scholarly journals Environmental and Sensor Integration Influences on Temperature Measurements by Rotary-Wing Unmanned Aircraft Systems

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1470 ◽  
Author(s):  
Brian Greene ◽  
Antonio Segales ◽  
Tyler Bell ◽  
Elizabeth Pillar-Little ◽  
Phillip Chilson
Keyword(s):  
Unmanned Aircraft ◽  
The Body ◽  
Unmanned Aircraft Systems ◽  
Sensor Integration ◽  
Heat Sources ◽  
Aircraft Systems ◽  
Ducted Fan ◽  
Rotary Wing

Obtaining thermodynamic measurements using rotary-wing unmanned aircraft systems (rwUAS) requires several considerations for mitigating biases from the aircraft and its environment. In this study, we focus on how the method of temperature sensor integration can impact the quality of its measurements. To minimize non-environmental heat sources and prevent any contamination coming from the rwUAS body, two configurations with different sensor placements are proposed for comparison. The first configuration consists of a custom quadcopter with temperature and humidity sensors placed below the propellers for aspiration. The second configuration incorporates the same quadcopter design with sensors instead shielded inside of an L-duct and aspirated by a ducted fan. Additionally, an autopilot algorithm was developed for these platforms to face them into the wind during flight for kinematic wind estimations. This study will utilize in situ rwUAS observations validated against tower-mounted reference instruments to examine how measurements are influenced both by the different configurations as well as the ambient environment. Results indicate that both methods of integration are valid but the below-propeller configuration is more susceptible to errors from solar radiation and heat from the body of the rwUAS.

scholarly journals Considerations for temperature sensor placement on rotary-wing unmanned aircraft systems

2018 ◽  
Author(s):  
Brian R. Greene ◽  
Antonio R. Segales ◽  
Sean Waugh ◽  
Simon Duthoit ◽  
Phillip B. Chilson
Keyword(s):  
Frictional Heating ◽  
Sensor Placement ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Heat Sources ◽  
Aircraft Systems ◽  
Series Of Experiments ◽  
Rotary Wing ◽  
Viable Method

Abstract. With their recent surge in commercial accessibility, rotary-wing unmanned aircraft systems (rwUAS) are proving to be a viable method of atmospheric sensing and sampling while improving upon the shortcomings of traditional methods. To maximize the potential for these platforms to provide reliable observations, it is imperative to have an understanding of their strengths and limitations under varying environmental conditions. This study focuses on the quality of measurements relative to sensor locations on board rwUAS. Typically, thermistors require aspiration and proper siting free of heat sources to make representative measurements of the atmosphere. In an effort to characterize ideal locations for sensor placement, a series of experiments were conducted in the homogeneous environment of an indoor chamber with a pedestal-mounted rwUAS. A suite of thermistors along with a wind probe were mounted inside of a solar shield, which was affixed to a linear actuator arm. The actuator arm was configured such that the sensors within the solar shield would travel underneath the platform into and out of the propeller wash. The actuator arm was displaced horizontally underneath the platform while the motors were throttled to 50 percent, yielding a time series of temperature and wind speed which could be compared to temperatures being collected in the ambient environment. Results indicate that temperatures may be biased on the order of 0.5–1.0 °C and vary appreciably without aspiration, sensors placed close to the tips of the rotors may experience biases due to frictional and compressional heating as a result of turbulent fluctuations, and sensors in proximity to motors may experience biases approaching 1 °C. From these trials, it has been determined that sensor placement underneath a propeller on an rwUAS a distance of one quarter the length of the propeller from the tip is most likely to be minimally impacted from influences of turbulence and motor, compressional, and frictional heating while still maintaining adequate airflow. When opting to use rotor wash as a means for sensor aspiration, the user must be cognizant of these potential sources of platform-induced heating when determining sensor location.

scholarly journals Considerations for temperature sensor placement on rotary-wing unmanned aircraft systems

2018 ◽  
Vol 11 (10) ◽  
pp. 5519-5530 ◽  
Author(s):  
Brian R. Greene ◽  
Antonio R. Segales ◽  
Sean Waugh ◽  
Simon Duthoit ◽  
Phillip B. Chilson
Keyword(s):  
Frictional Heating ◽  
Sensor Placement ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Heat Sources ◽  
Series Of Experiments ◽  
Aircraft System ◽  
Rotary Wing ◽  
Homogeneous Environment

