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open access

On identifying the specular reflection of sunlight in earth-monitoring satellite data.

Description: Among the background signals commonly seen by Earth-monitoring satellites is the specular reflection of sunlight off of Earth's surface, commonly referred to as a glint. This phenomenon, involving liquid or ice surfaces, can result in the brief, intense illumination of satellite sensors appearing from the satellite perspective to be of terrestrial origin. These glints are important background signals to be able to identify with confidence, particularly in the context of analyzing data from satellites monitoring for transient surface or atmospheric events. Here we describe methods for identifying glints based on the physical processes involved in their production, including spectral fitting and polarization measurements. We then describe a tool that, using the WGS84 spheroidal Earth model, finds the latitude and longitude on Earth where a reflection of this type could be produced, given input Sun and satellite coordinates. This tool enables the user to determine if the surface at the solution latitude and longitude is in fact reflective, thus identifying the sensor response as a true glint or an event requiring further analysis.
Date: March 1, 2009
Creator: Nelsen, James M., Jr.; Hohlfelder, Robert James; Jackson, Dale Clayton & Longenbaugh, Randolph S.
Partner: UNT Libraries Government Documents Department
open access

The Future of Remote Sensing From Space: Civilian Satellite Systems and Applications

Description: This report examines issues related to the development and operation of publicly funded U.S. and foreign civilian remote sensing systems. It also explores the military and intelligence use of data gathered by civilian satellites. In addition, the report examines the outlook for privately funded and operated remote sensing systems.
Date: July 1993
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department
open access

Data Format Standards for Civilian Remote Sensing Satellites

Description: This report discusses the earth data—positional, topographic, climatological, meteorological, man–made features, and changes over time in all of these, which are increasingly important to the military. Data from these systems are bought and extensively used by the military and intelligence communities. The need to integrate data from military-unique systems as well only complicates the situation.
Date: May 1993
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department
open access

Final Report of Research Conducted For DE-AI02-08ER64546

Description: Research was conducted for 3-4 years to use ARM data to validate satellite cloud retrievals and help the development of improved techniques for remotely sensing clouds and radiative fluxes from space to complement the ARM surface measurement program. This final report summarizes the results and publications during the last 2 years of the studies. Since our last report covering the 2009 period, we published four papers that were accepted during the previous reporting period and revised and published a fifth one. Our efforts to intercalibrate selected channels on several polar orbiting and geostationary satellite imagers, which are funded in part by ASR, resulted in methods that were accepted as part of the international Global Space-based Intercalibration System (GSICS) calibration algorithms. We developed a new empirical method for correcting the spectral differences between comparable channels on various imagers that will be used to correct the calibrations of the satellite data used for ARM. We documented our cloud retrievals for the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex; ARM participated with an AAF contribution) in context of the entire experiment. We used our VOCALS satellite data along with the aircraft measurements to better understand the relationships between aerosols and liquid water path in marine stratus clouds. We continued or efforts to validate and improve the satellite cloud retrievals for ARM and using ARM data to validate retrievals for other purposes.
Date: March 28, 2012
Creator: Minnis, Patrick
Partner: UNT Libraries Government Documents Department
open access

Improvements in Near-Terminator and Nocturnal Cloud Masks using Satellite Imager Data over the Atmospheric Radiation Measurement Sites

Description: Cloud detection using satellite measurements presents a big challenge near the terminator where the visible (VIS; 0.65 {micro}m) channel becomes less reliable and the reflected solar component of the solar infrared 3.9-{micro}m channel reaches very low signal-to-noise ratio levels. As a result, clouds are underestimated near the terminator and at night over land and ocean in previous Atmospheric Radiation Measurement (ARM) Program cloud retrievals using Geostationary Operational Environmental Satellite (GOES) imager data. Cloud detection near the terminator has always been a challenge. For example, comparisons between the CLAVR-x (Clouds from Advanced Very High Resolution Radiometer [AVHRR]) cloud coverage and Geoscience Laser Altimeter System (GLAS) measurements north of 60{sup o}N indicate significant amounts of missing clouds from AVHRR because this part of the world was near the day/night terminator viewed by AVHRR. Comparisons between MODIS cloud products and GLAS at the same regions also shows the same difficulty in the MODIS cloud retrieval (Pavolonis and Heidinger 2005). Consistent detection of clouds at all times of day is needed to provide reliable cloud and radiation products for ARM and other research efforts involving the modeling of clouds and their interaction with the radiation budget. To minimize inconsistencies between daytime and nighttime retrievals, this paper develops an improved twilight and nighttime cloud mask using GOES-9, 10, and 12 imager data over the ARM sites and the continental United States (CONUS).
Date: March 18, 2005
Creator: Trepte, Q.Z.; Minnis, P.; Heck, P.W. & Palikonda, R.
Partner: UNT Libraries Government Documents Department
open access

Conformal coating value/risk assessment for Sandia satellite programs.

