scholarly journals Advances in mapping sub-canopy snow depth with unmanned aerial vehicles using structure from motion and lidar techniques

2019 ◽  
Author(s):  
Phillip Harder ◽  
John W. Pomeroy ◽  
Warren D. Helgason
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Snow Depth ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Canadian Prairie ◽  
Widespread Application ◽  
Aerial Vehicles ◽  
Wide Range ◽  
Consistent Error

Abstract. Vegetation has a tremendous influence on snow processes and snowpack dynamics yet remote sensing techniques to resolve the spatial variability of sub-canopy snow depth are lacking. Unmanned Aerial Vehicles (UAV) have had recent widespread application to capture high resolution information on snow processes and are herein applied to the sub-canopy snow depth challenge. Previous demonstrations of snow depth mapping with UAV Structure from Motion (SfM) and airborne-lidar have focussed on non-vegetated surfaces or reported large errors in the presence of vegetation. In contrast, UAV-lidar systems have high-density point clouds, measure returns from a wide range of scan angles, and so have a greater likelihood of successfully sensing the sub-canopy snow depth. The effectiveness of UAV-lidar and UAV-SfM in mapping snow depth in both open and forested terrain was tested in a 2019 field campaign in the Canadian Rockies Hydrological Observatory, Alberta and at Canadian Prairie sites near Saskatoon, Saskatchewan, Canada. Only UAV-lidar could successfully measure the sub-canopy snow surface with reliable sub-canopy point coverage, and consistent error metrics (RMSE

scholarly journals Improving sub-canopy snow depth mapping with unmanned aerial vehicles: lidar versus structure-from-motion techniques

2020 ◽  
Vol 14 (6) ◽  
pp. 1919-1935
Author(s):  
Phillip Harder ◽  
John W. Pomeroy ◽  
Warren D. Helgason
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Snow Depth ◽  
Airborne Lidar ◽  
Snow Surface ◽  
Widespread Application ◽  
Large Variability ◽  
Error Metrics ◽  
Aerial Vehicles ◽  
Wide Range

Abstract. Vegetation has a tremendous influence on snow processes and snowpack dynamics, yet remote sensing techniques to resolve the spatial variability of sub-canopy snow depth are not always available and are difficult from space-based platforms. Unmanned aerial vehicles (UAVs) have had recent widespread application to capture high-resolution information on snow processes and are herein applied to the sub-canopy snow depth challenge. Previous demonstrations of snow depth mapping with UAV structure from motion (SfM) and airborne lidar have focussed on non-vegetated surfaces or reported large errors in the presence of vegetation. In contrast, UAV-lidar systems have high-density point clouds and measure returns from a wide range of scan angles, increasing the likelihood of successfully sensing the sub-canopy snow depth. The effectiveness of UAV lidar and UAV SfM in mapping snow depth in both open and forested terrain was tested in a 2019 field campaign at the Canadian Rockies Hydrological Observatory, Alberta, and at Canadian prairie sites near Saskatoon, Saskatchewan, Canada. Only UAV lidar could successfully measure the sub-canopy snow surface with reliable sub-canopy point coverage and consistent error metrics (root mean square error (RMSE) <0.17 m and bias −0.03 to −0.13 m). Relative to UAV lidar, UAV SfM did not consistently sense the sub-canopy snow surface, the interpolation needed to account for point cloud gaps introduced interpolation artefacts, and error metrics demonstrated relatively large variability (RMSE<0.33 m and bias 0.08 to −0.14 m). With the demonstration of sub-canopy snow depth mapping capabilities, a number of early applications are presented to showcase the ability of UAV lidar to effectively quantify the many multiscale snow processes defining snowpack dynamics in mountain and prairie environments.

scholarly journals Efficient Reactive Obstacle Avoidance Using Spirals for Escape

Drones ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 51
Author(s):  
Fábio Azevedo ◽  
Jaime S. Cardoso ◽  
André Ferreira ◽  
Tiago Fernandes ◽  
Miguel Moreira ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Mobile Robotics ◽  
Point Clouds ◽  
Depth Camera ◽  
Main Task ◽  
Robust Method ◽  
Aerial Vehicles ◽  
Correct Execution ◽  
Low Altitude ◽  
High Degree

The usage of unmanned aerial vehicles (UAV) has increased in recent years and new application scenarios have emerged. Some of them involve tasks that require a high degree of autonomy, leading to increasingly complex systems. In order for a robot to be autonomous, it requires appropriate perception sensors that interpret the environment and enable the correct execution of the main task of mobile robotics: navigation. In the case of UAVs, flying at low altitude greatly increases the probability of encountering obstacles, so they need a fast, simple, and robust method of collision avoidance. This work covers the problem of navigation in unknown scenarios by implementing a simple, yet robust, environment-reactive approach. The implementation is done with both CPU and GPU map representations to allow wider coverage of possible applications. This method searches for obstacles that cross a cylindrical safety volume, and selects an escape point from a spiral for avoiding the obstacle. The algorithm is able to successfully navigate in complex scenarios, using both a high and low-power computer, typically found aboard UAVs, relying only on a depth camera with a limited FOV and range. Depending on the configuration, the algorithm can process point clouds at nearly 40 Hz in Jetson Nano, while checking for threats at 10 kHz. Some preliminary tests were conducted with real-world scenarios, showing both the advantages and limitations of CPU and GPU-based methodologies.

