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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

High Altitude Long Endurance Air Vehicle Analysis of Alternatives and Technology Requirements Development

The objective of this study was to develop a variety of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) conceptual designs for two operationally useful missions (hurricane science and communications relay) and compare their performance and cost characteristics. Sixteen potential HALE UAV configurations were initially developed, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative (SR) propulsion systems. Through an Analysis of Alternatives (AoA) down select process, the two leading consumable fuel configurations (one each from the HTA and LTA alternatives) and an HTA SR configuration were selected for further analysis. Cost effectiveness analysis of the consumable fuel configurations revealed that simply maximizing vehicle endurance can lead to a sub-optimum system solution. An LTA concept with a hybrid propulsion system (solar arrays and a hydrogen-air proton exchange membrane fuel cell) was found to have the best mission performance; however, an HTA diesel-fueled wing-body-tail configuration emerged as the preferred consumable fuel concept because of the large size and technical risk of the LTA concept. The baseline missions could not be performed by even the best HTA SR concept. Mission and SR technology trade studies were conducted to enhance understanding of the potential capabilities of such a vehicle. With near-term technology SR-powered HTA vehicles are limited to operation in favorable solar conditions, such as the long days and short nights of summer at higher latitudes. Energy storage system specific energy and solar cell efficiency were found to be the key technology areas for enhancing HTA SR performance.

Nickol, Craig L.↗
NASA NTRS2006

Wireless Command-and-Control of UAV-Based Imaging LANs

Dual airborne imaging system networks were operated using a wireless line-of-sight telemetry system developed as part of a 2002 unmanned aerial vehicle (UAV) imaging mission over the USA s largest coffee plantation on the Hawaiian island of Kauai. A primary mission objective was the evaluation of commercial-off-the-shelf (COTS) 802.11b wireless technology for reduction of payload telemetry costs associated with UAV remote sensing missions. Predeployment tests with a conventional aircraft demonstrated successful wireless broadband connectivity between a rapidly moving airborne imaging local area network (LAN) and a fixed ground station LAN. Subsequently, two separate LANs with imaging payloads, packaged in exterior-mounted pressure pods attached to the underwing of NASA's Pathfinder-Plus UAV, were operated wirelessly by ground-based LANs over independent Ethernet bridges. Digital images were downlinked from the solar-powered aircraft at data rates of 2-6 megabits per second (Mbps) over a range of 6.5 9.5 km. An integrated wide area network enabled payload monitoring and control through the Internet from a range of ca. 4000 km during parts of the mission. The recent advent of 802.11g technology is expected to boost the system data rate by about a factor of five.

Herwitz, Stanley↗
NASA NTRS2007

High Altitude Long Endurance UAV Analysis of Alternatives and Technology Requirements Development

An Analysis of Alternatives and a Technology Requirements Study were conducted for two mission areas utilizing various types of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicles (UAV). A hurricane science mission and a communications relay mission provided air vehicle requirements which were used to derive sixteen potential HALE UAV configurations, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative propulsion systems. A HTA diesel-fueled wing-body-tail configuration emerged as the preferred concept given near-term technology constraints. The cost effectiveness analysis showed that simply maximizing vehicle endurance can be a sub-optimum system solution. In addition, the HTA solar regenerative configuration was utilized to perform both a mission requirements study and a technology development study. Given near-term technology constraints, the solar regenerative powered vehicle was limited to operations during the long days and short nights at higher latitudes during the summer months. Technology improvements are required in energy storage system specific energy and solar cell efficiency, along with airframe drag and mass reductions to enable the solar regenerative vehicle to meet the full mission requirements.

Nickol, Craig L.↗
NASA NTRS2007

Update on Piloted and Un-Piloted Aircraft at NASA Dryden

This viewgraph presentation reviews the NASA Dryden Flight Research Center's (DFRC) environment for testing of experimental aircraft. Included are a satellite view of the Dryden locale, and a summary of the capabilities at DFRC. It reviews the capabilites of High Altitude Platform (HAP) testing; Gulfstream III (1.)Unmanned Aerial Vehicle (UAV) synthetic aperture radar (SAR) (2) Precision Trajectory Capability Global Hawk (ACTD); ER-2; Ikhana (Predator B);

DelFrate, John H.↗
NASA NTRS2007

Small UAV Research and Evolution in Long Endurance Electric Powered Vehicles

This paper describes recent research into the advancement of small, electric powered unmanned aerial vehicle (UAV) capabilities. Specifically, topics include the improvements made in battery technology, design methodologies, avionics architectures and algorithms, materials and structural concepts, propulsion system performance prediction, and others. The results of prototype vehicle designs and flight tests are discussed in the context of their usefulness in defining and validating progress in the various technology areas. Further areas of research need are also identified. These include the need for more robust operating regimes (wind, gust, etc.), and continued improvement in payload fraction vs. endurance.

