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Jamey Jacob

Oklahoma State University, Aerospace, Faculty Member

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Jamey Jacob is the Director of the OSU Unmanned Systems Research Institute and John Hendrix Chair and Professor of Aerospace Engineering in the School of Mechanical and Aerospace Engineering at Oklahoma State University. He is currently lead on the NASA University Leadership Initiative program WINDMAP to develop aviation weather solutions for advanced aerial mobility applications, including drones and urban air taxis. He also leads the Counter-UAS Center of Excellence. He received his B.S. in Aerospace Engineering from the University of Oklahoma in 1990 and his M.S and Ph.D. in Mechanical Engineering from the University of California at Berkeley in 1992 and 1995, respectively.

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Papers by Jamey Jacob

Connecting implicit and explicit large eddy simulations of two-dimensional turbulence through machine learning

arXiv (Cornell University), Jan 27, 2019

In this article, we utilize machine learning to dynamically determine if a point on the computati... more In this article, we utilize machine learning to dynamically determine if a point on the computational grid requires implicit numerical dissipation for large eddy simulation (LES). The decision making process is learnt through a priori training on quantities derived from direct numerical simulation (DNS) data. In particular, we compute eddy-viscosities obtained through the coarse graining of DNS quantities and utilize their distribution to categorize areas that require dissipation. If our learning determines that closure is necessary, an upwinded scheme is utilized for computing the non-linear Jacobian. In contrast, if it is determined that closure is unnecessary, a symmetric and second-order accurate energy and enstrophy preserving Arakawa scheme is utilized instead. This results in a closure framework that precludes the specification of any model-form for the small scale contributions of turbulence but deploys an appropriate numerical dissipation from explicit closure driven hypotheses. This methodology is deployed for the Kraichnan turbulence test-case and assessed through various statistical quantities such as angle-averaged kinetic energy spectra and vorticity structure functions. Our framework thus establishes a direct link between the use of explicit LES ideologies for closure and numerical scheme-based modeling of turbulence leading to improved statistical fidelity of a posteriori simulations.

Application of UAS-Based Remote Sensing in Estimating Winter Wheat Phenotypic Traits and Yield During the Growing Season

Pfg – Journal Of Photogrammetry, Remote Sensing And Geoinformation Science, Jan 20, 2023

Phenotyping approaches have been considered as a vital component in crop breeding programs to imp... more Phenotyping approaches have been considered as a vital component in crop breeding programs to improve crops and develop new high-yielding cultivars. However, traditional field-based monitoring methods are expensive, invasive, and time-intensive. Moreover, data collected using satellite and airborne platforms are either costly or limited by their spatial and temporal resolution. Here, we investigated whether low-cost unmanned/unoccupied aerial systems (UASs) data can be used to estimate winter wheat (Triticum aestivum L.) nitrogen (N) content, structural traits including plant height, fresh and dry biomass, and leaf area index (LAI) as well as yield during different winter wheat growing stages. To achieve this objective, UAS-based red-green-blue (RGB) and multispectral data were collected from winter wheat experimental plots during the winter wheat growing season. In addition, for each UAS flight mission, winter wheat traits and total yield (only at harvest) were measured through field sampling for model development and validation. We then used a set of vegetation indices (VIs), machine learning algorithms (MLAs), and structure-from-motion (SfM) to estimate winter wheat traits and yield. We found that using linear regression and MLAs, instead of using VIs, improved the capability of UAS-derived data in estimating winter wheat traits and yield. Further, considering the costly and time-intensive process of collecting in-situ data for developing MLAs, using SfM-derived elevation models and red-edge-based VIs, such as CIre and NDRE, are reliable alternatives for estimating key winter wheat traits. Our findings can potentially aid breeders through providing rapid and non-destructive proxies of winter wheat phenotypic traits. Unmanned/unoccupied aerial system (UAS) • Phenotyping • Vegetation indices (VIs) • Machine learning algorithm (MLA) • Structure-from-motion (SfM) • Winter wheat * Kianoosh Hassani

Wind Speed Statistics from a Small UAS and Its Sensitivity to Sensor Location

Atmosphere, Mar 9, 2022

With the increase in the use of small uncrewed aircraft systems (UAS) there is a growing need for... more With the increase in the use of small uncrewed aircraft systems (UAS) there is a growing need for real-time weather forecasting to improve the safety of low-altitude aircraft operations. This will require integration of measurements with autonomous systems since current available sampling lack sufficient resolution within the atmospheric boundary layer (ABL). Thus, the current work aims to assess the ability to measure wind speeds from a quad-copter UAS and compare the performance with that of a fixed mast. Two laboratory tests were initially performed to assess the spatial variation in the vertically induced flow from the rotors. The horizontal distribution above the rotors was examined in a water tunnel at speeds and rotation rates to simulate nominally full throttle with a relative air speed of 0 or 8 m/s. These results showed that the sensor should be placed between rotor pairs. The vertical distribution was examined from a single rotor test in a large chamber, which suggested that at full throttle the sensor should be about 400 mm above the rotor plane. Field testing was then performed with the sensor positioned in between both pairs of rotors at 406, 508, and 610 mm above the rotor plane. The mean velocity over the given period was within 5.5% of the that measured from a fixed mast over the same period. The variation between the UAS and mast sensors were better correlated with the local mean shear than separation distance, which suggests height mismatch could be the source of error. The fluctuating velocity was quantified with the comparison of higher order statistics as well as the power spectral density, which the mast and UAS spectra were in good agreement regardless of the separation distance. This implies that for the current configuration a separation distance of 5.3 rotor diameters was sufficient to minimize the influence of the rotors.

Considerations for Atmospheric Measurements with Small Unmanned Aircraft Systems

Atmosphere, Jul 5, 2018

This paper discusses results of the CLOUD-MAP (Collaboration Leading Operational UAS Development ... more This paper discusses results of the CLOUD-MAP (Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics) project dedicated to developing, fielding, and evaluating integrated small unmanned aircraft systems (sUAS) for enhanced atmospheric physics measurements. The project team includes atmospheric scientists, meteorologists, engineers, computer scientists, geographers, and chemists necessary to evaluate the needs and develop the advanced sensing and imaging, robust autonomous navigation, enhanced data communication, and data management capabilities required to use sUAS in atmospheric physics. Annual integrated evaluation of the systems in coordinated field tests are being used to validate sensor performance while integrated into various sUAS platforms. This paper focuses on aspects related to atmospheric sampling of thermodynamic parameters with sUAS, specifically sensor integration and calibration/validation, particularly as it relates to boundary layer profiling. Validation of sensor output is performed by comparing measurements with known values, including instrumented towers, radiosondes, and other validated sUAS platforms. Experiments to determine the impact of sensor location and vehicle operation have been performed, with sensor aspiration a major factor. Measurements are robust provided that instrument packages are properly mounted in locations that provide adequate air flow and proper solar shielding.