scholarly journals Unmanned Aerial Vehicles (UAVs) for Physical Progress Monitoring of Construction

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4227
Author(s):  
Nicolás Jacob-Loyola ◽  
Felipe Muñoz-La Rivera ◽  
Rodrigo F. Herrera ◽  
Edison Atencio
Keyword(s):  
Computer Vision ◽  
Unmanned Aerial Vehicles ◽  
Progress Monitoring ◽  
Residential Building ◽  
Point Clouds ◽  
Construction Site ◽  
Manual Operation ◽  
Work Site ◽  
Aerial Vehicles ◽  
Made In

The physical progress of a construction project is monitored by an inspector responsible for verifying and backing up progress information, usually through site photography. Progress monitoring has improved, thanks to advances in image acquisition, computer vision, and the development of unmanned aerial vehicles (UAVs). However, no comprehensive and simple methodology exists to guide practitioners and facilitate the use of these methods. This research provides recommendations for the periodic recording of the physical progress of a construction site through the manual operation of UAVs and the use of point clouds obtained under photogrammetric techniques. The programmed progress is then compared with the actual progress made in a 4D BIM environment. This methodology was applied in the construction of a reinforced concrete residential building. The results showed the methodology is effective for UAV operation in the work site and the use of the photogrammetric visual records for the monitoring of the physical progress and the communication of the work performed to the project stakeholders.

scholarly journals Internet of Unmanned Aerial Vehicles—A Multilayer Low-Altitude Airspace Model for Distributed UAV Traffic Management

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4779 ◽  
Author(s):  
Nader S. Labib ◽  
Grégoire Danoy ◽  
Jedrzej Musial ◽  
Matthias R. Brust ◽  
Pascal Bouvry
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Traffic Management ◽  
Complex Problem ◽  
Experimental Simulation ◽  
Aerial Vehicles ◽  
Safe Management ◽  
Wide Range ◽  
Abstract Level ◽  
Low Altitude ◽  
New Research

The rapid adoption of Internet of Things (IoT) has encouraged the integration of new connected devices such as Unmanned Aerial Vehicles (UAVs) to the ubiquitous network. UAVs promise a pragmatic solution to the limitations of existing terrestrial IoT infrastructure as well as bring new means of delivering IoT services through a wide range of applications. Owning to their potential, UAVs are expected to soon dominate the low-altitude airspace over populated cities. This introduces new research challenges such as the safe management of UAVs operation under high traffic demands. This paper proposes a novel way of structuring the uncontrolled, low-altitude airspace, with the aim of addressing the complex problem of UAV traffic management at an abstract level. The work, hence, introduces a model of the airspace as a weighted multilayer network of nodes and airways and presents a set of experimental simulation results using three UAV traffic management heuristics.

scholarly journals Optimization of SUAV’s propeller in a hover

2020 ◽  
Vol 313 ◽  
pp. 00045 ◽  
Author(s):  
Jakub Hnidka ◽  
Dalibor Rozehnal ◽  
Karel Maňas
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Propulsion System ◽  
Simple Method ◽  
Widespread Application ◽  
Method Of Calculation ◽  
Propeller Design ◽  
Aerial Vehicles ◽  
Simplified Method ◽  
System Components ◽  
Overall Efficiency

Small unmanned aerial vehicles (SUAVs) have found a widespread application in past decades. However, as the criticality of the missions for which they can be used increases, the demand for improvement of their efficiency increases as well. The paper focuses on a propeller driven SUAVs of a multirotor type, equipped with an electric motor, battery and propeller. The paper presents a simplified method of calculation of the SUAV maximal endurance, if the characteristics of all components of the propulsion system are known. To improve the overall efficiency of the propulsion system of an SUAV, the correct combination of all propulsion system components is critical. However, the largest impact on the maximal endurance is, arguably, caused by the propeller. The paper proposes a simple method of optimizing the propeller characteristics for hover and compares the proposed propeller design with conventional and commercially available propellers.

scholarly journals Operational Framework for Rapid, Very-high Resolution Mapping of Glacial Geomorphology Using Low-cost Unmanned Aerial Vehicles and Structure-from-Motion Approach

2019 ◽  
Vol 11 (1) ◽  
pp. 65 ◽  
Author(s):  
Marek W. Ewertowski ◽  
Aleksandra M. Tomczyk ◽  
David J. A. Evans ◽  
David H. Roberts ◽  
Wojciech Ewertowski
Keyword(s):  
High Resolution ◽  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Low Cost ◽  
Control Point ◽  
Glacial Geomorphology ◽  
High Resolution Mapping ◽  
Aerial Vehicles ◽  
Resolution Mapping ◽  
Very High