Logan, Michael J.↗
NASA NTRS2007

A Turbine-powered UAV Controls Testbed

The latest version of the NASA Flying Controls Testbed (FLiC) integrates commercial-off-the-shelf components including airframe, autopilot, and a small turbine engine to provide a low cost experimental flight controls testbed capable of sustained speeds up to 200 mph. The series of flight tests leading up to the demonstrated performance of the vehicle in sustained, autopiloted 200 mph flight at NASA Wallops Flight Facility's UAV runway in August 2006 will be described. Earlier versions of the FLiC were based on a modified Army target drone, AN/FQM-117B, developed as part of a collaboration between the Aviation Applied Technology Directorate at Fort Eustis, Virginia and NASA Langley Research Center. The newer turbine powered platform (J-FLiC) builds on the successes using the relatively smaller, slower and less expensive unmanned aerial vehicle developed specifically to test highly experimental flight control approaches with the implementation of C-coded experimental controllers. Tracking video was taken during the test flights at Wallops and will be available for presentation at the conference. Analysis of flight data from both remotely piloted and autopiloted flights will be presented. Candidate experimental controllers for implementation will be discussed. It is anticipated that flight testing will resume in Spring 2007 and those results will be included, if possible.

Motter, Mark A.↗
NASA NTRS2007

G-III Precision Autopilot Development in Support of UAVSAR Program

This viewgraph presentation reviews NASA Dryden's role in the UAVSAR Program. The primary objective of the UAVSAR Project is to develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for use on an unmanned aerial vehicle (UAV) or minimally piloted vehicle. Dryden's work in developing the Platform Precision Autopilot (PPA) capability is described in this presentation. The goal for the development is that the PPA shall fly the G-III within a 10 m (32.8 ft) diameter tube for at least 90% of each data take in conditions of calm to light atmospheric disturbances, as defined. The G-III aircraft is descrbed, the test plan is outlined, and the initial test results are reviewed.

Lee, James↗
NASA NTRS2007

G-III Precision Autopilot Development in Support of UAVSAR Program

The primary objective of the UAVSAR Project is to develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for use on an unmanned aerial vehicle (UAV) or minimally piloted vehicle. This viewgraph presentation reviews NASA Dryden's role in the UAVSAR program. The G-III aircraft is described and shown, as well as a high level system architecture. The goals of the Platform Precision Autopilot (PPA) that it are shall fly the G-III within a 10 m (32.8 ft) diameter tube for at least 90% of each data take in conditions of calm to light atmospheric disturbances, as defined in MIL-STD-1797. That it minimize motion during data collection. It is critical to operate the UAVSAR System on a steady platform.

Lee, James↗
NASA NTRS2007

NASA Experience with UAS Science Applications

Viewgraphs of NASA's Unmanned Aerial Systems (UAS) as it applies to Earth science missions is presented. The topics include: 1) Agenda; 2) Background; 3) NASA Science Aircraft Endurance; 4) Science UAS Development Challenges; 5) USCG Alaskan Maritime Surveillance; 6) NOAA/NASA UAV Demonstration Project; 7) Western States Fire Mission; 8) Esperanza Fire Emergency Response; 9) Ikhana (Predator B); 10) UAV Synthetic Aperture Radar (UAVSAR); 11) Global Hawk; and 12) Related Technologies

Curry, Robert E.↗
NASA NTRS2007

Ikhana: A NASA UAS Supporting Long Duration Earth Science Missions

The NASA Ikhana unmanned aerial vehicle (UAV) is a General Atomics Ae ronautical Systems Inc. (San Diego, California) MQ-9 Predator-B modif ied to support the conduct of Earth science missions for the NASA Sci ence Mission Directorate and, through partnerships, other government agencies and universities. It can carry over 2000 lb of experiment p ayloads in the avionics bay and external pods and is capable of missi on durations in excess of 24 hours at altitudes above 40,000 ft. The aircraft is remotely piloted from a mobile ground control station (GC S) that is designed to be deployable by air, land, or sea. On-board s upport capabilities include an instrumentation system and an Airborne Research Test System (ARTS). The Ikhana project will complete GCS d evelopment, science support systems integration, external pod integra tion and flight clearance, and operations crew training in early 2007 . A large-area remote sensing mission is currently scheduled for Summ er 2007.

