scholarly journals Drone-Based High-Resolution Tracking of Aquatic Vertebrates

Drones ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 37 ◽  
Author(s):  
Vincent Raoult ◽  
Louise Tosetto ◽  
Jane Williamson

Determining the small-scale movement patterns of marine vertebrates usually requires invasive active acoustic tagging or in-water monitoring, with the inherent behavioural impacts of those techniques. In addition, these techniques rarely allow direct continuous behavioural assessments or the recording of environmental interactions, especially for highly mobile species. Here, we trial a novel method of assessing small-scale movement patterns of marine vertebrates using an unmanned aerial vehicle that could complement longer-term tracking approaches. This approach is unlikely to have behavioural impacts and provides high accuracy and high frequency location data (10 Hz), while subsequently allowing quantitative trajectory analysis. Unmanned aerial vehicle tracking is also relatively low cost compared to single-use acoustic and GPS tags. We tracked 14 sharks for up to 10 min in a shallow lagoon of Heron Island, Australia. Trajectory analysis revealed that Epaulette sharks (Hemiscyllium ocellatum) displayed sinusoidal movement patterns, while Blacktip Reef Sharks (Carcharhinus melanopterus) had more linear trajectories that were similar to those of a Lemon shark (Negaprion acutidens). Individual shark trajectory patterns and movement speeds were highly variable. Results indicate that Epaulette sharks may be more mobile during diurnal low tides than previously thought. The approach presented here allows the movements and behaviours of marine vertebrates to be analysed at resolutions not previously possible without complex and expensive acoustic arrays. This method would be useful to assess the habitat use and behaviours of sharks and rays in shallow water environments, where they are most likely to interact with humans.

Author(s):  
Mohammed S. Mayeed ◽  
Gabriel Darveau

In this study a gasoline powered hexa-copter unmanned aerial vehicle (UAV) has been designed as a solution to farmers’ need for a low cost, easy to maintain, long flight duration, and multi-purpose means of specific aerial applications for insecticides and herbicides. Application of herbicides and pesticides by airplane is an example of how farmers have used technology to improve their bottom line and overall quality of life. Fields can now be sprayed in under an hour instead of consuming an entire day. However, if a producer has noxious weeds in only a small area, fixed-wing aerial application cannot be used as it is only accurate enough to do an entire field. Currently there is no solution for small scale, accurate, aerial herbicide application to meet this need. The currently available Yamaha Rmax UAV costs a tremendous amount of money and also requires a lot of money to maintain. Though it may be useful in large scale aerial spraying on the farm land, it would not be used in targeted specific areas as it is not efficient in specific applications. The gasoline powered hexacopter UAV designed in this study is a low cost solution to farmers’ need for specific aerial applications of insecticides and herbicides. The UAV design can carry 2–3 gallons of herbicide (16.7–25.0 lbs.) for a flight time of more than 30 minutes without refueling. The design could be transported in a 60.3in × 56.7in pickup bed. Structural and fatigue analyses are performed on the complete structure using state of the art software SolidWorks Simulation. The minimum factor of safety is obtained to be 10 based on maximum von Mises stress failure criteria. Under normal conditions with an estimated commercial use of 100 cycles per day it is observed that the design would survive for about 13 years without any fatigue failure. A drop test analysis is performed to ensure the design can survive a 5 feet freefall and a frequency analysis is also performed to observe the critical natural frequency of the structure. Flow simulations are performed on the 6 propellers/blades model using state of the art software SolidWorks Flow Simulation to observe the effect of vorticity interactions on the lift force. The design has been reasonably optimized based on maximizing the lift force. With this new UAV design small scale and substantial farmers could afford a personal UAV for aerial applications with a small amount of capital whose absence hindered efficient and effective specific aerial application for many years.


2016 ◽  
Author(s):  
Phillip Harder ◽  
Michael Schirmer ◽  
John Pomeroy ◽  
Warren Helgason

Abstract. The quantification of the spatial distribution of snow is crucial to predict and assess snow as a water resource and understand land-atmosphere interactions in cold regions. Typical remote sensing approaches to quantify snow depth have focused on terrestrial and airborne laser scanning and recently airborne (manned and unmanned) photogrammetry. In this study photography from a small unmanned aerial vehicle (UAV) was used to generate digital surface models (DSMs) and orthomosaics for snowcovers at a cultivated agricultural Canadian Prairie and a sparsely-vegetated Rocky Mountain alpine ridgetop site using Structure from Motion (SfM). The ability of this method to quantify snow depth, changes in depth and its spatial variability was assessed for different terrain types over time. Root mean square errors in snow depth estimation from the DSMs were 8.8 cm for a short prairie grain stubble surface, 13.7 cm for a tall prairie grain stubble surface and 8.5 cm for an alpine mountain surface. This technique provided meaningful information on maximum snow accumulation and snow-covered area depletion at all sites, while temporal changes in snow depth could also be quantified at the alpine site due to the deeper snowpack and consequent higher signal-to noise-ratio. The application of SfM to UAV photographs can estimate snow depth in areas with snow depth > 30 cm – this restricts its utility for studies of the ablation of shallow, windblown snowpacks. Accuracy varied with surface characteristics, sunlight and wind speed during the flight, with the most consistent performance found for wind speeds < 6 m s−1, clear skies, high sun angles and surfaces with negligible vegetation cover. Relative to surfaces having greater contrast and more identifiable features, snow surfaces present unique challenges when applying SfM to imagery collected by a small UAV for the generation of DSMs. Regardless, the low cost, deployment mobility and the capability of repeat-on-demand flights that generate DSMs and orthomosaics of unprecedented spatial resolution provide exciting opportunities to quantify previously unobservable small-scale variability in snow depth and its dynamics.