Design and Development of a Tornado Intercept Unmanned Aerial Vehicle

AIAA Aviation 2019 Forum, Jun 15, 2019

Very little data surrounding tornadogenesis exists, and this is due in part to the lack of tools ... more Very little data surrounding tornadogenesis exists, and this is due in part to the lack of tools necessary to deliver weather-sensing instruments into the severe weather phenomenon. Though current UAS are able to accurately gather weather data, they typically cannot operate in high winds or in rain. To help bridge this data gap, a custom delta wing UAS was developed to withstand both of these shortcomings. The aircraft was outfitted with an autopilot, long range RC control, and FPV systems for control over long distances. Despite utilizing a new turbojet that generates 50% more thrust at the cost of a 50% increase to fuel consumption, custom fuel tanks were designed and fabricated double the flight time of the previous system. Considerations for preventing ingested water from damaging internal avionics are explored, as operation in rain is a requirement. Aircraft performance approximations were generated using both analytical approximations and flight test data from the autopilot's flight log. An approach to generating a longitudinal aerodynamic control model is explored to estimate performance in extreme winds (75+ mph), but ultimately fails due to lack of conventional horizontal tail and the coupling of pitch and yaw controls to the turbine's exhaust speed (controlled by throttle setting). A car-based launcher system was also created for utilization in the field, reducing the required personnel's experience to execute a mission effectively. Multiple aircraft, as well as a prototype of the TIA, has launched successfully multiple times from this system, even exhibiting full auto-launching functionality. The longest recorded flight was over a ground track of 22 miles with an average airspeed of 100 knots over 16 minutes, consuming 60% of the total fuel available. The top speed achieved by the aircraft was 160 mph at 90% throttle.

Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger

Bulletin of the American Physical Society, Nov 25, 2013

The American Physical Society Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger AK-SHAY KHAND... more The American Physical Society Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger AK-SHAY KHANDEKAR, JAMEY JACOB, Oklahoma State University -Merger of vortices is examined experimentally to compare the merger of slender parallel vortices generated either coincidentally or continuously. It is known that like-sign vortices rotate around a common center of circulation and merger between the vortices may occur under certain conditions. This merger is dependent on the strength of the vortex circulation, distance of separation between the centers of the two vortices, Re Γ , and vorticity distribution. Quasi-2D and 3D experimental data is examined and merger relations are derived. The former uses high aspect ratio rotating paddles in a tank and while the latter are from wing-tip vortices in a wind tunnel. The vortex merger tank generates slender co-rotating vortices and are examined using PIV, while in the wind tunnel two opposing wings are arranged at opposite angles of attack to generate a pair of vortices that merge downstream. A 5-hole probe is used to obtain 3D velocity vectors via wake survey, along with PIV. The procedure is performed in the wake at different distances to observe merger under different conditions. Temporally and spatially dependent relations in quasi-2D and 3D vortex merger are derived. Merger behavior is generally similar between the cases, but instabilities along quasi-2D vortices may affect

Airborne Measurement of Insolation Impact on the Atmospheric Surface Boundary Layer

Bulletin of the American Physical Society, Nov 20, 2017

MAP TEAM -Atmospheric surface boundary layer measurements of wind and thermodynamic parameters ar... more MAP TEAM -Atmospheric surface boundary layer measurements of wind and thermodynamic parameters are conducted during variable insolation conditions, including the 2017 eclipse, using an unmanned aircraft system. It is well known that the air temperatures can drop significantly during a total solar eclipse as has been previously observed. In past eclipses, these observations have primarily been made on the ground. We present results from airborne measurements of the near surface boundary layer using a small unmanned aircraft with high temporal resolution wind and thermodynamic observations. Questions that motivate the study include: How does the temperature within the lower atmospheric boundary vary during an eclipse? What impact does the immediate removal of radiative heating on the ground have on the lower ABL? Do local wind patterns change during an eclipse event and if so why? Will there be a manifestation of the nocturnal boundary layer wind maximum? Comparisons are made with the DOE ARM SGP site that experiences a lower but still significant insolation.

Bird Flight as a Model for a Course in Unsteady Aerodynamics

Bulletin of the American Physical Society, Nov 23, 2014

Bird Flight as a Model for a Course in Unsteady Aerodynamics JAMEY JACOB, JONATHAN MITCHELL, MICH... more Bird Flight as a Model for a Course in Unsteady Aerodynamics JAMEY JACOB, JONATHAN MITCHELL, MICHAEL PUOPOLO, Oklahoma State University -Traditional unsteady aerodynamics courses at the graduate level focus on theoretical formulations of oscillating airfoil behavior. Aerodynamics students with a vision for understanding bird-flight and small unmanned aircraft dynamics desire to move beyond traditional flow models towards new and creative ways of appreciating the motion of agile flight systems. High-speed videos are used to record kinematics of bird flight, particularly barred owls and red-shouldered hawks during perching maneuvers, and compared with model aircraft performing similar maneuvers. Development of a perching glider and associated control laws to model the dynamics are used as a class project. Observations are used to determine what different species and sizes of birds share in their methods to approach a perch under similar conditions. Using fundamental flight dynamics, simplified models capable of predicting position, attitude, and velocity of the flier are developed and compared with the observations. By comparing the measured data from the videos and predicted and measured motions from the glider models, it is hoped that the students gain a better understanding of the complexity of unsteady aerodynamics and aeronautics and an appreciation for the beauty of avian flight.

Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control

Bulletin of the American Physical Society, Nov 25, 2013

Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control LIBIN DANIEL, J... more Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control LIBIN DANIEL, JAMEY JACOB, Oklahoma State University -This presentation discusses results from an experimental study of the power profile airfoil at low Reynolds number. The power profile airfoil was developed by AMO Smith and consists of a blunt trailing edge shape with two wall jets near the trailing edge. The replacement of streamlining with properly designed blowing is used to prevent flow separation and additionally offers potential applications as a powered high-lift system, propulsive system, or low inertia control device. The 2D wind-tunnel model consists of the 22.5% thick power profile airfoil equipped with a movable trailing edge plug to direct flow along the trailing edge streamline. Compressed air was passed into the model via a plenum with flow conditioning devices to create pressure backdrop to allow uniform blowing at the trailing edge. The effects of varying jet momentum coefficient and trailing edge positioning on the aerodynamic characteristics are observed with both wake surveys and PIV. The impact of plasma synthetic jet actuators (PSJA) placed along the trailing edge of the power profile airfoil is also discussed. PSJA operation is compared to the baseline power profile airfoil both alone and working with the blowing to provide additional control authority.

Perching Dynamics and Development of a Simple Model

Bulletin of the American Physical Society, Nov 25, 2013

Wing Warping and Its Impact on Aerodynamic Efficiency

Bulletin of the American Physical Society, Nov 20, 2007

Wing Warping and Its Impact on Aerodynamic Efficiency BEN LOH, JAMEY JACOB, Oklahoma State Univer... more Wing Warping and Its Impact on Aerodynamic Efficiency BEN LOH, JAMEY JACOB, Oklahoma State University -Inflatable wings have been demonstrated in many applications such as UAVs, airships, and missile stabilization surfaces. A major concern presented by the use of an inflatable wing has been the lack of traditional roll control surfaces. This leaves the designer with several options in order to have control about the roll axis. Since inflatable wings have a semiflexible structure, wing warping is the obvious solution to this problem. The current method is to attach servos and control linkages to external surface of the wing that results in variation of profile chamber and angle of attack from leading edge or trailing edge deflection. Designs using internal muscles will also be discussed. This creates a lift differential between the half-spans, resulting in a roll moment. The trailing edge on the other half-span can also be deflected in the opposite direction to increase the roll moment as well as to reduce roll-yaw coupling. Comparisons show that higher L/D ratios are possible than using traditional control surfaces. An additional benefit is the ability to perform symmetric warping to achieve optimum aerodynamic performance. Via warping alone, an arbitrary span can be warped such that it has the same aerodynamic characteristics as an elliptical planform. Comparisons between lifting line theory and test results will be presented.

Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings

Bulletin of the American Physical Society, Nov 21, 2005

Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings ANDREW SIMPSON, SUZAN... more Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings ANDREW SIMPSON, SUZANNE SMITH, JAMEY JACOB, University of Kentucky -The research presents work on aerodynamic control by warping inflatable wings. Inflatable wings are deformable by their nature. Mechanical manipulation of the wing's shape has been demonstrated to alter the performance and control the vehicle in flight by deforming the trailing edge of the wing near the wing tip. Predicting and correlating the forces required in deforming the wings to a particular shape and the deformation generated for a given internal pressure were conducted through the use of photogrammetry. This research focuses on optimizing the roll moments and aerodynamic performance of the vehicle, given the current level of wing warping ability. Predictions from lifting line theory applied to wing shape changes are presented. Comparisons from the experimental results are made with lifting line analysis for wings with arbitrary twist and the solutions are used to determine rolling moment and optimum L/D. Results from flight tests will also be presented.

Thrust Vectoring Flow Control Using Plasma Actuators

Bulletin of the American Physical Society, Nov 20, 2007

Thrust Vectoring Flow Control Using Plasma Actuators JAMEY JACOB, MICHAEL BOLITHO, Oklahoma State... more Thrust Vectoring Flow Control Using Plasma Actuators JAMEY JACOB, MICHAEL BOLITHO, Oklahoma State University -Thrust vectoring flow control is demonstrated using plasma synthetic jet actuators (PSJA). The PSJA is a geometric variant of a plasma actuator, consisting of a symmetric electrode array that results in a circular region of dielectric barrier discharge plasma. Quiescent flow PIV measurements of the PSJA reveal that the flowfield on actuation resembles that of a zero-mass flux or synthetic jet that is useful for flow control, particularly separation reduction. Like synthetic jets, unsteady pulsed actuator operation results in formation of multiple vortex rings. The output jet momentum is found to be affected by the power input, actuator dimension and pulsing frequency. While increasing the input power increases the maximum jet velocity, an optimum range of pulsing frequencies and actuator dimensions are observed to exist in order to maximize jet momentum. By asymmetrically varying the plasma input parameters, such as frequency, amplitude and duty cycle, it is possible to control the jet angle. Vectoring using high frequency pusling akin to synthetic jets is more effective than vectoring by modifying steady control inputs and differences in control effectiveness are due primarily to the time scales associated with the vortex formation.

Characteristics of Plasma Synthetic Jet Actuators in Crossflow

Bulletin of the American Physical Society, Nov 19, 2006

Characteristics of Plasma Synthetic Jet Actuators in Crossflow ARVIND SANTHANAKRISHNAN, Universit... more Characteristics of Plasma Synthetic Jet Actuators in Crossflow ARVIND SANTHANAKRISHNAN, University of Kentucky, JAMEY JACOB, Oklahoma State University -The plasma synthetic jet actuator (PSJA) consists of two annular electrodes separated by dielectric material that results in a circular region of dielectric barrier discharge plasma. In quiescent conditions, this plasma ring produces a synthetic jet which can be used for active flow control applications. Unsteady pulsing of the actuator results in the formation of multiple primary and secondary vortex rings, the latter remaining fixed or trapped in space. The jet is observed to be formed by the advection and interaction of the primary vortices, resembling a conventional synthetic jet. This presentation examines the operation of the PSJA in a crossflow at three different jet to freestream velocity ratios. PIV measurements in the streamwise and cross-stream planes are used to illustrate the three dimensionality of the jet and associated vortical structures. The strength of the vortex ring is found to vary along its circumference due to interaction with the freestream. The boundary layer characteristics obtained from these experiments suggest that the mechanism of the PSJA in crossflow is similar to an active boundary layer trip. Both the penetration of the jet and effectiveness of the trip action are found to decrease with increase in freestream velocity. The effects of unsteady pulsing and increasing input power on actuator created crossflow vortices will also be presented.

Characterization of Zero Mass Flux Flow Control of Airfoil Separation at Low Re

Bulletin of the American Physical Society, Nov 20, 2005

Corotating Vortex Formation, Merger, and Modification

Bulletin of the American Physical Society, Nov 21, 2005

Corotating Vortex Formation, Merger, and Modification JAMEY JACOB, University of Kentucky -Experi... more Corotating Vortex Formation, Merger, and Modification JAMEY JACOB, University of Kentucky -Experimental results from a combined wind tunnel and tow tank study on the evolution, interaction, and merger of two corotating trailing vortices are presented. In the current study, NACA 0012 airfoils positioned at positive and negative angles of attack are used to generate a corotating vortex pair. Measurements with a seven-hole probe are used to extract 3-D velocity and pressure fields in the tunnel while PIV is used in the tow tank to measure 2-D velocity fields in the vortex wake. The semi-span length is varied in the experiments to investigate the effects of initial separation on vortex formation and merger. Experimental information of the vortex motion is compared with theoretical predictions. Comparison shows that at larger initial separations, the motion of the vortex pair is well estimated from the 2-D analysis, while at smaller separations, the motion of the vortex pair cannot be well predicted from the results of the line vortex assumption. Effects in forcing vortex breakup using a virtual winglet from a plasma actuator are presented. At sufficient power inputs, the virtual winglet can substantially modify the vortex circulation magnitude and distribution. Comparisons of information confidence and data quality are made between the two measurement techniques and facilities. Finally, comparisons of differences in the vortex roll-up and evolution due to initial separation changes are discussed and contrasted to that of a single tip vortex and corotating vortex pair on a wing with flap.

Evaluation of Cylindrical Asymmetric Surface Dielectric Barrier Discharge Actuators for Surface Decontamination and Mixing

Plasma, Nov 25, 2021

Surface dielectric barrier discharge (SDBD) was used to evaluate cylindrical plasma actuators for... more Surface dielectric barrier discharge (SDBD) was used to evaluate cylindrical plasma actuators for inactivation of Salmonella enterica. A cylindrical SDBD configuration was evaluated to determine if the inherent induced body force could be leveraged to impel plasma species, such as reactive oxygen and nitrogen species (RONS), as an apparatus to sterilize surfaces. The cylindrical structure is evaluated in this study to observe whether an increase in mixing is possible to efficiently distribute the plasma species, thereby improving bacterial inactivation efficiency. The increase in induced airflow of SDBD actuators with increased numbers of electrodes correlates with increased bacterial inactivation. These results suggest that improving the particle velocity, airflow mixing tendencies, and plasma volume for the same power inputs (same net power to the actuators) results in increased surface decontamination efficiency.