Description: Conformal coatings are used in space applications on printed circuit board (PCB) assemblies primarily as a protective barrier against environmental contaminants. Such coatings have been used at Sandia for decades in satellite applications including the GPS satellite program. Recently, the value of conformal coating has been questioned because it is time consuming (requiring a 5-6 week schedule allowance) and delays due to difficulty of repairs and rework performed afterward are troublesome. In an effort to find opportunities where assembly time can be reduced, a review of the literature as well as discussions with satellite engineers both within and external to Sandia regarding the value of conformal coating was performed. Several sources on the value of conformal coating, the functions it performs, and on whether coatings are necessary and should be used at all were found, though nearly all were based on anecdotal information. The first section of this report, titled 'Conformal Coating for Space Applications', summarizes the results of an initial risk-value assessment of the conformal coating process for Sandia satellite programs based on information gathered. In the process of collecting information to perform the assessment, it was necessary to obtain a comprehensive understanding of the entire satellite box assembly process. A production time-line was constructed and is presented in the second section of this report, titled 'Satellite Box Assembly', specifically to identify potential sources of time delays, manufacturing issues, and component failures related to the conformal coating process in relation to the box assembly. The time-line also allows for identification of production issues that were anecdotally attributed to the conformal coating but actually were associated with other production steps in the box assembly process. It was constructed largely in consultation with GPS program engineers with empirical knowledge of times required to complete the production steps, and who are familiar …
Date: March 1, 2008
Creator: Russick, Edward Mark & Thayer, Gayle Echo
Partner: UNT Libraries Government Documents Department
open access

Global positioning system pseudolite-based relative navigation.

Description: Though the Global Positioning System has revolutionized navigation in the modern age, it is limited in its capability for some applications because an unobstructed line of sight to a minimum of four satellites is required. One way of augmenting the system in small areas is by employing pseudolites to broadcast additional signals that can be used to improve the user's position solution. At the Navigation Systems Testing Laboratory (NSTL) at NASA's Johnson Space Center in Houston, TX, research has been underway on the use of pseudolites to perform precision relative navigation. Based on the findings of previous research done at the NSTL, the method used to process the pseudolite measurements is an extended Kalman filter of the double differenced carrier phase measurements. By employing simulations of the system, as well as processing previously collected data in a real time manner, sub-meter tracking of a moving receiver with carrier phase measurements in the extended Kalman filter appears to be possible.
Date: March 2004
Creator: Monda, Eric W.
Partner: UNT Libraries Government Documents Department
open access

In-situ FPGA debug driven by on-board microcontroller

Description: Often we are faced with the situation that the behavior of a circuit changes in an unpredictable way when chassis cover is attached or the system is not easily accessible. For instance, in a deployed environment, such as space, hardware can malfunction in unpredictable ways. What can a designer do to ascertain the cause of the problem? Register interrogations only go so far, and sometimes the problem being debugged is register transactions themselves, or the problem lies in FPGA programming. This work provides a solution to this; namely, the ability to drive a JTAG chain via an on-board microcontroller and use a simple clone of the Xilinx Chipscope core without a Xilinx JTAG cable or any external interfaces required. We have demonstrated the functionality of the prototype system using a Xilinx Spartan 3E FPGA and a Microchip PIC18j2550 microcontroller. This paper will discuss the implementation details as well as present case studies describing how the tools have aided satellite hardware development.
Date: January 1, 2009
Creator: Baker, Zachary Kent
Partner: UNT Libraries Government Documents Department
open access

Radiation load to the SNAP CCD

Description: Results of an express Monte Carlo analysis with the MARS14 code of radiation load to the CCD optical detectors in the Supernova Acceleration Project (SNAP) mission presented for realistic radiation environment over the satellite orbit.
Date: August 14, 2003
Creator: N. V. Mokhov, I. L. Rakhno and S. I. Striganov
Partner: UNT Libraries Government Documents Department
open access

Testing Impact?s Radiation Code

Description: This is a summary of work done over an 8 week period from May to July 2004, which concerned testing the longwave and shortwave radiation packages in Impact. The radiation code was initially developed primarily by Keith Grant in the context of LLNL's 2D model, and was added to Impact over the last few summers. While the radiation code had been tested and also used in some aerosol-related calculations, its 3D form in Impact had not been validated with comparisons to satellite data. Along with such comparisons, our work described here was also motivated by the need to validate the radiation code for use in the SciDAC consortium project. This involved getting the radiation code working with CAM/WACCM met data, and setting the stage for comparing CAM/WACCM radiation output with Impact results.
Date: July 12, 2004
Creator: Edis, Taner; Cameron-Smith, Philip; Grant, Keith E.; Bergmann, Dan & Chuang, Catherine C.
Partner: UNT Libraries Government Documents Department
open access

Constructing a coherent long-term global total ozone climatology from the BUV, MFR, and SBUV/TOMS data sets