Abstract. Integrating sensors with a rotary-wing unmanned aircraft system (rwUAS) can introduce several sources of biases and uncertainties if not properly accounted for. To maximize the potential for rwUAS to provide reliable observations, it is imperative to have an understanding of their strengths and limitations under varying environmental conditions. This study focuses on the quality of measurements relative to sensor locations on board rwUAS. Typically, thermistors require aspiration and proper siting free of heat sources to make representative measurements of the atmosphere. In an effort to characterize ideal locations for sensor placement, a series of experiments were conducted in the homogeneous environment of an indoor chamber with a pedestal-mounted rwUAS. A suite of thermistors along with a wind probe were mounted inside of a solar shield, which was affixed to a linear actuator arm. The actuator arm was configured such that the sensors within the solar shield would travel underneath the platform into and out of the propeller wash. The actuator arm was displaced horizontally underneath the platform while the motors were throttled to 50 %, yielding a time series of temperature and wind speed that could be compared to temperatures being collected in the ambient environment. Results indicate that temperatures may be biased in the order of 0.5–1.0 ∘C and vary appreciably without aspiration, sensors placed close to the tips of the rotors may experience biases due to frictional and compressional heating as a result of turbulent fluctuations, and sensors in proximity to motors may experience biases approaching 1 ∘C. From these trials, it has been determined that sensor placement underneath a propeller on an rwUAS a distance of one quarter the length of the propeller from the tip is most likely to be minimally impacted from influences of turbulence and motor, compressional, and frictional heating while still maintaining adequate airflow. When opting to use rotor wash as a means for sensor aspiration, the user must be cognizant of these potential sources of platform-induced heating when determining sensor location.

scholarly journals The Impact of Sensor Response and Airspeed on the Representation of the Convective Boundary Layer and Airmass Boundaries by Small Unmanned Aircraft Systems

2018 ◽  
Vol 35 (8) ◽  
pp. 1687-1699 ◽  
Author(s):  
Adam L. Houston ◽  
Jason M. Keeler
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Sensor Response ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Lapse Rate ◽  
Convective Boundary ◽  
Aircraft Systems ◽  
The Impact ◽  
Rotary Wing

AbstractThe objective of the research presented is to assess the impact of sensor response and aircraft airspeed on the accuracy of in situ observations collected by small unmanned aircraft systems profiling the convective boundary layer or transecting airmass boundaries. Estimates are made using simulated aircraft flown within large-eddy simulations. Both instantaneous errors (differences between observed temperature, which include the effects of sensor response and airspeed, and actual temperature) and errors in representation (differences between serial observations and representative snapshots of the atmospheric state) are considered. Synthetic data are retrieved assuming a well-aspirated first-order sensor mounted on rotary-wing aircraft operated as profilers in a simulated CBL and fixed-wing aircraft operated through transects across a simulated airmass boundary. Instantaneous errors are found to scale directly with sensor response time and airspeed for both CBL and airmass boundary experiments. Maximum errors tend to be larger for airmass boundary transects compared to the CBL profiles. Instantaneous errors for rotary-wing aircraft profiles in the CBL simulated for this work are attributable to the background lapse rate and not to turbulent temperature perturbations. For airmass boundary flights, representation accuracy is found to degrade with decreasing airspeed. This signal is most pronounced for flights that encounter the density current wake. When representation errors also include instantaneous errors resulting from sensor response, instantaneous errors are found to be dominant for flights that remain below the turbulent wake. However, for flights that encounter the wake, sensor response times generally need to exceed ~5 s before instantaneous errors become larger than errors in representation.

scholarly journals Integrating Unmanned Aircraft Systems to Measure Linear and Areal Features into Undergraduate Forestry Education

2018 ◽  
Vol 7 (4) ◽  
pp. 63 ◽  
Author(s):  
Reid Viegut ◽  
David L. Kulhavy ◽  
Daniel R Unger ◽  
I-Kuai Hung ◽  
Brian Humphreys
Keyword(s):  
Google Earth ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
P Value ◽  
Linear Measurements ◽  
Linear Feature ◽  
Aircraft Systems ◽  
Significant Difference ◽  
Forestry Education

The use of Unmanned Aircraft Systems (UAS) in undergraduate forestry education continues to expand and develop. Accuracy of data collection is an important aspect of preparation for “society-ready” foresters to meet the complex sustainable environment managing for ecological, social and economic interests.  Hands-on use of a DJI Phantom 4 Pro UAS by undergraduates to measure the length and area of 30 linear features and areal features on Earth’s surface were estimated.  These measurements were compared (measured within the ArcMap 10.5.2 interface) to hyperspectral Pictometry imagery measured on the web-based interface and the Google Earth Pro interface. Each remotely estimated measurement was verified with the actual ground measurements and the methods compared. An analysis of variance, conducted on the absolute length errors resulting in a p-value of 0.000057, concluded that the three length estimating techniques were statistically different at a 95% confidence interval. A Tukey pair-wise test found that the remotely sensed DJI Phantom 4 Pro data was statistically less accurate than the Pictometry and Google Earth Pro data, while both of which were found to be not different statistically in terms of accuracy. The areal feature area measurements were not normally distributed and therefore tested for equal medians using a Kruskal-Wallis test. The test found that there was no significant difference between sample medians, indicating that all three methods of estimating area are statistically equal in accuracy. The results indicate that Pictometry and Google Earth Pro could both be used to accurately estimate linear feature lengths remotely in lieu of in situ linear measurements while all three remote sensing techniques can be used to accurately estimate areal feature areas remotely in lieu of in situ areal measurements.

scholarly journals Investigation of Rotor–Airframe Interaction Noise Associated with Small-Scale Rotary-Wing Unmanned Aircraft Systems

