fo...
Conference Paper
Full-text available
The use of unmanned aerial vehicles (UAV) in monitoring applications is constantly increasing due to the improvement in sensor technology and the associated higher accuracy that can be achieved. As a result, UAV-based laser scanning is already being used in various deformation monitoring applications such as the monitoring of landslides or land def...
Article
Full-text available
The use of UAV-based laser scanning systems is increasing due to the rapid development in sensor technology, especially in applications such as topographic surveys or forestry. One advantage of these multi-sensor systems is the possibility of direct georeferencing of the derived 3D point clouds in a global reference frame without additional informa...
Article
Im Bereich der GNSS-Positionierung zählen stationsspezifische Abweichungen, welche aufgrund der Antennenumgebung entstehen, zu den genauigkeitsbegrenzenden Faktoren. In diesem Beitrag wird eine Strategie zur Satellitenselektion vorgestellt, die stationsabhängige Einflüsse, wie die Signalbeugung, den Empfang von Signalen nicht direkt sichtbarer Sate...
Article
In the area of GNSS positioning, site-dependent errors, which are caused by the antenna environment, are one of the accuracy limiting factors. In this paper a strategy for satellite selection is presented, which considers site-dependent effects like signal diffraction, Non-line-of-sight (non-line-of-sight, NLOS) reception and far-field multipath. T...
Conference Paper
Full-text available
In vielen geodätischen Anwendungsbereichen, wie bspw. Überwachungsmessungen, Referenzstationsnetzwerken oder auch kinematischen Vermessungsaufgaben, werden hochgenaue Koordinaten einer statischen oder sich bewegenden GNSS-Antenne benötigt. In diesem Zusammenhang stellen stationsspezifische Abweichungen oftmals den genauigkeitsbegrenzenden Faktor da...
Poster
Full-text available
The positions of the radio sources in the ICRF2 catalog, representing the current realization of the Celestial Reference Frame (CRF), are given as a time invariant coordinate pairs. However, failing to acknowledge systematics within the source positions inevitably leads to a deterioration in the quality of the frame, and thus in all derived variabl...

Network

Cited By