Mr. Robert J. DeCoursey Profile

Robert J. DeCoursey

at NASA Langley Research Ctr

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Author

Publications (6)

Proceedings Article | 3 October 2006 Paper

Non-radiation hardened microprocessors in space-based remote sensing systems

R. DeCoursey, Ryan Melton, Robert Estes

Proceedings Volume 6361, 63611M (2006) https://doi.org/10.1117/12.687048

KEYWORDS: Remote sensing, Sensing systems, LIDAR, Space operations, Satellites, Data acquisition, Computing systems, Infrared cameras, Infrared imaging, Infrared radiation

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The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is a comprehensive suite of active and passive sensors including a 20Hz 230mj Nd:YAG lidar, a visible wavelength Earth-looking camera and an imaging infrared radiometer. CALIPSO flies in formation with the Earth Observing System Post-Meridian (EOS PM) train, provides continuous, near-simultaneous measurements and is a planned 3 year mission. CALIPSO was launched into a 98 degree sun synchronous Earth orbit in April of 2006 to study clouds and aerosols and acquires over 5 gigabytes of data every 24 hours. Figure 1 shows the ground track of one CALIPSO orbit as well as high and low intensity South Atlantic Anomaly outlines. CALIPSO passes through the SAA several times each day. Spaced based remote sensing systems that include multiple instruments and/or instruments such as lidar generate large volumes of data and require robust real-time hardware and software mechanisms and high throughput processors. Due to onboard storage restrictions and telemetry downlink limitations these systems must pre-process and reduce the data before sending it to the ground. This onboard processing and realtime requirement load may mean that newer more powerful processors are needed even though acceptable radiation-hardened versions have not yet been released. CALIPSO's single board computer payload controller processor is actually a set of four (4) voting non-radiation hardened COTS Power PC 603r's built on a single width VME card by General Dynamics Advanced Information Systems (GDAIS). Significant radiation concerns for CALIPSO and other Low Earth Orbit (LEO) satellites include the South Atlantic Anomaly (SAA), the north and south poles and strong solar events. Over much of South America and extending into the South Atlantic Ocean (see figure 1) the Van Allen radiation belts dip to just 200-800km and spacecraft entering this area are subjected to high energy protons and experience higher than normal Single Event Upset (SEU) and Single Event Latch-up (SEL) rates. Although less significant, spacecraft flying in the area around the poles experience similar upsets. Finally, powerful solar proton events in the range of 10MeV/10pfu to 100MeV/1pfu as are forecasted and tracked by NOAA's Space Environment Center in Colorado can result in SingleEvent Upset (SEU), Single Event Latch-up (SEL) and permanent failures such as Single Event Gate Rupture (SEGR) in some technologies. (Galactic Cosmic Rays (GCRs) are another source, especially for gate rupture) CALIPSO mitigates common radiation concerns in its data handling through the use of redundant processors, radiation-hardened Application Specific Integrated Circuits (ASIC), hardware-based Error Detection and Correction (EDAC), processor and memory scrubbing, redundant boot code and mirrored files. After presenting a system overview this paper will expand on each of these strategies. Where applicable, related on-orbit data collected since the CALIPSO initial boot on May 4, 2006 will be noted.

Proceedings Article | 12 January 2005 Paper

CALIPSO space based aerosol lidar: flight software design and planned operations paradigm

Robert DeCoursey, William Hunt, Sudha Natarajan, Ron Verhappen, Mary Beth Wusk, Patricia Lucker

Proceedings Volume 5653, (2005) https://doi.org/10.1117/12.578905

KEYWORDS: LIDAR, Control systems, Space operations, Satellites, Data acquisition, Data centers, Transmitters, Aerosols, Receivers, Clocks

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Proceedings Article | 6 August 1997 Paper

Aircraft exhaust particle measurement with multiple ground-based lidar systems

Robert DeCoursey, Lamont Poole, Chris Hostetler, Geoffrey Kent, Gary Hansen

Proceedings Volume 3065, (1997) https://doi.org/10.1117/12.281005

KEYWORDS: LIDAR, Transmitters, Data acquisition, Atmospheric particles, Aerosols, Data modeling, Receivers, Fluid dynamics, Particles, Radar

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Proceedings Article | 26 June 1996 Paper

Long-term observations of the midlatitude stratospheric aerosol from the Mount Pinatubo eruption

David Woods, David Winker, Otto Youngbluth, Mary Osborn, Robert DeCoursey

Proceedings Volume 2748, (1996) https://doi.org/10.1117/12.243566

KEYWORDS: Aerosols, Backscatter, LIDAR, Clouds, Atmospheric particles, Stratosphere, Nd:YAG lasers, Atmospheric sciences, Sensors, Sun

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Proceedings Article | 26 June 1996 Paper

Recent modifications, enhancements, and measurements with an airborne lidar system

Robert DeCoursey, Mary Osborn, David Winker, David Woods

Proceedings Volume 2748, (1996) https://doi.org/10.1117/12.243576

KEYWORDS: LIDAR, Aerosols, Sensors, Computing systems, Global Positioning System, Receivers, Telescopes, Signal detection, Signal processing, Data acquisition

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Proceedings Article | 15 October 1993 Paper

Recent modifications and measurements with a ground-based lidar system

David Woods, David Winker, Otto Youngbluth, Mary Osborn, Robert DeCoursey

Proceedings Volume 1936, (1993) https://doi.org/10.1117/12.157105

KEYWORDS: LIDAR, Aerosols, Backscatter, Scattering, Sensors, Atmospheric particles, Clouds, Laser applications, Laser scattering, Nd:YAG lasers

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Showing 5 of 6 publications

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