Real-Time Traffic End-of-Queue Detection and Tracking in UAV Video

arXiv (Cornell University), Jan 9, 2023

Highway work zones are susceptible to undue accumulation of motorized vehicles which calls for dy... more Highway work zones are susceptible to undue accumulation of motorized vehicles which calls for dynamic work zone warning signs to prevent accidents. The work zone signs are placed according to the location of the end-of-queue of vehicles which usually changes rapidly. The detection of moving objects in video captured by Unmanned Aerial Vehicles (UAV) has been extensively researched so far, and is used in a wide array of applications including traffic monitoring. Unlike the fixed traffic cameras, UAVs can be used to

Soil Moisture Monitoring Through UAS-Assisted Internet of Things LoRaWAN Wireless Underground Sensors

IEEE Access

With growing usage and demand for the global freshwater supply, there is an increasing need for t... more With growing usage and demand for the global freshwater supply, there is an increasing need for technologies that facilitate water conservation and environmental stewardship in irrigated agriculture. Toward this end, recent demonstrations of Internet of Things (IoT) sensors have revealed the value of wireless soil moisture content sensors. However, existing wireless solutions often employ above-ground wireless communication modules that physically interfere with routine farming operations. Underground wireless network solutions are severely challenged by the large radio-frequency (RF) propagation loss through soil. This paper presents a method that overcomes both problems by employing completely buried underground IoT sensors and communication modules with UAS (uncrewed aircraft system) mounted LoRaWAN gateways. The UAS mounted LoRaWAN gateway eliminates the need for any in-field base stations and also allows the LoRa enabled sensors to transmit data over short distances with very low energy. Field tests were carried out using this approach to serve as a proof of concept. The RSSI (received signal strength indicator) demonstrates that the proposed solution has good communication link margin and a significantly larger communication range than is necessary for reliable operation. Moreover, this solution is easy to build, scalable, cost-effective, and can be implemented in a highly power efficient fashion. 15 16 for monitoring soil moisture is preferable to avoid the cost and 38 complexity of laying and maintaining long lengths of cable. 39 In the wireless scheme, multiple sensors can be deployed in a 40 field to set up a wireless sensor network that can convey soil 41 moisture data from various parts of the field to the network 42 server. Several wireless technologies have been demonstrated 43 in this regard for precision agriculture, including GPRS (Gen-44 eral Packet Radio Service), GSM (Global System for Mobile 45 Communication), Wi-Fi, Bluetooth, and Zigbee [7]. In a 46 similar application, forest fire monitoring systems based on 47 Zigbee wireless sensors have also been demonstrated [8]. 48 The research challenges of wireless underground sensor 49 networks have been reviewed in [9]. If all sensor nodes and 50 communication modules can be placed completely under-51 ground, then devices can avoid interfering with farm machin-52 ery, a significant attraction. The main challenge of this 53 scheme is the high RF (radio frequency) path loss, which 54 causes low data rate for a given power, or high power con-55 sumption for a given data rate compared to above-ground 56 communication [9]. Data cannot be transported over long 57 distance in an underground sensor network without excessive 58 power use, so it must be re-routed relatively quickly to an 59 above-ground stationary or mobile base stations or gateways 60 [9]. This challenge is compensated by setting up a dense array 61 of above-ground base stations, which is neither cost-effective 62 nor practical. As a less traditional wireless solution, magnetic 63 induction was also investigated for underground communica-64 tion [10]. This technique leverages the lower material losses 65 of non-propagating magnetic fields for communication, but 66 also suffers a very short range due to the more rapid roll-off 67 of near-field power density. Underground magnetic induction 68 waveguide systems were subsequently investigated, which 69 proved that a large range can be achieved by employing a 70 large number of relay coils in short intervals between the 71 transmitter and receiver [11]. While feasible, this dramati-72 cally increases the complexity and cost of this solution. 73 More possible agricultural solutions have emerged under 74 the umbrella of the Internet of Things (IoT) -a vast network 75 of relatively simple devices such as sensors and cameras, 76 connected to the internet via (predominantly) wireless com-77 munication networks [12]. For example, [13] employed an 78 IoT-based wireless sensor network to develop a Greenhouse 79 Irrigation Management System to monitor various agricul-80 tural parameters including soil moisture. It is significant to 81 this work that a variant of IoT called the Internet of Under-82 ground Things (IoUT) has developed with applications in 83 agriculture wherein interconnected things are partially or 84 completely placed underground [14]. 85 LoRa is a wireless radio technology and LoRaWAN is a 86 wide area network protocol that incorporates the LoRa tech-87 nology [15]. In IoT applications, the LoRaWAN (Low Range 88 Wide Area Network), or just LoRa, protocol has emerged as 89 a very promising technology since it allows long range, low 90 data rate wireless communication utilizing very low power 91 LoRa enabled sensors [16]. After analyzing many different 92 technologies, some researchers have concluded that for smart 93

Evaluation of Onboard Detect-and-Avoid System for sUAS BVLOS Operations

International Journal of Aviation, Aeronautics, and Aerospace

Small Unmanned Aircraft Systems (sUAS) have expanded rapidly in the past few years due to their a... more Small Unmanned Aircraft Systems (sUAS) have expanded rapidly in the past few years due to their ability to greatly expand commercial and civilian aviation capabilities. As growth continues, many sUAS operations will require coexistence with other aircraft operating within the National Airspace System (NAS). For now, sUAS and other Advanced Air Mobility (AAM) solutions currently have restricted access to the NAS for their inability to detect-and-avoid other air traffic. Safety is the primary concern and the critical challenge to overcome among many regulatory and technological (sensing, command, control, and communication) hurdles prior to full AAM integration into the NAS. The Federal Aviation Administration (FAA), the United States national aviation authority, calls for a target level of safety equivalent to the manned aircraft see-and-avoid requirement (FAA, 2021). Unmanned Traffic Management (UTM) and Detect-And-Avoid (DAA) are two major obstacles in incorporating sUAS into NAS. A successful UTM strategy will keep sUAS traffic secure and effective. DAA is a key component to a successful UTM system, which can be used by sUAS to track and avoid obstacles, other aircraft, and each other. For sUAS to provide the essential target level of safety, DAA systems will be required to be robust and reliable. Detection systems and associated trackers, collision detection, risk assessment, collision avoidance, and self-separation algorithms are typically included in a complete working DAA system. Despite their limited capabilities, vision-based DAA systems are becoming more common due to their light weight and low cost. In addition, they provide more information about the environment than other available sensors, making them ideal for sUAS with limited payload power. Over the years the need and use of sUAS has expanded into avenues that have changed the way corporate, military, commercial sectors are able to do business. This includes operating sUAS in locations that are hard for humans to reach or requires extensive equipment investment to do the job. To operate in the NAS, federal restrictions require sUAS to perform similarly to manned aircraft. For unmanned aircraft to maintain separation in congested airspace, this presents the difficult issue of not having the human pilot as the last line of defense. Therefore, DAA systems must achieve a level of safety that is equivalent to manned pilots or better, while balancing size, weight, and power constraints to maintain economic viability. This research is the 6th installment to be completed and published by the core research team. Previous studies focused on detecting and assessing the collision potential of manned aircraft and sUAS by Visual Observers