2020 ◽  
Vol 12 (4) ◽  
pp. 111-125
Author(s):  
Raluca MAIER ◽  
Andrei MANDOC ◽  
Stefan GHERASIM ◽  
Stefan PETCULESCU ◽  
David MANOLACHE ◽  
...  

The present paper aims to develop a small scale Unmanned Aerial Vehicle for railway inspection. The development process and structure manufacturing aimed at a low complexity technological process both to meet market requirements and to be economically efficient. To define the architectural structure and its components in the design process, a NACA 0024 aerodynamic profile was selected out of two proposed airfoils. The novelty of this concept is the double benefit of the wing, which serves as a cargo bay while uses a low-cost manufacturing technology, incorporating the 3D printing process. Further, a simplified preliminary aerodynamic calculation was performed, the model was manufactured using composite materials reinforced with carbon fibre while other key components have been obtained using the 3D printing technology. In the end, the manufacturing process was a success and the unmanned aerial vehicle was designed and manufactured specifically that its flight envelope meets the requirements of the mission.


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4705 ◽  
Author(s):  
Adil Shah ◽  
Joseph Pitt ◽  
Khristopher Kabbabe ◽  
Grant Allen

Point-source methane emission flux quantification is required to help constrain the global methane budget. Facility-scale fluxes can be derived using in situ methane mole fraction sampling, near-to-source, which may be acquired from an unmanned aerial vehicle (UAV) platform. We test a new non-dispersive infrared methane sensor by mounting it onto a small UAV, which flew downwind of a controlled methane release. Nine UAV flight surveys were conducted on a downwind vertical sampling plane, perpendicular to mean wind direction. The sensor was first packaged in an enclosure prior to sampling which contained a pump and a recording computer, with a total mass of 1.0 kg. The packaged sensor was then characterised to derive a gain factor of 0.92 ± 0.07, independent of water mole fraction, and an Allan deviation precision (at 1 Hz) of ±1.16 ppm. This poor instrumental precision and possible short-term drifts made it non-trivial to define a background mole fraction during UAV surveys, which may be important where any measured signal is small compared to sources of instrumental uncertainty and drift. This rendered the sensor incapable of deriving a meaningful flux from UAV sampling for emissions of the order of 1 g s−1. Nevertheless, the sensor may indeed be useful when sampling mole fraction enhancements of the order of at least 10 ppm (an order of magnitude above the 1 Hz Allan deviation), either from stationary ground-based sampling (in baseline studies) or from mobile sampling downwind of sources with greater source flux than those observed in this study. While many methods utilising low-cost sensors to determine methane flux are being developed, this study highlights the importance of adequately characterising and testing all new sensors before they are used in scientific research.


Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2238 ◽  
Author(s):  
Mingjie Liu ◽  
Xianhao Wang ◽  
Anjian Zhou ◽  
Xiuyuan Fu ◽  
Yiwei Ma ◽  
...  

Object detection, as a fundamental task in computer vision, has been developed enormously, but is still challenging work, especially for Unmanned Aerial Vehicle (UAV) perspective due to small scale of the target. In this study, the authors develop a special detection method for small objects in UAV perspective. Based on YOLOv3, the Resblock in darknet is first optimized by concatenating two ResNet units that have the same width and height. Then, the entire darknet structure is improved by increasing convolution operation at an early layer to enrich spatial information. Both these two optimizations can enlarge the receptive filed. Furthermore, UAV-viewed dataset is collected to UAV perspective or small object detection. An optimized training method is also proposed based on collected UAV-viewed dataset. The experimental results on public dataset and our collected UAV-viewed dataset show distinct performance improvement on small object detection with keeping the same level performance on normal dataset, which means our proposed method adapts to different kinds of conditions.


10.14311/754 ◽  
2005 ◽  
Vol 45 (4) ◽  
Author(s):  
P. Kaňovský ◽  
L. Smrcek ◽  
C. Goodchild

The study described in this paper deals with the issue of a design tool for the autopilot of an Unmanned Aerial Vehicle (UAV) and the selection of the airdata and inertial system sensors. This project was processed in cooperation with VTUL a PVO o.z. [1]. The feature that distinguishes the autopilot requirements of a UAV (Figs. 1, 7, 8) from the flight systems of conventional manned aircraft is the paradox of controlling a high bandwidth dynamical system using sensors that are in harmony with the low cost low weight objectives that UAV designs are often expected to achieve. The principal function of the autopilot is flight stability, which establishes the UAV as a stable airborne platform that can operate at a precisely defined height. The main sensor for providing this height information is a barometric altimeter. The solution to the UAV autopilot design was realised with simulations using the facilities of Matlab® and in particular Simulink®[2]. 


2018 ◽  
Vol 159 ◽  
pp. 02045
Author(s):  
Mochammad Ariyanto ◽  
Joga D. Setiawan ◽  
Teguh Prabowo ◽  
Ismoyo Haryanto ◽  
Munadi

This research will try to design a low cost of fixed-wing unmanned aerial vehicle (UAV) using low-cost material that able to fly autonomously. Six parameters of UAV’s structure will be optimized based on basic airframe configuration, wing configuration, straight wing, tail configuration, fuselage material, and propeller location. The resulted and manufactured prototype of fixed-wing UAV will be tested in autonomous fight tests. Based on the flight test, the developed UAV can successfully fly autonomously following the trajectory command. The result shows that low-cost material can be used as a body part of fixed-wing UAV.


Sign in / Sign up

Export Citation Format

Share Document