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  • 1
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    Ground clutter measurements using the NASA airborne doppler radar: Description of clutter at the Denver and Philadelphia airports (1992)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Detection of hazardous wind shears from an airborne platform, using commercial sized radar hardware, has been debated and researched for several years. The primary concern has been the requirement for 'look-down' capability in a Doppler radar during the approach and landing phases of flight. During 'look-down' operation, the received signal (weather signature) will be corrupted by ground clutter returns. Ground clutter at and around urban airports can have large values of Normalized Radar Cross Section (NRCS) producing clutter returns which could saturate the radar's receiver, thus disabling the radar entirely, or at least from its intended function. The purpose of this research was to investigate the NRCS levels in an airport environment (scene), and to characterize the NRCS distribution across a variety of radar parameters. These results are also compared to results of a similar study using Synthetic Aperture Radar (SAR) images of the same scenes. This was necessary in order to quantify and characterize the differences and similarities between results derived from the real-aperature system flown on the NASA 737 aircraft and parametric studies which have previously been performed using the NASA airborne radar simulation program.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: Airborne Wind Shear Detection and Warning Systems: Fourth Combined Manufacturers' and Technologists' Conference, Part 1; p 499-516
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Clutter modeling of the Denver Airport and surrounding areas (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: To accurately simulate and evaluate an airborne Doppler radar as a wind shear detection and avoidance sensor, the ground clutter surrounding a typical airport must be quantified. To do this, an imaging airborne Synthetic Aperture Radar (SAR) was employed to investigate and map the normalized radar cross sections (NRCS) of the ground terrain surrounding the Denver Stapleton Airport during November of 1988. Images of the Stapleton ground clutter scene were obtained at a variety of aspect and elevation angles (extending to near-grazing) at both HH and VV polarizations. Presented here, in viewgraph form with commentary, are the method of data collection, the specific observations obtained of the Denver area, a summary of the quantitative analysis performed on the SAR images to date, and the statistical modeling of several of the more interesting stationary targets in the SAR database. Additionally, the accompanying moving target database, containing NRCS and velocity information, is described.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: NASA. Langley Research Center, Airborne Wind Shear Detection and Warning Systems: Third Combined Manufacturers' and Technologists' Conference, Part 2; p 783-836
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Aspects of Synthetic Vision Display Systems and the Best Practices of the NASA's SVS Project (2008)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: NASA s Synthetic Vision Systems (SVS) Project conducted research aimed at eliminating visibility-induced errors and low visibility conditions as causal factors in civil aircraft accidents while enabling the operational benefits of clear day flight operations regardless of actual outside visibility. SVS takes advantage of many enabling technologies to achieve this capability including, for example, the Global Positioning System (GPS), data links, radar, imaging sensors, geospatial databases, advanced display media and three dimensional video graphics processors. Integration of these technologies to achieve the SVS concept provides pilots with high-integrity information that improves situational awareness with respect to terrain, obstacles, traffic, and flight path. This paper attempts to emphasize the system aspects of SVS - true systems, rather than just terrain on a flight display - and to document from an historical viewpoint many of the best practices that evolved during the SVS Project from the perspective of some of the NASA researchers most heavily involved in its execution. The Integrated SVS Concepts are envisagements of what production-grade Synthetic Vision systems might, or perhaps should, be in order to provide the desired functional capabilities that eliminate low visibility as a causal factor to accidents and enable clear-day operational benefits regardless of visibility conditions.
    Keywords: Air Transportation and Safety
    Type: NASA/TP-2008-215130 , L-19422
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns (2019)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: NASA and the FAA conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding and develop onboard weather radar processing to detect regions of high ice water content ahead of an aircraft and enable tactical avoidance of the potentially hazardous conditions. Both High Ice Water Content (HIWC) RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory which was equipped with a Honeywell RDR-4000 weather radar and icing instruments to characterize the ice crystals clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results.
