scholarly journals Validation of high-precision effects of a movable riverbed simulation using unmanned aerial vehicles and structure from motion

2018 ◽  
Vol 40 ◽  
pp. 02055
Author(s):  
Masatoshi Denda
Keyword(s):  
Unmanned Aerial Vehicles ◽  
High Precision ◽  
Structure From Motion ◽  
Vegetation Dynamics ◽  
Dynamic Models ◽  
High Accuracy ◽  
River Morphology ◽  
Observation Data ◽  
Dynamics Model ◽  
Vegetation Dynamic

For advanced and strategic management of gravel riverbed restoration and stopping of woodland overgrowth, movable riverbed simulations and vegetation dynamic models that can describe a ‘detailed riverbed materials’ transport’ influencing the vegetation dynamics and estimate the creation area of a gravel riverbed are required. As first steps we verified the hypothesis whether high-accuracy observation data using UAV and SfM improve the accuracy of water flow condition and movable riverbed simulation that can describe the riverbed materials’ transport in detail. In the results, High-precision river morphology using UAVs offers the ability to improve the movable riverbed simulation. And these progresses indicated possibilities of UAV and SfM to develop vegetation dynamics model considering the riverbed materials’ transport.

scholarly journals Relative Status Determination for Spacecraft Relative Motion Based on Dual Quaternion

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jun Sun ◽  
Shijie Zhang ◽  
Xiande Wu ◽  
Fengzhi Guo ◽  
Yaen Xie
Keyword(s):  
Relative Motion ◽  
Dynamic Models ◽  
Attitude Determination ◽  
System State ◽  
Dual Quaternion ◽  
Dynamics Model ◽  
Navigation Problem ◽  
Spacecraft Formation ◽  
Navigation Algorithm ◽  
Relative Status

For the two-satellite formation, the relative motion and attitude determination algorithm is a key component that affects the flight quality and mission efficiency. The relative status determination algorithm is proposed based on the Extended Kalman Filter (EKF) and the system state optimal estimate linearization. Aiming at the relative motion of the spacecraft formation navigation problem, the spacecraft relative kinematics and dynamics model are derived from the dual quaternion in the algorithm. Then taking advantage of EKF technique, combining with the dual quaternion integrated dynamic models, considering the navigation algorithm using the fusion measurement by the gyroscope and star sensors, the relative status determination algorithm is designed. At last the simulation is done to verify the feasibility of the algorithm. The simulation results show that the EKF algorithm has faster convergence speed and higher accuracy.

scholarly journals Brief Communication: Mapping river ice using drones and structure from motion

2018 ◽  
Vol 12 (2) ◽  
pp. 627-633 ◽  
Author(s):  
Knut Alfredsen ◽  
Christian Haas ◽  
Jeffrey A. Tuhtan ◽  
Peggy Zinke
Keyword(s):  
Structure From Motion ◽  
Low Cost ◽  
Cold Climate ◽  
River Ice ◽  
River Morphology ◽  
Ice Thickness ◽  
Surface Model ◽  
Engineering Data ◽  
Site Access ◽  
Remote Sensing Methods

Abstract. In cold climate regions, the formation and break-up of river ice is important for river morphology, winter water supply, and riparian and instream ecology as well as for hydraulic engineering. Data on river ice is therefore significant, both to understand river ice processes directly and to assess ice effects on other systems. Ice measurement is complicated due to difficult site access, the inherent complexity of ice formations, and the potential danger involved in carrying out on-ice measurements. Remote sensing methods are therefore highly useful, and data from satellite-based sensors and, increasingly, aerial and terrestrial imagery are currently applied. Access to low cost drone systems with quality cameras and structure from motion software opens up a new possibility for mapping complex ice formations. Through this method, a georeferenced surface model can be built and data on ice thickness, spatial distribution, and volume can be extracted without accessing the ice, and with considerably fewer measurement efforts compared to traditional surveying methods. A methodology applied to ice mapping is outlined here, and examples are shown of how to successfully derive quantitative data on ice processes.

Experience and results obtained at the ESRF with high-precision air bearing motion systems

2011 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
P. Marion ◽  
L. Ducotte ◽  
M. Nicola ◽  
H. P. van der Kleij ◽  
L. Eybert ◽  
...  
Keyword(s):  
High Precision ◽  
High Accuracy ◽  
Air Bearing ◽  
Air Bearings ◽  
Positioning Accuracy ◽  
Point Of Interest ◽  
Air Film

In high-accuracy motion stages, the positioning accuracy at the point of interest is strongly influenced by guiding errors: for translation motions, straightness errors and angular errors (pitch, yaw and roll); for rotation motions, axial, radial and tilt errors. When air bearings are used for guiding, the air film averages out local irregularities of bearings surfaces, which helps reduce guiding errors considerably. Some results obtained with air bearing precision systems designed and manufactured by specialized companies and tested at ESRF are described below.