This study presents the operational framework for rapid, very-high resolution mapping of glacial geomorphology, with the use of budget Unmanned Aerial Vehicles and a structure-from-motion approach. The proposed workflow comprises seven stages: (1) Preparation and selection of the appropriate platform; (2) transport; (3) preliminary on-site activities (including optional ground-control-point collection); (4) pre-flight setup and checks; (5) conducting the mission; (6) data processing; and (7) mapping and change detection. The application of the proposed framework has been illustrated by a mapping case study on the glacial foreland of Hørbyebreen, Svalbard, Norway. A consumer-grade quadcopter (DJI Phantom) was used to collect the data, while images were processed using the structure-from-motion approach. The resultant orthomosaic (1.9 cm ground sampling distance—GSD) and digital elevation model (7.9 cm GSD) were used to map the glacial-related landforms in detail. It demonstrated the applicability of the proposed framework to map and potentially monitor detailed changes in a rapidly evolving proglacial environment, using a low-cost approach. Its coverage of multiple aspects ensures that the proposed framework is universal and can be applied in a broader range of settings.

US armed UAV precedent will hinder global rules-making

2016 ◽  
Keyword(s):  
United States ◽  
Unmanned Aerial Vehicles ◽  
Policy Reform ◽  
The United States ◽  
Barack Obama ◽  
International Norms ◽  
Content Type ◽  
Intelligence Sharing ◽  
Aerial Vehicles ◽  
Wide Range

Subject Post-Obama armed UAV policy. Significance As President Barack Obama prepares to leave office in January 2017, his administration has called for the United States to lead development of a set of international norms to govern the use of armed UAVs ('unmanned aerial vehicles' or 'drones'). The international proliferation and military use of armed UAVs by nations outside the circle of trusted US allies have highlighted the urgency of formulating clearly articulated international rules to govern an otherwise vaguely defined arena of international behaviour dominated by US precedent. Impacts Congressional aversion to supporting ground interventions abroad will enable the next president further to delay UAV policy reform. A wide range of countries frustrated with restrictions from Washington may turn to China as a key supplier of armed UAVs. Failed US efforts to reform the covert drone programme may complicate intelligence-sharing with European allies.

scholarly journals Analysis of the military application of unmanned aircraft and main direction for their development

2021 ◽  
Vol 33 ◽  
pp. 237-250
Author(s):  
Nikolay Zagorski
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Unmanned Aircraft ◽  
Armed Struggle ◽  
Military Application ◽  
Aerial Vehicles ◽  
Wide Range ◽  
Military Conflicts ◽  
Range Of Functions ◽  
The Military ◽  
Further Development

Modern military unmanned aerial vehicles (UAVs) are assigned a wide range of functions, for the implementation of which they perform many tasks in various military conflicts. The results of the analysis give them the opportunity to reveal the problems in the use of UAVs, make changes in their functions and tasks and identify areas for further development. At present, this requires the introduction of the achievements of artificial intelligence, the introduction of expert systems and microelectronics on board UAVs, as well as their integration with various other means of conducting armed struggle. At the same time, some of the technological solutions for the creation and improvement of UAVs for military purposes can be applied in the civilian sector.

scholarly journals Key wireless communication technologies to support traffic management systems of unmanned aerial vehicles for civil application (review of foreign literature)

2021 ◽  
Vol 24 (2) ◽  
pp. 70-92
Author(s):  
E. A. Vinogradov
Keyword(s):  
Wireless Communication ◽  
Unmanned Aerial Vehicles ◽  
Communication Networks ◽  
Traffic Management ◽  
Communication Technologies ◽  
Unmanned Aircraft ◽  
Civil Aviation ◽  
Aerial Vehicles ◽  
Wide Range ◽  
Aircraft System

Not less than one hundred thousand Unmanned Aerial Vehicles (UAVs) are expected to perform flights simultaneously in Russia by 2035. The UAV fleet capacity triggers the development of the systems for informational support, operating control and management of UAV flights (Unmanned Aircraft System Traffic Management (UTM) systems) similar to that one already operating in manned aviation. The challenges arising in the sphere of civil aviation cannot be solved without wireless communication. The goals of this article are as follows: 1) familiarization of communication experts with the latest scientific developments of unmanned aerial technologies 2) description of the telecommunication-related problems of extensive systems of UAV control encountered by development engineers. In this article a schematic architecture and main functions of UTM systems are described as well as the examples of their implementation. Special emphasis is put on enhancing flight safety by means of a rational choice of communication technologies to manage conflicts (Conflict Management) known as "collision avoidance". The article analyzes the application of a wide range of wireless technologies ranging from Wi-Fi and Automatic Dependent Surveillance Broadcast (ADS-B) to 5G cellular networks as well as cell-free networks contributing to the development of 6G communication networks. As a result of the analysis, a list of promising research trends at the intersection of the fields of wireless communication and UAVs for civil application is made.

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