scholarly journals Light and shadow in mapping alpine snowpack with unmanned aerial vehicles in the absence of ground control points

2021 ◽  
Author(s):  
Jesús Revuelto ◽  
Juan Ignacio López Moreno ◽  
Esteban Alonso González
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Ground Control ◽  
Control Points ◽  
Ground Control Points ◽  
Aerial Vehicles ◽  
Light And Shadow

scholarly journals UAV PHOTOGRAMMETRY IMPLEMENTATION TO ENHANCE LAND SURVEYING, COMPARISONS AND POSSIBILITIES

2016 ◽  
Vol XLII-2/W2 ◽  
pp. 107-114 ◽  
Author(s):  
R. El Meouche ◽  
I. Hijazi ◽  
P. A. Poncet ◽  
M. Abunemeh ◽  
M. Rezoug
Keyword(s):  
Unmanned Aerial Vehicles ◽  
3D Modeling ◽  
Maximum Error ◽  
Ground Control ◽  
Control Points ◽  
Ground Control Points ◽  
Area Of Interest ◽  
Aerial Vehicles ◽  
Land Surveying ◽  
Archeological Site

The use of Unmanned Aerial Vehicles (UAVs) for surveying is now widespread and operational for several applications – quarry monitoring, archeological site surveys, forest management and 3D modeling for buildings, for instance. UAV is increasingly used by land surveyors especially for those kinds of projects. It is still ambiguous whether UAV can be applicable for smaller sites and property division. Therefore, the objective of this research is to extract a vectorized plan utilizing a UAV for a small site and investigate the possibility of an official land surveyor exploiting and certificating it. To do that, two plans were created, one using a UAV and another utilizing classical land surveyor instruments (Total Station). A comparison was conducted between the two plans to evaluate the accuracy of the UAV technique compared to the classical one. Moreover, other parameters were also considered such as execution time and the surface covered. The main problems associated with using a UAV are the level of precision and the visualization of the whole area. The results indicated that the precision is quite satisfactory with a maximum error of 1.0 cm on ground control points, and 4 cm for the rest of the model. On the other hand, the results showed that it is not possible to represent the whole area of interest utilizing a UAV, due to vegetation.

scholarly journals Analysis of the impacts on the quality of UAV photogrammetric products

2020 ◽  
Vol 64 (04) ◽  
pp. 489-507
Author(s):  
Mojca Kosmatin Fras ◽  
Urška Drešček ◽  
Anka Lisec ◽  
Dejan Grigillo
Keyword(s):  
Data Acquisition ◽  
Unmanned Aerial Vehicles ◽  
Spatial Data ◽  
Point Clouds ◽  
Ground Control ◽  
Control Points ◽  
Positional Accuracy ◽  
Ground Control Points ◽  
Aerial Vehicles

Unmanned aerial vehicles, equipped with various sensors and devices, are increasingly used to acquire geospatial data in geodesy, geoinformatics, and environmental studies. In this context, a new research and professional field has been developed – UAV photogrammetry – dealing with photogrammetry data acquisition and data processing, acquired by unmanned aerial vehicles. In this study, we analyse the selected factors that impact the quality of data provided using UAV photogrammetry, with the focus on positional accuracy; they are discussed in three groups: (a) factors related to the camera properties and the quality of images; (b) factors related to the mission planning and execution; and (c) factors related to the indirect georeferencing of images using ground control points. These selected factors are analysed based on the detailed review of relevant scientific publications. Additionally, the influence of the number of ground control points and their spatial distribution on point clouds' positional accuracy has been investigated for the case study. As the conclusion, key findings and recommendations for UAV photogrammetric projects are given; we have highlighted the importance of suitable lighting and weather conditions when performing UAV missions for spatial data acquisition, quality equipment, appropriate parameters of UAV data acquisition, and a sufficient number of ground control points, which should be determined with the appropriate positional accuracy and their correct distribution in the field.

scholarly journals Short Communication: Optimizing UAV-SfM based topographic change detection with survey co-alignment

2020 ◽  
Author(s):  
Tjalling de Haas ◽  
Wiebe Nijland ◽  
Brian W. McArdell ◽  
Maurice W. M. L. Kalthof
Keyword(s):  
Change Detection ◽  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Short Communication ◽  
Swiss Alps ◽  
Ground Control ◽  
Control Points ◽  
Classical Approach ◽  
Ground Control Points ◽  
Surface Models

Abstract. High-quality digital surface models (DSMs) generated from structure-from-motion (SfM) based on imagery captured from unmanned aerial vehicles (UAVs), are increasingly used for topographic change detection. Classically, DSMs were generated for each survey individually and then compared to quantify topographic change, but recently it was shown that co-aligning the images of multiple surveys may enhance the accuracy of topographic change detection. Here, we use nine surveys over the Illgraben debris-flow torrent in the Swiss Alps to compare the accuracy of three approaches for UAV-SfM topographic change detection: (1) the classical approach where each survey is processed individually using ground control points (GCPs), (2) co-alignment of all surveys without GCPs, and (3) co-alignment of all surveys with GCPs. We demonstrate that compared to the classical approach co-alignment enhances the accuracy of topographic change detection by a factor 4 with GCPs and a factor 3 without GCPs, leading to xy and z offsets

scholarly journals A Robot Operating System Framework for Secure UAV Communications

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1369
Author(s):  
Hyojun Lee ◽  
Jiyoung Yoon ◽  
Min-Seong Jang ◽  
Kyung-Joon Park
Keyword(s):  
Operating System ◽  
Unmanned Aerial Vehicles ◽  
Ground Control ◽  
Unmanned Aerial System ◽  
Security Framework ◽  
Security Vulnerabilities ◽  
Robot Operating System ◽  
Security Issues ◽  
Aerial Vehicles ◽  
Ground Control Station

To perform advanced operations with unmanned aerial vehicles (UAVs), it is crucial that components other than the existing ones such as flight controller, network devices, and ground control station (GCS) are also used. The inevitable addition of hardware and software to accomplish UAV operations may lead to security vulnerabilities through various vectors. Hence, we propose a security framework in this study to improve the security of an unmanned aerial system (UAS). The proposed framework operates in the robot operating system (ROS) and is designed to focus on several perspectives, such as overhead arising from additional security elements and security issues essential for flight missions. The UAS is operated in a nonnative and native ROS environment. The performance of the proposed framework in both environments is verified through experiments.

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