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At least 415 records · Page 23

Sensing Small Uncrewed Aerial Vehicles with Distributed Radars for Advanced Air Mobility Surveillance

In the context of Advanced and Urban Air Mobility major attention is being reserved to the development of sensing strategies for small Uncrewed Aerial Vehicles (sUAVs) to enable their safe operations in and around urban areas. Such strategies should rely on non-cooperative distributed sensors to strengthen the surveillance solution towards the unreliability of Global Navigation Satellite System (GNSS) positioning information, which is typical for low-altitude-flying platforms in urban regions, and increase the monitored airspace volume. To this aim, this paper proposes a fusion solution for a network of distributed ground-based radars, which can be exploited to not only increase the coverage over large airspace volumes but also improve the overall detectability and traceability of sUAVs by leveraging on multiple views over the same area. The solution exploits a centralized fusion scheme in which measurements collected by each radar are shared with a Fusion Center where Kalman Filtering is exploited to build a unique, fused track. Tests conducted on experimental data collected using two sUAVs as flying targets and three distributed radars showed that the proposed solution can produce an increase in coverage from about 20 % (single radar configuration) to about 80 % of the targets’ flight path, as well as a finer accuracy yielding meter and meter-per-second root mean square error values on position and velocity components.

Federica Vitiello↗

Oxidant and precursor trends in the metropolitan Los Angeles region

This paper describes recent historical trends in oxidant and precursors in the Los Angeles region. Control strategies and basinwide emission trends for nitrogen oxides and reactive hydrocarbons are documented year by year from 1965 to 1974. Trends in the geographic distribution of emissions are illustrated by computing net percentage emission changes over the decade for individual counties. The changes in emissions are compared with changes in ambient precursor concentrations and oxidant concentrations. We find that many of the changes in monitored air quality can be explained by trends in both total emissions and the spatial distribution of emissions.

Trijonis, J.↗

The synthesis and analysis of color images

A method is described for performing the synthesis and analysis of digital color images. The method is based on two principles. First, image data are represented with respect to the separate physical factors, surface reflectance and the spectral power distribution of the ambient light, that give rise to the perceived color of an object. Second, the encoding is made efficient by using a basis expansion for the surface spectral reflectance and spectral power distribution of the ambient light that takes advantage of the high degree of correlation across the visible wavelengths normally found in such functions. Within this framework, the same basic methods can be used to synthesize image data for color display monitors and printed materials, and to analyze image data into estimates of the spectral power distribution and surface spectral reflectances. The method can be applied to a variety of tasks. Examples of applications include the color balancing of color images, and the identification of material surface spectral reflectance when the lighting cannot be completely controlled.

Wandell, B. A.↗

The synthesis and analysis of color images

A method is described for performing the synthesis and analysis of digital color images. The method is based on two principles. First, image data are represented with respect to the separate physical factors, surface reflectance and the spectral power distribution of the ambient light, that give rise to the perceived color of an object. Second, the encoding is made efficiently by using a basis expansion for the surface spectral reflectance and spectral power distribution of the ambient light that takes advantage of the high degree of correlation across the visible wavelengths normally found in such functions. Within this framework, the same basic methods can be used to synthesize image data for color display monitors and printed materials, and to analyze image data into estimates of the spectral power distribution and surface spectral reflectances. The method can be applied to a variety of tasks. Examples of applications include the color balancing of color images, and the identification of material surface spectral reflectance when the lighting cannot be completely controlled.

Wandell, Brian A.↗

New Perspectives for Watering Substrate-Based Root Modules in Microgravity in the Advanced Plant Habitat (APH)

The Advanced Plant Habitat (APH) was installed on the International Space Station (ISS) in October 2017. Following a successful EVT (Experiment Verification Test) study at Kennedy Space Center (KSC), using Arabidopsis lines with varying levels of lignin, two inaugural studies were carried out on ISS in 2018 under the same experimental design, with the corresponding ground controls at KSC. The APH for this study deploys a substrate-based root module designed for plant growth in microgravity. Upon experiment initiation (such as for the EVT), the root module is primed (liquid imbibition) by flooding the root zone to initiate seed germination and to remove air from the porous tubing and particulate media. In the APH ISS inaugural study, the speed of supplying water to initially dry media was found to adversely affect the overall moisture distribution within the root module in microgravity (but not at 1g). Non-destructive estimations of Arabidopsis plant growth were carried out by monitoring changes in rosette leaf area on a daily basis. These data indicated that the original priming procedure caused patchy moisture distribution that affected plant growth and survival. An improved methodology for priming the second root module of PH-01 was devised and implemented in the second experiment. Leaf area and color estimates suggested that the modified priming scheme improved moisture distribution and plant growth. These data, when compared with the EVT study, suggest that nondestructive measurements of plant growth can aid towards optimization of plant growth conditions in microgravity.