2020 ◽  
Vol 65 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Nikolas S. Zawodny ◽  
Douglas D. Boyd
Keyword(s):  
Rotor Blade ◽  
Unmanned Aircraft ◽  
Tip Clearance ◽  
Unmanned Aircraft Systems ◽  
Small Scale ◽  
Acoustic Measurements ◽  
Aircraft Systems ◽  
Brushless Motor ◽  
Close Proximity ◽  
Rotary Wing

In this study, acoustic measurements of a hover condition are taken on isolated rotor–airframe configurations representative of small-scale, rotary-wing unmanned aircraft systems (UAS). Each rotor–airframe configuration consists of two fixed-pitch blades powered by a brushless motor, with a simplified airframe geometry intended to represent a generic multicopter arm. In addition to acoustic measurements, computational fluid dynamics–based aeroacoustic predictions are implemented on a subset of the experimentally tested rotor–airframe configurations in an effort to better understand the noise content of the rotor–airframe systems. Favorable agreements are obtained between acoustic measurements and predictions, based on both time- and frequency-domain postprocessing techniques. Results indicate that close proximity of airframe surfaces results in the generation of considerable tonal acoustic content in the form of harmonics of the rotor blade passage frequency (BPF). Analysis of the acoustic prediction data shows that the presence of the airframe surfaces can generate noise levels either comparable to or greater than the rotor blade surfaces under certain rotor tip clearance conditions. Analysis of the on-surface Ffowcs Williams and Hawkings source terms provides insight as to the predicted physical noise-generating mechanisms on the rotor and airframe surfaces.

scholarly journals Development and Deployment of Air-Launched Drifters from Small UAS

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2149 ◽  
Author(s):  
Sara Swenson ◽  
Brian Argrow ◽  
Eric Frew ◽  
Steve Borenstein ◽  
Jason Keeler
Keyword(s):  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
High Fidelity ◽  
Atmospheric Research ◽  
Aircraft Systems ◽  
Lagrangian Drifters ◽  
Industry Standards ◽  
Remotely Piloted Aircraft ◽  
Gust Front

Supercell thunderstorms can form extremely dangerous and destructive tornadoes. While high fidelity supercell simulations have increased the understanding of supercell mechanics to help determine how and when tornadoes form, there is a lack of targeted, in situ measurements taken aboveground in supercells to validate these simulations. Pseudo-Lagrangian drifters (PLDs) are atmospheric probes that can be used to attain thermodynamic measurements in areas that are difficult or dangerous to access, such as from within supercells. Of particular interest in understanding tornadogenesis is the rear-flank downdraft (RFD). However, strong outflow winds behind the rear-flank gust front (RFGF) make the RFD particularly difficult to access with balloon-borne sensors launched from the ground. A specific type of PLD, an air-launched drifter (ALD) that is released from unmanned aircraft systems (UAS), can be used to access RFD inflows, present at higher altitudes. Results from initial tests of ALDs are shown, along with results from a ground-released PLD test during a supercell intercept in the Oklahoma Panhandle on 12 June 2018. In characterization tests performed at the 2018 International Society for Atmospheric Research using Remotely piloted Aircraft (ISARRA) flight week, it was found that the ALD sensor system performs reasonably well against industry standards. However, improvements will be made to increase the aspiration of the sensor.

METHODOLOGICAL FOUNDATIONS OF COMPETITION ON THE SKILL OF USAGE OF UNMANNED AIRCRAFT SYSTEMS IN EMERCOM OF RUSSIA

2021 ◽  
pp. 42-51
Author(s):  
Алексей Анатольевич Лопухов ◽  
Екатерина Александровна Вахлина ◽  
Юрий Николаевич Осипов ◽  
Владимир Иванович Ершов
Keyword(s):  
Creative Thinking ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
The Other ◽  
Educational Institutions ◽  
Professional Skill ◽  
Aircraft Systems ◽  
Other Hand ◽  
The One

В статье рассмотрены вопросы, касающиеся организации проведения соревнований по мастерству применения беспилотных авиационных систем в МЧС России. Актуальность материала статьи обусловлена, с одной стороны, распространением в большинстве организаций конкурсов профессионального мастерства, помогающих повысить качество подготовки и креативного мышления специалистов, а с другой - недостаточным опытом их проведения в МЧС России. По результатам анализа материалов публикаций о рассматриваемой деятельности в учебных заведениях и трудовых коллективах страны авторами выработаны и представлены в статье рекомендации по организации интересуемых соревнований. The article discusses the issues related to performance of competitions on the skill of usage of unmanned aircraft systems in EMERCOM of Russia. The relevance of the article is, on the one hand, due to the spread of professional skill contests in most organizations that help to improve the quality of training and creative thinking of specialists, and on the other hand, due to insufficient experience of its conduction in EMERCOM of Russia. The authors have developed and presented the recommendations on the organization of interested competitions based on the results of analysis of the publication materials concerning discussed activities in educational institutions and labor collectives of our country.

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