Cobleigh, B.↗
NASA NTRS2007

A Web 2.0 and OGC Standards Enabled Sensor Web Architecture for Global Earth Observing System of Systems

This paper will describe the progress of a 3 year research award from the NASA Earth Science Technology Office (ESTO) that began October 1, 2006, in response to a NASA Announcement of Research Opportunity on the topic of sensor webs. The key goal of this research is to prototype an interoperable sensor architecture that will enable interoperability between a heterogeneous set of space-based, Unmanned Aerial System (UAS)-based and ground based sensors. Among the key capabilities being pursued is the ability to automatically discover and task the sensors via the Internet and to automatically discover and assemble the necessary science processing algorithms into workflows in order to transform the sensor data into valuable science products. Our first set of sensor web demonstrations will prototype science products useful in managing wildfires and will use such assets as the Earth Observing 1 spacecraft, managed out of NASA/GSFC, a UASbased instrument, managed out of Ames and some automated ground weather stations, managed by the Forest Service. Also, we are collaborating with some of the other ESTO awardees to expand this demonstration and create synergy between our research efforts. Finally, we are making use of Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) suite of standards and some Web 2.0 capabilities to Beverage emerging technologies and standards. This research will demonstrate and validate a path for rapid, low cost sensor integration, which is not tied to a particular system, and thus be able to absorb new assets in an easily evolvable, coordinated manner. This in turn will help to facilitate the United States contribution to the Global Earth Observation System of Systems (GEOSS), as agreed by the U.S. and 60 other countries at the third Earth Observation Summit held in February of 2005.

Mandl, Daniel↗
NASA NTRS2007

UAVSAR System Overview

The Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) project began as an Instrument Incubator Program (IIP) out of the NASA ESTO Program Office. After a year of study JPL presented to NASA an instrument concept that could be accommodated on the desired class of platforms, that would meet the original IIP science and instrument objectives and could be expanded to meet future airborne radar science needs. The UAVSAR project is a four year program consisting of a 3 year phase in which the radar system is designed and fabricated, the platform is modified, radar is installed on the aircraft and an initial flight testing program is begun. The last year of the program is designed to collect repeat pass data, to improve system robustness and to validate that the scientific objectives of the sensor are being met.

Cutler, Frank↗
NASA NTRS2007

X-Band Radar for Studies of Tropical Storms from High Altitude UAV Platform

The increased role of unmanned aerial vehicles (UAV) in NASA's suborbital program has created a strong interest in the development of instruments with new capabilities, more compact sizes and reduced weights than the instruments currently operated on manned aircrafts. There is a strong demand and tremendous potential for using high altitude UAV (HUAV) to carry weather radars for measurements of reflectivity and wind fields from tropical storms. Tropical storm genesis frequently occurs in ocean regions that are inaccessible to piloted aircraft due to the long off shore range and the required periods of time to gather significant data. Important factors of interest for the study of hurricane genesis include surface winds, profiled winds, sea surface temperatures, precipitation, and boundary layer conditions. Current satellite precipitation and surface wind sensors have resolutions that are too large and revisit times that are too infrequent to study this problem. Furthermore, none of the spaceborne sensors measure winds within the storm itself. A dual beam X-band Doppler radar, UAV Radar (URAD), is under development at the NASA Goddard Space Flight Center for the study of tropical storms from HUAV platforms, such as a Global Hawk. X-band is the most desirable frequency for airborne weather radars since these can be built in a relatively compact size using off-the-shelf components which cost significantly less than other higher frequency radars. Furthermore, X-band radars provide good sensitivity with tolerable attenuation in storms. The low-cost and light-weight URAD will provide new capabilities for studying hurricane genesis by analyzing the vertical structure of tropical cyclones as well as 3D reflectivity and wind fields in clouds. It will enable us to measure both the 3D precipitation structure and surface winds by using two antenna beams: fixed nadir and conical scanning each produced by its associated subsystem. The nadir subsystem is a magnetron based radar modified from a marine radar transceiver. It is capable of measuring vertical reflectivity and velocity profile while being a lower-cost, smaller size, and lighter weight version of the NASA ER-2 Doppler Radar (EDOP), which has flown during many NASA field campaigns and has provided valuable scientific information on hurricanes and weather phenomena. Unfortunately, EDOP is too large and heavy for most UAV platforms, but the experience gained with this instrument provided us with the heritage to build a new low-cost, light-weight, smaller system that will be capable of flying on UAVs. The scanning subsystem uses a TWT transmitter and provides measurements of 3D reflectivity/wind fields in-clouds. Conical scanning of the radar beam at a 35 deg. incidence angle will also provide information of surface wind speed and direction derived from the surface return over a single 360 deg. sweep. URAD data system will be Linux based with the capability of autonomous operation. It will utilize cutting edge digital receiver and FPGA technologies to carry out the data acquisition and processing tasks. High speed navigation data from the aircraft will also be captured and saved along with radar data for 3D measurement field reconstruction and aircraft motion correction. There is a tremendous potential for UAVs to carry down-looking weather radars for measurements of reflectivity, horizontal and vertical winds from tropical storms. With operation from HUAV platforms, the dual beam X-band radar under development promises to provide greatly needed information for tropical storm research.