Connecting implicit and explicit large eddy simulations of two-dimensional turbulence through machine learning

arXiv (Cornell University), Jan 27, 2019

In this article, we utilize machine learning to dynamically determine if a point on the computati... more In this article, we utilize machine learning to dynamically determine if a point on the computational grid requires implicit numerical dissipation for large eddy simulation (LES). The decision making process is learnt through a priori training on quantities derived from direct numerical simulation (DNS) data. In particular, we compute eddy-viscosities obtained through the coarse graining of DNS quantities and utilize their distribution to categorize areas that require dissipation. If our learning determines that closure is necessary, an upwinded scheme is utilized for computing the non-linear Jacobian. In contrast, if it is determined that closure is unnecessary, a symmetric and second-order accurate energy and enstrophy preserving Arakawa scheme is utilized instead. This results in a closure framework that precludes the specification of any model-form for the small scale contributions of turbulence but deploys an appropriate numerical dissipation from explicit closure driven hypotheses. This methodology is deployed for the Kraichnan turbulence test-case and assessed through various statistical quantities such as angle-averaged kinetic energy spectra and vorticity structure functions. Our framework thus establishes a direct link between the use of explicit LES ideologies for closure and numerical scheme-based modeling of turbulence leading to improved statistical fidelity of a posteriori simulations.

Application of UAS-Based Remote Sensing in Estimating Winter Wheat Phenotypic Traits and Yield During the Growing Season

Pfg – Journal Of Photogrammetry, Remote Sensing And Geoinformation Science, Jan 20, 2023

Phenotyping approaches have been considered as a vital component in crop breeding programs to imp... more Phenotyping approaches have been considered as a vital component in crop breeding programs to improve crops and develop new high-yielding cultivars. However, traditional field-based monitoring methods are expensive, invasive, and time-intensive. Moreover, data collected using satellite and airborne platforms are either costly or limited by their spatial and temporal resolution. Here, we investigated whether low-cost unmanned/unoccupied aerial systems (UASs) data can be used to estimate winter wheat (Triticum aestivum L.) nitrogen (N) content, structural traits including plant height, fresh and dry biomass, and leaf area index (LAI) as well as yield during different winter wheat growing stages. To achieve this objective, UAS-based red-green-blue (RGB) and multispectral data were collected from winter wheat experimental plots during the winter wheat growing season. In addition, for each UAS flight mission, winter wheat traits and total yield (only at harvest) were measured through field sampling for model development and validation. We then used a set of vegetation indices (VIs), machine learning algorithms (MLAs), and structure-from-motion (SfM) to estimate winter wheat traits and yield. We found that using linear regression and MLAs, instead of using VIs, improved the capability of UAS-derived data in estimating winter wheat traits and yield. Further, considering the costly and time-intensive process of collecting in-situ data for developing MLAs, using SfM-derived elevation models and red-edge-based VIs, such as CIre and NDRE, are reliable alternatives for estimating key winter wheat traits. Our findings can potentially aid breeders through providing rapid and non-destructive proxies of winter wheat phenotypic traits. Unmanned/unoccupied aerial system (UAS) • Phenotyping • Vegetation indices (VIs) • Machine learning algorithm (MLA) • Structure-from-motion (SfM) • Winter wheat * Kianoosh Hassani

Wind Speed Statistics from a Small UAS and Its Sensitivity to Sensor Location

Atmosphere, Mar 9, 2022

With the increase in the use of small uncrewed aircraft systems (UAS) there is a growing need for... more With the increase in the use of small uncrewed aircraft systems (UAS) there is a growing need for real-time weather forecasting to improve the safety of low-altitude aircraft operations. This will require integration of measurements with autonomous systems since current available sampling lack sufficient resolution within the atmospheric boundary layer (ABL). Thus, the current work aims to assess the ability to measure wind speeds from a quad-copter UAS and compare the performance with that of a fixed mast. Two laboratory tests were initially performed to assess the spatial variation in the vertically induced flow from the rotors. The horizontal distribution above the rotors was examined in a water tunnel at speeds and rotation rates to simulate nominally full throttle with a relative air speed of 0 or 8 m/s. These results showed that the sensor should be placed between rotor pairs. The vertical distribution was examined from a single rotor test in a large chamber, which suggested that at full throttle the sensor should be about 400 mm above the rotor plane. Field testing was then performed with the sensor positioned in between both pairs of rotors at 406, 508, and 610 mm above the rotor plane. The mean velocity over the given period was within 5.5% of the that measured from a fixed mast over the same period. The variation between the UAS and mast sensors were better correlated with the local mean shear than separation distance, which suggests height mismatch could be the source of error. The fluctuating velocity was quantified with the comparison of higher order statistics as well as the power spectral density, which the mast and UAS spectra were in good agreement regardless of the separation distance. This implies that for the current configuration a separation distance of 5.3 rotor diameters was sufficient to minimize the influence of the rotors.

Considerations for Atmospheric Measurements with Small Unmanned Aircraft Systems

Atmosphere, Jul 5, 2018

This paper discusses results of the CLOUD-MAP (Collaboration Leading Operational UAS Development ... more This paper discusses results of the CLOUD-MAP (Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics) project dedicated to developing, fielding, and evaluating integrated small unmanned aircraft systems (sUAS) for enhanced atmospheric physics measurements. The project team includes atmospheric scientists, meteorologists, engineers, computer scientists, geographers, and chemists necessary to evaluate the needs and develop the advanced sensing and imaging, robust autonomous navigation, enhanced data communication, and data management capabilities required to use sUAS in atmospheric physics. Annual integrated evaluation of the systems in coordinated field tests are being used to validate sensor performance while integrated into various sUAS platforms. This paper focuses on aspects related to atmospheric sampling of thermodynamic parameters with sUAS, specifically sensor integration and calibration/validation, particularly as it relates to boundary layer profiling. Validation of sensor output is performed by comparing measurements with known values, including instrumented towers, radiosondes, and other validated sUAS platforms. Experiments to determine the impact of sensor location and vehicle operation have been performed, with sensor aspiration a major factor. Measurements are robust provided that instrument packages are properly mounted in locations that provide adequate air flow and proper solar shielding.