Monje O.↗

The MIST /MIUS Integration and Subsystems Test/ laboratory - A testbed for the MIUS /Modular Integrated Utility System/ program

The MIUS (Modular Integrated Utility System) concept is to be an energy-conserving, economically feasible, integrated community utility system to provide five necessary services: electricity generation, space heating and air conditioning, solid waste processing, liquid waste processing, and residential water purification. The MIST (MIUS Integration and Subsystem Test) integrated system testbed constructed at the Johnson Space Center in Houston includes subsystems for power generation, heating, ventilation, and air conditioning (HVAC), wastewater management, solid waste management, and control and monitoring. The key design issues under study include thermal integration and distribution techniques, thermal storage, integration of subsystems controls and displays, incinerator performance, effluent characteristics, and odor control.

Beckham, W. S., Jr.↗

Remote measurement of aerosol particle characteristics and their significance to meteorology

Theoretical models for the calculation of the radiative effects of atmospheric aerosols require the inference of such parameters as optical depth, the complex index of refraction and the equivalent size distribution. A polarimeter and a multispectral radiometer are used for local monitoring of aerosols via ground stations, or global monitoring via spacecraft occultation experiments. It is shown that measurements of optical depth at one wavelength as has been the custom, are insufficient to provide useful information for meteorological calculations, and new experiments and instruments must be devised to take advantage of new theoretical developments.

Kuriyan, J. G.↗

Monitoring of particulate contamination and background brightness from IECM based instrumentation

Of particular concern to the astronomical community is the effect of Shuttle Transportation System induced contamination in the form of individual particles and general background on astronomical experiments. In an effort to investigate this problem, two camera/photometers in the Induced Environment Contamination Monitor (IECM) will be used to determine the size and velocity distribution of contaminant particles, their origin, and the extent of sunlit background brightness resulting from spacecraft contamination. The cameras will operate synchronously as a stereo pair to make continuous photographic measurements throughout the missions.

Clifton, K. S.↗

MODIS information, data and control system (MIDACS) operations concepts

The MODIS Information, Data, and Control System (MIDACS) Operations Concepts Document provides a basis for the mutual understanding between the users and the designers of the MIDACS, including the requirements, operating environment, external interfaces, and development plan. In defining the concepts and scope of the system, how the MIDACS will operate as an element of the Earth Observing System (EOS) within the EosDIS environment is described. This version follows an earlier release of a preliminary draft version. The individual operations concepts for planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, data archive and distribution, and user access do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams are not yet formed; however, it is possible to develop the operations concepts based on the present concept of EosDIS, the level 1 and level 2 Functional Requirements Documents, and through interviews and meetings with key members of the scientific community. The operations concepts were exercised through the application of representative scenarios.

Han, D.↗

Volcanic thermal features observed by AVIRIS

In July 1991, Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) was flown over Mount Etna and Stromboli, Italy. Lava-filled vents were then present within summit craters of both volcanoes. Since surfaces at magmatic temperatures radiate strongly over the wavelength ranges of the AVIRIS C- and D-spectrometers, it was hoped that the data collected would reveal clear thermal signatures, even of sub-pixel sized features, as have been observed in the 1.65 and 2.22 microns bands of Landsat Thematic Mapper images. This would provide an opportunity to explore the potential of imaging spectrometers for deriving temperature distributions of hot volcanic surfaces. Such research has implications for volcano monitoring in the EOS era, and also for any future AVIRIS deployments above active lava flows, lakes, and domes, where understanding of their behavior may be advanced by detailed thermal observations.

Oppenheimer, Clive↗

The new Be-type star HD 147196 in the Rho Ophiuchi dark cloud region

The newly discovered hot-emission line star, HD 147196 in the Rho Oph dark cloud region was observed spectroscopically and photometrically and high and low resolution IUE spectra were obtained. The finding of Irvine (1990) that this relatively bright star show its H-alpha-line in emission is confirmed. Previous H-alpha-surveys of the Rho Oph star-forming region did not detect HD 147196 as an H-alpha-emission star, meaning that it must recently be very active and has perhaps transformed itself from a B-type star at shell phase to a Be-phase. The Mg II h + k resonance lines are in absorption and they appear to be interstellar in nature, which means that either the abundance of Mg in the extended atmosphere of the star is low or that the shell is not extended enough to produce emission lines of Mg II. Photometric observations of this B8 V type star do not show any variations during at least the years covered by our monitoring or any excess of NIR radiation in its spectral energy distribution up to the M-passband at 4.8 microns.

The, P. S.↗

Application of World Wide Web (W3) Technologies in Payload Operations

World Wide Web (W3) technologies are considered in relation to their application to space missions. It is considered that such technologies, including the hypertext transfer protocol and the Java object-oriented language, offer a powerful and relatively inexpensive framework for distributed application software development. The suitability of these technologies for payload monitoring systems development is discussed, and the experience gained from the development of an insect habitat monitoring system based on W3 technologies is reported.