    Keywords: Meteorology and Climatology
    Type: GRC-E-DAA-TN69115 , SAE International Conference on Icing of Aircraft, Engines, and Structures; Jun 17, 2019 - Jun 21, 2019; Minneapolis, MN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Real-Time Integrity Monitoring of Stored Geo-Spatial Data Using Forward-Looking Remote Sensing Technology (2002)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Terrain Awareness and Warning Systems (TAWS) and Synthetic Vision Systems (SVS) provide pilots with displays of stored geo-spatial data (e.g. terrain, obstacles, and/or features). As comprehensive validation is impractical, these databases typically have no quantifiable level of integrity. This lack of a quantifiable integrity level is one of the constraints that has limited certification and operational approval of TAWS/SVS to "advisory-only" systems for civil aviation. Previous work demonstrated the feasibility of using a real-time monitor to bound database integrity by using downward-looking remote sensing technology (i.e. radar altimeters). This paper describes an extension of the integrity monitor concept to include a forward-looking sensor to cover additional classes of terrain database faults and to reduce the exposure time associated with integrity threats. An operational concept is presented that combines established feature extraction techniques with a statistical assessment of similarity measures between the sensed and stored features using principles from classical detection theory. Finally, an implementation is presented that uses existing commercial-off-the-shelf weather radar sensor technology.
    Keywords: Avionics and Aircraft Instrumentation
    Type: 21st Digital Avionics Systems Conference; Oct 28, 2002 - Oct 31, 2002; Irvine, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Initial SVS Integrated Technology Evaluation Flight Test Requirements and Hardware Architecture (2003)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: This document presents the flight test requirements for the Initial Synthetic Vision Systems Integrated Technology Evaluation flight Test to be flown aboard NASA Langley's ARIES aircraft and the final hardware architecture implemented to meet these requirements. Part I of this document contains the hardware, software, simulator, and flight operations requirements for this light test as they were defined in August 2002. The contents of this section are the actual requirements document that was signed for this flight test. Part II of this document contains information pertaining to the hardware architecture that was realized to meet these requirements as presented to and approved by a Critical Design Review Panel prior to installation on the B-757 Airborne Research Integrated Experiments Systems (ARIES) airplane. This information includes a description of the equipment, block diagrams of the architecture, layouts of the workstations, and pictures of the actual installations.
    Keywords: Instrumentation and Photography
    Type: NASA/TM-2003-212644 , L-18325 , NAS 1.15:212644
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Real-time Enhanced Vision System (2005)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Flying in poor visibility conditions, such as rain, snow, fog or haze, is inherently dangerous. However these conditions can occur at nearly any location, so inevitably pilots must successfully navigate through them. At NASA Langley Research Center (LaRC), under support of the Aviation Safety and Security Program Office and the Systems Engineering Directorate, we are developing an Enhanced Vision System (EVS) that combines image enhancement and synthetic vision elements to assist pilots flying through adverse weather conditions. This system uses a combination of forward-looking infrared and visible sensors for data acquisition. A core function of the system is to enhance and fuse the sensor data in order to increase the information content and quality of the captured imagery. These operations must be performed in real-time for the pilot to use while flying. For image enhancement, we are using the LaRC patented Retinex algorithm since it performs exceptionally well for improving low-contrast range imagery typically seen during poor visibility conditions. In general, real-time operation of the Retinex requires specialized hardware. To date, we have successfully implemented a single-sensor real-time version of the Retinex on several different Digital Signal Processor (DSP) platforms. In this paper we give an overview of the EVS and its performance requirements for real-time enhancement and fusion and we discuss our current real-time Retinex implementations on DSPs.
    Keywords: Aircraft Communications and Navigation
    Type: SPIE-5802-11 , SPIE Defense and Security Symposium 2005; Mar 28, 2005 - Apr 01, 2005; Orlando, FL; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
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    Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA and the FAA (Federal Aviation Administration) conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding and develop onboard weather radar processing to detect regions of high ice water content ahead of an aircraft and enable tactical avoidance of the potentially hazardous conditions. Both High Ice Water Content (HIWC) RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory which was equipped with a Honeywell RDR-4000 weather radar and icing instruments to characterize the ice crystal clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results.
    Keywords: Meteorology and Climatology
    Type: GRC-E-DAA-TN66897 , International Conference on Icing of Aircraft, Engines, and Structures; Jun 17, 2019 - Jun 21, 2019; Minneapolis, MN; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
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