Autonomous Unmanned Aerial Vehicle for Post-Disaster Management With Cognitive Radio Communication

2021 ◽  
Vol 12 (1) ◽  
pp. 29-52
Author(s):  
Raja Guru R. ◽  
Naresh Kumar P.
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Processing Technique ◽  
High Accuracy ◽  
Image Processing Technique ◽  
Radio Communication ◽  
Dynamic Changes ◽  
General Graph ◽  
Vision Based Navigation ◽  
Aerial Vehicle ◽  
Post Disaster

Unmanned aerial vehicles (UAV) play a significant role in finding victims affected in the post-disaster zone, where a man cannot risk his life under a critical condition of the disaster environment. The proposed design incorporates autonomous vision-based navigation through the disaster environment based on general graph theory with dynamic changes on the length between two or multiple nodes, where a node is a pathway. Camera fixed on it continuously captures the surrounding footage, processing it frame by frame on-site using image processing technique based on a SOC. Identifies victims in the zone and the pathways available for traversal. UAV uses an ultrasonic rangefinder to avoid collision with obstacles. The system alerts the rescue team if any victim detected and transmits the frames using CRN to the off-site console. UAV learns navigation policy that achieves high accuracy in real-time environments; communication using CRN is uninterrupted and useful during such emergencies.

The Construction Basis of High-Precision Optical Range Finder GD-j1(l)

2018 ◽  
Vol 931 ◽  
pp. 681-686
Author(s):  
Hovsep S. Petrosyan ◽  
Yegisabeth H. Hayrapetyan ◽  
Hovnan A. Hunanyan
Keyword(s):  
High Precision ◽  
Linear Measurement ◽  
High Accuracy ◽  
Compensation Method ◽  
Interference Method ◽  
Modulation Method ◽  
Range Finder ◽  
Optical Range ◽  
Linear Measurements ◽  
Measurement Devices

The methods of construction of high-precision rangefinder on the modulation method, which will complement the means of linear measurements on the interference method, are considered. The linearly compensation method, which leads to the possibility of implementing range finders with an error of mφ=0.01 mm, is proposed as the basic constructions of extremely high accuracy linear measurement devices.

scholarly journals Accurate Landing of Unmanned Aerial Vehicles Using Ground Pattern Recognition

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1532 ◽  
Author(s):  
Jamie Wubben ◽  
Francisco Fabra ◽  
Carlos T. Calafate ◽  
Tomasz Krzeszowski ◽  
Johann M. Marquez-Barja ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Unmanned Aerial Vehicles ◽  
High Precision ◽  
Low Cost ◽  
Target Position ◽  
Flight Behavior ◽  
Ground Pattern ◽  
Aerial Vehicles ◽  
Exact Position ◽  
Precision Landing

Over the last few years, several researchers have been developing protocols and applications in order to autonomously land unmanned aerial vehicles (UAVs). However, most of the proposed protocols rely on expensive equipment or do not satisfy the high precision needs of some UAV applications such as package retrieval and delivery or the compact landing of UAV swarms. Therefore, in this work, a solution for high precision landing based on the use of ArUco markers is presented. In the proposed solution, a UAV equipped with a low-cost camera is able to detect ArUco markers sized 56 × 56 cm from an altitude of up to 30 m. Once the marker is detected, the UAV changes its flight behavior in order to land on the exact position where the marker is located. The proposal was evaluated and validated using both the ArduSim simulation platform and real UAV flights. The results show an average offset of only 11 cm from the target position, which vastly improves the landing accuracy compared to the traditional GPS-based landing, which typically deviates from the intended target by 1 to 3 m.

High‐Precision, High‐Accuracy Oxygen Isotope Measurements of Zircon Reference Materials with the SHRIMP‐SI

2019 ◽  
Vol 44 (1) ◽  
pp. 85-102 ◽  
Author(s):  
Janaína N. Ávila ◽  
Trevor R. Ireland ◽  
Peter Holden ◽  
Peter Lanc ◽  
Andrew Latimore ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
High Precision ◽  
Reference Materials ◽  
High Accuracy ◽  
Isotope Measurements
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