Rodriquez, Shannon↗
NASA NTRS2007

G-III Precision Autopilot Development in Support of UAVSAR Program

The primary objective of the UAVSAR Project is to develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for use on an unmanned aerial vehicle (UAV) or minimally piloted vehicle. Five Cycle 1 precision autopilot flights have been completed as of May 14, 2007. The first flight was open-loop controller, the second, third, fourth, and fifth flights were closed loop. The fifth flight demonstrated increasing duration within ten meter tube (approximately 90% of the time in the ten meter tube over a 200km course).

Lee, James↗
NASA NTRS2007

Autonomous Soaring

This viewgraph presentation reviews the autonomous soaring flight of unmanned aerial vehicles (UAV). It reviews energy sources for UAVs, and two examples of UAV's that used alternative energy sources, and thermal currents for soaring. Examples of flight tests, plans, and results are given. Ultimately, the concept of a UAV harvesting energy from the atmosphere has been shown to be feasible with existing technology.

Lin, Victor P.↗
NASA NTRS2007

Methods and systems for detection of ice formation on surfaces

A system for detecting ice formation on metal, painted metal and other material surfaces can include a transparent window having an exterior surface upon which ice can form; a light source and optics configured and arranged to illuminate the exterior surface of the window from behind the exterior surface; and a detector and optics configured and arranged to receive light backscattered by the exterior surface and any ice disposed on the exterior surface and determine the thickness of the ice layer. For example, the system can be used with aircraft by placing one or more windows in the wings of the aircraft. The system is used for a novel optical method for real-time on-board detection and warning of ice formation on surfaces of airplanes, unmanned aerial vehicles (UAVs), and other vehicles and stationary structures to improve their safety and operation.

Alfano, Robert R.↗
NASA NTRS2007

Automated Target Planning for FUSE Using the SOVA Algorithm

The SOVA algorithm was originally developed under the Resilient Systems and Operations Project of the Engineering for Complex Systems Program from NASA s Aerospace Technology Enterprise as a conceptual framework to support real-time autonomous system mission and contingency management. The algorithm and its software implementation were formulated for generic application to autonomous flight vehicle systems, and its efficacy was demonstrated by simulation within the problem domain of Unmanned Aerial Vehicle autonomous flight management. The approach itself is based upon the precept that autonomous decision making for a very complex system can be made tractable by distillation of the system state to a manageable set of strategic objectives (e.g. maintain power margin, maintain mission timeline, and et cetera), which if attended to, will result in a favorable outcome. From any given starting point, the attainability of the end-states resulting from a set of candidate decisions is assessed by propagating a system model forward in time while qualitatively mapping simulated states into margins on strategic objectives using fuzzy inference systems. The expected return value of each candidate decision is evaluated as the product of the assigned value of the end-state with the assessed attainability of the end-state. The candidate decision yielding the highest expected return value is selected for implementation; thus, the approach provides a software framework for intelligent autonomous risk management. The name adopted for the technique incorporates its essential elements: Strategic Objective Valuation and Attainability (SOVA). Maximum value of the approach is realized for systems where human intervention is unavailable in the timeframe within which critical control decisions must be made. The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, launched in 1999, has been collecting science data for eight years.[1] At its beginning of life, FUSE had six gyros in two IRUs and four reaction wheels. Over time through various failures, the satellite has been left with one reaction wheel on the vehicle skew axis and two gyros. To remain operational, a control scheme has been implemented using the magnetic torque rods and the remaining momentum wheel.[2] As a consequence, there are attitude regions where there is insufficient torque authority to overcome environmental disturbances (e.g. gravity gradient torques). The situation is further complicated by the fact that these attitude regions shift inertially with time as the spacecraft moves through earth s magnetic field during the course of its orbit. Under these conditions, the burden of planning targets and target-to-target slew maneuvers has increased significantly since the beginning of the mission.[3] Individual targets must be selected so that the magnetic field remains roughly aligned with the skew wheel axis to provide enough control authority to the other two orthogonal axes. If the field moves too far away from the skew axis, the lack of control authority allows environmental torques to pull the satellite away from the target and can potentially cause it to tumble. Slew maneuver planning must factor the stability of targets at the beginning and end, and the torque authority at all points along the slew. Due to the time varying magnetic field geometry relative to any two inertial targets, small modifications in slew maneuver timing can make large differences in the achievability of a maneuver.

Heatwole, Scott↗