Description: The backscatter ultraviolet spectrometer (BUV) aboard the NIMBUS 4 satellite provided global ozone data until mid-1977. The Total Ozone Mapping Spectrometer (TOMS) and Solar Backscattered Ultraviolet (SBUV) instrument aboard the NIMBUS 7 satellite began providing global ozone in November 1978. The only satellite derived global total ozone data available between the termination of the BUV data and the startup of the SBUV/TOMS data is that from the Multichannel Filter Radiometer (MFR) instrument aboard the Defense Meteorological Satellite Program (DMSP) series of satellites. The MFR and the SBUV/TOMS data are compared during the data overlap period in order to determine how well the MFR data might be used to represent the SBUV/TOMS and BUV data during the data gap period. 5 refs., 3 figs., 3 tabs.
Date: February 1, 1986
Creator: Ellis, J.S. & Luther, F.M.
Partner: UNT Libraries Government Documents Department
open access

The Commercial Space Industry and Launch Market

Description: The report discusses how the space industry is a subset of the U.S. aerospace industry and U.S. strength in aerospace has helped to provide U.S. strength in space. It also points out manufacturing for commercial space and employment in the U.S. Space Industry.
Date: April 20, 2012
Creator: Harrison, Glennon J.
Partner: UNT Libraries Government Documents Department
open access

Bigfoot Field Manual, Version 2.1

Description: The BigFoot Project is funded by the Earth Science Enterprise to collect and organize data to be used in the National Aeronautics and Space Administration's Earth Observing System (EOS) Validation Program. The data collected by the BigFoot Project are unique in being ground-based observations coincident with satellite overpasses. In addition to collecting data, the BigFoot project will develop and test new algorithms for scaling point measurements to the same spatial scales as the EOS satellite products. This BigFoot Field Manual will be used to achieve completeness and consistency of data collected at four initial BigFoot sites and at future sites that may collect similar validation data. Therefore, validation datasets submitted to the Oak Ridge National Laboratory Distributed Active Archive Center that have been compiled in a manner consistent with the field manual will be especially valuable in the validation program.
Date: September 1, 1999
Creator: Campbell, John L.; Burrows, Sean; Gower, Stith Tom & Cohen, Warren B.
Partner: UNT Libraries Government Documents Department
open access

Commercial newsgathering from space

Description: This technical memorandum concludes that although the technology is available to create a mediasat system, the high cost and current low demand for remotely sensed data will limit media efforts to own and operate a dedicated remote sensing satellite system.
Date: May 1987
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department
open access

DEVELOPMENT OF IMPROVED TECHNIQUES FOR SATELLITE REMOTE SENSING OF CLOUDS AND RADIATION USING ARM DATA, FINAL REPORT

Description: During the period, March 1997 – February 2006, the Principal Investigator and his research team co-authored 47 peer-reviewed papers and presented, at least, 138 papers at conferences, meetings, and workshops that were supported either in whole or in part by this agreement. We developed a state-of-the-art satellite cloud processing system that generates cloud properties over the Atmospheric Radiation (ARM) surface sites and surrounding domains in near-real time and outputs the results on the world wide web in image and digital formats. When the products are quality controlled, they are sent to the ARM archive for further dissemination. These products and raw satellite images can be accessed at http://cloudsgate2.larc.nasa.gov/cgi-bin/site/showdoc?docid=4&cmd=field-experiment-homepage&exp=ARM and are used by many in the ARM science community. The algorithms used in this system to generate cloud properties were validated and improved by the research conducted under this agreement. The team supported, at least, 11 ARM-related or supported field experiments by providing near-real time satellite imagery, cloud products, model results, and interactive analyses for mission planning, execution, and post-experiment scientific analyses. Comparisons of cloud properties derived from satellite, aircraft, and surface measurements were used to evaluate uncertainties in the cloud properties. Multiple-angle satellite retrievals were used to determine the influence of cloud structural and microphysical properties on the exiting radiation field.
Date: June 28, 2013
Creator: Minnis, Patrick
Partner: UNT Libraries Government Documents Department
open access

Nuclear vs Solar Power for Earth-Orbit Missions, August 26-30, 1974

Description: The anticipated development of advanced nuclear-radioisotope power systems has led to a reevaluation of their possible utility in earth-orbit missions of various kinds. Because such missions almost always have the option of using solar-power, a decision for nuclear power will have to be based on clear economic grounds, in most cases. However, the economic evaluation must be based on overall system factors, not on power-system cost comparisons alone. On this basis, the advanced nuclear systems can be justified for many operational missions. Examples to be discussed include synchronous-orbit commercial communications satellites and inclined-orbit navigation satellites. There is a duplicate copy
Date: January 1, 1974
Creator: Raab, Bernard & Karlin, Jay J.
Partner: UNT Libraries Government Documents Department
open access

Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal

Description: This report discusses the National Security Space Strategy. After decades of activities in space, Earth's orbit is littered with man-made objects that no longer serve a useful purpose that potentially threaten U.S. national security interests in space, both governmental (military, intelligence, and civil) and commercial. Congress has broadly supported the full-range of these national security interests and has a vested concern in ensuring a strong and continued U.S. presence in space.
Date: January 8, 2014
Creator: Hildreth, Steven A. & Arnold, Allison
Partner: UNT Libraries Government Documents Department
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