Design and Development of a Tornado Intercept Unmanned Aerial Vehicle

AIAA Aviation 2019 Forum, Jun 15, 2019

Very little data surrounding tornadogenesis exists, and this is due in part to the lack of tools ... more Very little data surrounding tornadogenesis exists, and this is due in part to the lack of tools necessary to deliver weather-sensing instruments into the severe weather phenomenon. Though current UAS are able to accurately gather weather data, they typically cannot operate in high winds or in rain. To help bridge this data gap, a custom delta wing UAS was developed to withstand both of these shortcomings. The aircraft was outfitted with an autopilot, long range RC control, and FPV systems for control over long distances. Despite utilizing a new turbojet that generates 50% more thrust at the cost of a 50% increase to fuel consumption, custom fuel tanks were designed and fabricated double the flight time of the previous system. Considerations for preventing ingested water from damaging internal avionics are explored, as operation in rain is a requirement. Aircraft performance approximations were generated using both analytical approximations and flight test data from the autopilot's flight log. An approach to generating a longitudinal aerodynamic control model is explored to estimate performance in extreme winds (75+ mph), but ultimately fails due to lack of conventional horizontal tail and the coupling of pitch and yaw controls to the turbine's exhaust speed (controlled by throttle setting). A car-based launcher system was also created for utilization in the field, reducing the required personnel's experience to execute a mission effectively. Multiple aircraft, as well as a prototype of the TIA, has launched successfully multiple times from this system, even exhibiting full auto-launching functionality. The longest recorded flight was over a ground track of 22 miles with an average airspeed of 100 knots over 16 minutes, consuming 60% of the total fuel available. The top speed achieved by the aircraft was 160 mph at 90% throttle.

Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger

Bulletin of the American Physical Society, Nov 25, 2013

The American Physical Society Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger AK-SHAY KHAND... more The American Physical Society Dynamics of Quasi 2D and 3D Co-rotating Vortex Merger AK-SHAY KHANDEKAR, JAMEY JACOB, Oklahoma State University -Merger of vortices is examined experimentally to compare the merger of slender parallel vortices generated either coincidentally or continuously. It is known that like-sign vortices rotate around a common center of circulation and merger between the vortices may occur under certain conditions. This merger is dependent on the strength of the vortex circulation, distance of separation between the centers of the two vortices, Re Γ , and vorticity distribution. Quasi-2D and 3D experimental data is examined and merger relations are derived. The former uses high aspect ratio rotating paddles in a tank and while the latter are from wing-tip vortices in a wind tunnel. The vortex merger tank generates slender co-rotating vortices and are examined using PIV, while in the wind tunnel two opposing wings are arranged at opposite angles of attack to generate a pair of vortices that merge downstream. A 5-hole probe is used to obtain 3D velocity vectors via wake survey, along with PIV. The procedure is performed in the wake at different distances to observe merger under different conditions. Temporally and spatially dependent relations in quasi-2D and 3D vortex merger are derived. Merger behavior is generally similar between the cases, but instabilities along quasi-2D vortices may affect

Airborne Measurement of Insolation Impact on the Atmospheric Surface Boundary Layer

Bulletin of the American Physical Society, Nov 20, 2017

MAP TEAM -Atmospheric surface boundary layer measurements of wind and thermodynamic parameters ar... more MAP TEAM -Atmospheric surface boundary layer measurements of wind and thermodynamic parameters are conducted during variable insolation conditions, including the 2017 eclipse, using an unmanned aircraft system. It is well known that the air temperatures can drop significantly during a total solar eclipse as has been previously observed. In past eclipses, these observations have primarily been made on the ground. We present results from airborne measurements of the near surface boundary layer using a small unmanned aircraft with high temporal resolution wind and thermodynamic observations. Questions that motivate the study include: How does the temperature within the lower atmospheric boundary vary during an eclipse? What impact does the immediate removal of radiative heating on the ground have on the lower ABL? Do local wind patterns change during an eclipse event and if so why? Will there be a manifestation of the nocturnal boundary layer wind maximum? Comparisons are made with the DOE ARM SGP site that experiences a lower but still significant insolation.

Bird Flight as a Model for a Course in Unsteady Aerodynamics

Bulletin of the American Physical Society, Nov 23, 2014

Bird Flight as a Model for a Course in Unsteady Aerodynamics JAMEY JACOB, JONATHAN MITCHELL, MICH... more Bird Flight as a Model for a Course in Unsteady Aerodynamics JAMEY JACOB, JONATHAN MITCHELL, MICHAEL PUOPOLO, Oklahoma State University -Traditional unsteady aerodynamics courses at the graduate level focus on theoretical formulations of oscillating airfoil behavior. Aerodynamics students with a vision for understanding bird-flight and small unmanned aircraft dynamics desire to move beyond traditional flow models towards new and creative ways of appreciating the motion of agile flight systems. High-speed videos are used to record kinematics of bird flight, particularly barred owls and red-shouldered hawks during perching maneuvers, and compared with model aircraft performing similar maneuvers. Development of a perching glider and associated control laws to model the dynamics are used as a class project. Observations are used to determine what different species and sizes of birds share in their methods to approach a perch under similar conditions. Using fundamental flight dynamics, simplified models capable of predicting position, attitude, and velocity of the flier are developed and compared with the observations. By comparing the measured data from the videos and predicted and measured motions from the glider models, it is hoped that the students gain a better understanding of the complexity of unsteady aerodynamics and aeronautics and an appreciation for the beauty of avian flight.

Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control

Bulletin of the American Physical Society, Nov 25, 2013

Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control LIBIN DANIEL, J... more Experimental Study of the Power Profile Airfoil Equipped with Plasma Flow Control LIBIN DANIEL, JAMEY JACOB, Oklahoma State University -This presentation discusses results from an experimental study of the power profile airfoil at low Reynolds number. The power profile airfoil was developed by AMO Smith and consists of a blunt trailing edge shape with two wall jets near the trailing edge. The replacement of streamlining with properly designed blowing is used to prevent flow separation and additionally offers potential applications as a powered high-lift system, propulsive system, or low inertia control device. The 2D wind-tunnel model consists of the 22.5% thick power profile airfoil equipped with a movable trailing edge plug to direct flow along the trailing edge streamline. Compressed air was passed into the model via a plenum with flow conditioning devices to create pressure backdrop to allow uniform blowing at the trailing edge. The effects of varying jet momentum coefficient and trailing edge positioning on the aerodynamic characteristics are observed with both wake surveys and PIV. The impact of plasma synthetic jet actuators (PSJA) placed along the trailing edge of the power profile airfoil is also discussed. PSJA operation is compared to the baseline power profile airfoil both alone and working with the blowing to provide additional control authority.

Perching Dynamics and Development of a Simple Model

Bulletin of the American Physical Society, Nov 25, 2013

Wing Warping and Its Impact on Aerodynamic Efficiency

Bulletin of the American Physical Society, Nov 20, 2007

Wing Warping and Its Impact on Aerodynamic Efficiency BEN LOH, JAMEY JACOB, Oklahoma State Univer... more Wing Warping and Its Impact on Aerodynamic Efficiency BEN LOH, JAMEY JACOB, Oklahoma State University -Inflatable wings have been demonstrated in many applications such as UAVs, airships, and missile stabilization surfaces. A major concern presented by the use of an inflatable wing has been the lack of traditional roll control surfaces. This leaves the designer with several options in order to have control about the roll axis. Since inflatable wings have a semiflexible structure, wing warping is the obvious solution to this problem. The current method is to attach servos and control linkages to external surface of the wing that results in variation of profile chamber and angle of attack from leading edge or trailing edge deflection. Designs using internal muscles will also be discussed. This creates a lift differential between the half-spans, resulting in a roll moment. The trailing edge on the other half-span can also be deflected in the opposite direction to increase the roll moment as well as to reduce roll-yaw coupling. Comparisons show that higher L/D ratios are possible than using traditional control surfaces. An additional benefit is the ability to perform symmetric warping to achieve optimum aerodynamic performance. Via warping alone, an arbitrary span can be warped such that it has the same aerodynamic characteristics as an elliptical planform. Comparisons between lifting line theory and test results will be presented.

Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings

Bulletin of the American Physical Society, Nov 21, 2005

Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings ANDREW SIMPSON, SUZAN... more Wing Warping, Roll Control and Aerodynamic Optimization of Inflatable Wings ANDREW SIMPSON, SUZANNE SMITH, JAMEY JACOB, University of Kentucky -The research presents work on aerodynamic control by warping inflatable wings. Inflatable wings are deformable by their nature. Mechanical manipulation of the wing's shape has been demonstrated to alter the performance and control the vehicle in flight by deforming the trailing edge of the wing near the wing tip. Predicting and correlating the forces required in deforming the wings to a particular shape and the deformation generated for a given internal pressure were conducted through the use of photogrammetry. This research focuses on optimizing the roll moments and aerodynamic performance of the vehicle, given the current level of wing warping ability. Predictions from lifting line theory applied to wing shape changes are presented. Comparisons from the experimental results are made with lifting line analysis for wings with arbitrary twist and the solutions are used to determine rolling moment and optimum L/D. Results from flight tests will also be presented.

Thrust Vectoring Flow Control Using Plasma Actuators

Bulletin of the American Physical Society, Nov 20, 2007

Thrust Vectoring Flow Control Using Plasma Actuators JAMEY JACOB, MICHAEL BOLITHO, Oklahoma State... more Thrust Vectoring Flow Control Using Plasma Actuators JAMEY JACOB, MICHAEL BOLITHO, Oklahoma State University -Thrust vectoring flow control is demonstrated using plasma synthetic jet actuators (PSJA). The PSJA is a geometric variant of a plasma actuator, consisting of a symmetric electrode array that results in a circular region of dielectric barrier discharge plasma. Quiescent flow PIV measurements of the PSJA reveal that the flowfield on actuation resembles that of a zero-mass flux or synthetic jet that is useful for flow control, particularly separation reduction. Like synthetic jets, unsteady pulsed actuator operation results in formation of multiple vortex rings. The output jet momentum is found to be affected by the power input, actuator dimension and pulsing frequency. While increasing the input power increases the maximum jet velocity, an optimum range of pulsing frequencies and actuator dimensions are observed to exist in order to maximize jet momentum. By asymmetrically varying the plasma input parameters, such as frequency, amplitude and duty cycle, it is possible to control the jet angle. Vectoring using high frequency pusling akin to synthetic jets is more effective than vectoring by modifying steady control inputs and differences in control effectiveness are due primarily to the time scales associated with the vortex formation.

Characteristics of Plasma Synthetic Jet Actuators in Crossflow

Bulletin of the American Physical Society, Nov 19, 2006

Characteristics of Plasma Synthetic Jet Actuators in Crossflow ARVIND SANTHANAKRISHNAN, Universit... more Characteristics of Plasma Synthetic Jet Actuators in Crossflow ARVIND SANTHANAKRISHNAN, University of Kentucky, JAMEY JACOB, Oklahoma State University -The plasma synthetic jet actuator (PSJA) consists of two annular electrodes separated by dielectric material that results in a circular region of dielectric barrier discharge plasma. In quiescent conditions, this plasma ring produces a synthetic jet which can be used for active flow control applications. Unsteady pulsing of the actuator results in the formation of multiple primary and secondary vortex rings, the latter remaining fixed or trapped in space. The jet is observed to be formed by the advection and interaction of the primary vortices, resembling a conventional synthetic jet. This presentation examines the operation of the PSJA in a crossflow at three different jet to freestream velocity ratios. PIV measurements in the streamwise and cross-stream planes are used to illustrate the three dimensionality of the jet and associated vortical structures. The strength of the vortex ring is found to vary along its circumference due to interaction with the freestream. The boundary layer characteristics obtained from these experiments suggest that the mechanism of the PSJA in crossflow is similar to an active boundary layer trip. Both the penetration of the jet and effectiveness of the trip action are found to decrease with increase in freestream velocity. The effects of unsteady pulsing and increasing input power on actuator created crossflow vortices will also be presented.

Characterization of Zero Mass Flux Flow Control of Airfoil Separation at Low Re

Bulletin of the American Physical Society, Nov 20, 2005

Corotating Vortex Formation, Merger, and Modification

Bulletin of the American Physical Society, Nov 21, 2005

Corotating Vortex Formation, Merger, and Modification JAMEY JACOB, University of Kentucky -Experi... more Corotating Vortex Formation, Merger, and Modification JAMEY JACOB, University of Kentucky -Experimental results from a combined wind tunnel and tow tank study on the evolution, interaction, and merger of two corotating trailing vortices are presented. In the current study, NACA 0012 airfoils positioned at positive and negative angles of attack are used to generate a corotating vortex pair. Measurements with a seven-hole probe are used to extract 3-D velocity and pressure fields in the tunnel while PIV is used in the tow tank to measure 2-D velocity fields in the vortex wake. The semi-span length is varied in the experiments to investigate the effects of initial separation on vortex formation and merger. Experimental information of the vortex motion is compared with theoretical predictions. Comparison shows that at larger initial separations, the motion of the vortex pair is well estimated from the 2-D analysis, while at smaller separations, the motion of the vortex pair cannot be well predicted from the results of the line vortex assumption. Effects in forcing vortex breakup using a virtual winglet from a plasma actuator are presented. At sufficient power inputs, the virtual winglet can substantially modify the vortex circulation magnitude and distribution. Comparisons of information confidence and data quality are made between the two measurement techniques and facilities. Finally, comparisons of differences in the vortex roll-up and evolution due to initial separation changes are discussed and contrasted to that of a single tip vortex and corotating vortex pair on a wing with flap.

Evaluation of Cylindrical Asymmetric Surface Dielectric Barrier Discharge Actuators for Surface Decontamination and Mixing

Plasma, Nov 25, 2021

Surface dielectric barrier discharge (SDBD) was used to evaluate cylindrical plasma actuators for... more Surface dielectric barrier discharge (SDBD) was used to evaluate cylindrical plasma actuators for inactivation of Salmonella enterica. A cylindrical SDBD configuration was evaluated to determine if the inherent induced body force could be leveraged to impel plasma species, such as reactive oxygen and nitrogen species (RONS), as an apparatus to sterilize surfaces. The cylindrical structure is evaluated in this study to observe whether an increase in mixing is possible to efficiently distribute the plasma species, thereby improving bacterial inactivation efficiency. The increase in induced airflow of SDBD actuators with increased numbers of electrodes correlates with increased bacterial inactivation. These results suggest that improving the particle velocity, airflow mixing tendencies, and plasma volume for the same power inputs (same net power to the actuators) results in increased surface decontamination efficiency.