Sun, Charles↗

Glenn's Telescience Support Center Provided Around-the-Clock Operations Support for Space Experiments on the International Space Station

NASA Glenn Research Center s Telescience Support Center (TSC) allows researchers on Earth to operate experiments onboard the International Space Station (ISS) and the space shuttles. NASA s continuing investment in the required software, systems, and networks provides distributed ISS ground operations that enable payload developers and scientists to monitor and control their experiments from the Glenn TSC. The quality of scientific and engineering data is enhanced while the long-term operational costs of experiments are reduced because principal investigators and engineering teams can operate their payloads from their home institutions.

Malarik, Diane C.↗

Flight Hardware Fabricated for Combustion Science in Space

NASA Glenn Research Center s Telescience Support Center (TSC) allows researchers on Earth to operate experiments onboard the International Space Station (ISS) and the space shuttles. NASA s continuing investment in the required software, systems, and networks provides distributed ISS ground operations that enable payload developers and scientists to monitor and control their experiments from the Glenn TSC. The quality of scientific and engineering data is enhanced while the long-term operational costs of experiments are reduced because principal investigators and engineering teams can operate their payloads from their home institutions.

OMalley, Terence F.↗

Tunable Optical Assembly with Vibration Dampening

Since their market introduction in 1995, fiber Bragg gratings (FBGs) have emerged as excellent means of measuring such parameters as strain and temperature. Distributed-grating sensing is particularly beneficial for such structural-health monitoring applications such as those of 'smart' structures or integrated vehicle health management in aerospace vehicles. Because of the variability of their output wavelengths, tunable lasers have become widely used as means of measuring FBGs. Several versions of a lightweight assembly for strain-tuning an FBG and dampening its vibrations have been constructed. The main components of such an assembly are one or more piezoelectric actuators, an optical fiber containing one or more Bragg grating(s), a Bragg-grating strain-measurement system, and a voltage source for actuation. The piezoelectric actuators are, more specifically, piezoceramic fiber composite actuators and, can be, still more specifically, of a type known in the art as macro-fiber composite (MFC) actuators. In fabrication of one version of the assembly, the optical fiber containing the Bragg grating(s) is sandwiched between the piezoelectric actuators along with an epoxy that is used to bond the optical fiber to both actuators, then the assembly is placed in a vacuum bag and kept there until the epoxy is cured. Bonding an FBG directly into an MFC actuator greatly reduces the complexity, relative to assemblies, that include piezoceramic fiber composite actuators, hinges, ferrules, and clamp blocks with setscrews. Unlike curved actuators, MFC actuators are used in a flat configuration and are less bulky. In addition, the MFC offers some vibration dampening and support for the optical fiber whereas, in a curved piezoelectric actuator assembly, the optical fiber is exposed, and there is nothing to keep the exposed portion from vibrating.

Shams, Qamar A.↗

Overview of the LADEE Ultraviolet-visible Spectrometer: Design, Performance and Planned Operations

The Lunar Atmosphere and Dust Environment Explorer (LADEE) is an orbital lunar science mission currently under development to address the goals of the 2003 National Research Council decadal survey, the Lunar Exploration Analysis Group Roadmap, and the "Scientific Context for Exploration of the Moon" (SCEM) report, and has been recommended for execution by the 2011 Planetary Missions Decadal Survey. The mission s focus is to study the pristine state of the lunar atmosphere and dust environment prior to possible lunar exploration activities by countries, including the United States, China, India, and Japan, among others. Activity on the lunar surface has the potential of altering the tenuous lunar atmosphere, but changing the type and concentration of gases in the atmosphere. Before these activities occur it is important to make measurements of the current lunar atmosphere in its unmodified state. LADEE will determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. It will monitor variations in known gases, such as sodium, potassium, argon and helium, and will search for other, as-yet-undetected gases of both lunar and extra-lunar origin. LADEE will also determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability. Launch is planned for August, 2013.

Colaprete, A.↗

Observations of Titanium, Aluminum and Magnesium in the Lunar Exosphere by LADEE UVS

The Lunar Atmosphere and Dust Environment Explorer (LADEE) was an orbital lunar science mission designed to address the goals of the 2003 National Research Council decadal survey, the Lunar Exploration Analysis Group Roadmap, and the "Scientific Context for Exploration of the Moon" (SCEM) report, and has been recommended for execution by the 2011 Planetary Missions Decadal Survey. The LADEE mission goal was to determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. It will monitor variations in known gasses, such as sodium, potassium, argon and helium, and will search for other, as-yet-undetected gasses of both lunar and extra-lunar origin. Another goal of LADEE was to determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability.

The Ultraviolet-Visible Spectrometer (UVS)↗

Smart Sensor Systems for Human Health and Environmental Applications

Sensors and sensor systems are central to providing improved awareness of an individual's health state and surroundings. This presentation describes efforts to develop Smart Sensor Systems for a range of health and safety applications moving towards distributed intelligence. This includes efforts to develop a human health breath monitoring system using this microsensor Smart Sensor System approach. The same core technology can be used for a range of applications related to improved human health and environmental monitoring. Other examples of human health relevant technology development will also be given.

Smart Sensors Health↗