Real-Time Traffic End-of-Queue Detection and Tracking in UAV Video

arXiv (Cornell University), Jan 9, 2023

Highway work zones are susceptible to undue accumulation of motorized vehicles which calls for dy... more Highway work zones are susceptible to undue accumulation of motorized vehicles which calls for dynamic work zone warning signs to prevent accidents. The work zone signs are placed according to the location of the end-of-queue of vehicles which usually changes rapidly. The detection of moving objects in video captured by Unmanned Aerial Vehicles (UAV) has been extensively researched so far, and is used in a wide array of applications including traffic monitoring. Unlike the fixed traffic cameras, UAVs can be used to

Soil Moisture Monitoring Through UAS-Assisted Internet of Things LoRaWAN Wireless Underground Sensors

IEEE Access

With growing usage and demand for the global freshwater supply, there is an increasing need for t... more With growing usage and demand for the global freshwater supply, there is an increasing need for technologies that facilitate water conservation and environmental stewardship in irrigated agriculture. Toward this end, recent demonstrations of Internet of Things (IoT) sensors have revealed the value of wireless soil moisture content sensors. However, existing wireless solutions often employ above-ground wireless communication modules that physically interfere with routine farming operations. Underground wireless network solutions are severely challenged by the large radio-frequency (RF) propagation loss through soil. This paper presents a method that overcomes both problems by employing completely buried underground IoT sensors and communication modules with UAS (uncrewed aircraft system) mounted LoRaWAN gateways. The UAS mounted LoRaWAN gateway eliminates the need for any in-field base stations and also allows the LoRa enabled sensors to transmit data over short distances with very low energy. Field tests were carried out using this approach to serve as a proof of concept. The RSSI (received signal strength indicator) demonstrates that the proposed solution has good communication link margin and a significantly larger communication range than is necessary for reliable operation. Moreover, this solution is easy to build, scalable, cost-effective, and can be implemented in a highly power efficient fashion. 15 16 for monitoring soil moisture is preferable to avoid the cost and 38 complexity of laying and maintaining long lengths of cable. 39 In the wireless scheme, multiple sensors can be deployed in a 40 field to set up a wireless sensor network that can convey soil 41 moisture data from various parts of the field to the network 42 server. Several wireless technologies have been demonstrated 43 in this regard for precision agriculture, including GPRS (Gen-44 eral Packet Radio Service), GSM (Global System for Mobile 45 Communication), Wi-Fi, Bluetooth, and Zigbee [7]. In a 46 similar application, forest fire monitoring systems based on 47 Zigbee wireless sensors have also been demonstrated [8]. 48 The research challenges of wireless underground sensor 49 networks have been reviewed in [9]. If all sensor nodes and 50 communication modules can be placed completely under-51 ground, then devices can avoid interfering with farm machin-52 ery, a significant attraction. The main challenge of this 53 scheme is the high RF (radio frequency) path loss, which 54 causes low data rate for a given power, or high power con-55 sumption for a given data rate compared to above-ground 56 communication [9]. Data cannot be transported over long 57 distance in an underground sensor network without excessive 58 power use, so it must be re-routed relatively quickly to an 59 above-ground stationary or mobile base stations or gateways 60 [9]. This challenge is compensated by setting up a dense array 61 of above-ground base stations, which is neither cost-effective 62 nor practical. As a less traditional wireless solution, magnetic 63 induction was also investigated for underground communica-64 tion [10]. This technique leverages the lower material losses 65 of non-propagating magnetic fields for communication, but 66 also suffers a very short range due to the more rapid roll-off 67 of near-field power density. Underground magnetic induction 68 waveguide systems were subsequently investigated, which 69 proved that a large range can be achieved by employing a 70 large number of relay coils in short intervals between the 71 transmitter and receiver [11]. While feasible, this dramati-72 cally increases the complexity and cost of this solution. 73 More possible agricultural solutions have emerged under 74 the umbrella of the Internet of Things (IoT) -a vast network 75 of relatively simple devices such as sensors and cameras, 76 connected to the internet via (predominantly) wireless com-77 munication networks [12]. For example, [13] employed an 78 IoT-based wireless sensor network to develop a Greenhouse 79 Irrigation Management System to monitor various agricul-80 tural parameters including soil moisture. It is significant to 81 this work that a variant of IoT called the Internet of Under-82 ground Things (IoUT) has developed with applications in 83 agriculture wherein interconnected things are partially or 84 completely placed underground [14]. 85 LoRa is a wireless radio technology and LoRaWAN is a 86 wide area network protocol that incorporates the LoRa tech-87 nology [15]. In IoT applications, the LoRaWAN (Low Range 88 Wide Area Network), or just LoRa, protocol has emerged as 89 a very promising technology since it allows long range, low 90 data rate wireless communication utilizing very low power 91 LoRa enabled sensors [16]. After analyzing many different 92 technologies, some researchers have concluded that for smart 93

Evaluation of Onboard Detect-and-Avoid System for sUAS BVLOS Operations

International Journal of Aviation, Aeronautics, and Aerospace

Small Unmanned Aircraft Systems (sUAS) have expanded rapidly in the past few years due to their a... more Small Unmanned Aircraft Systems (sUAS) have expanded rapidly in the past few years due to their ability to greatly expand commercial and civilian aviation capabilities. As growth continues, many sUAS operations will require coexistence with other aircraft operating within the National Airspace System (NAS). For now, sUAS and other Advanced Air Mobility (AAM) solutions currently have restricted access to the NAS for their inability to detect-and-avoid other air traffic. Safety is the primary concern and the critical challenge to overcome among many regulatory and technological (sensing, command, control, and communication) hurdles prior to full AAM integration into the NAS. The Federal Aviation Administration (FAA), the United States national aviation authority, calls for a target level of safety equivalent to the manned aircraft see-and-avoid requirement (FAA, 2021). Unmanned Traffic Management (UTM) and Detect-And-Avoid (DAA) are two major obstacles in incorporating sUAS into NAS. A successful UTM strategy will keep sUAS traffic secure and effective. DAA is a key component to a successful UTM system, which can be used by sUAS to track and avoid obstacles, other aircraft, and each other. For sUAS to provide the essential target level of safety, DAA systems will be required to be robust and reliable. Detection systems and associated trackers, collision detection, risk assessment, collision avoidance, and self-separation algorithms are typically included in a complete working DAA system. Despite their limited capabilities, vision-based DAA systems are becoming more common due to their light weight and low cost. In addition, they provide more information about the environment than other available sensors, making them ideal for sUAS with limited payload power. Over the years the need and use of sUAS has expanded into avenues that have changed the way corporate, military, commercial sectors are able to do business. This includes operating sUAS in locations that are hard for humans to reach or requires extensive equipment investment to do the job. To operate in the NAS, federal restrictions require sUAS to perform similarly to manned aircraft. For unmanned aircraft to maintain separation in congested airspace, this presents the difficult issue of not having the human pilot as the last line of defense. Therefore, DAA systems must achieve a level of safety that is equivalent to manned pilots or better, while balancing size, weight, and power constraints to maintain economic viability. This research is the 6th installment to be completed and published by the core research team. Previous studies focused on detecting and assessing the collision potential of manned aircraft and sUAS by Visual Observers