ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Coherent laser radar at 2 microns using solid-state lasers (1993)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Coherent laser radar systems using 2-micron Tm- and Tm, Ho-doped solid-state lasers are useful for the remote range-resolved measurement of atmospheric winds, aerosol backscatter, and DIAL measurements of atmospheric water vapor and CO2 concentrations. Recent measurements made with a 2-micron coherent laser radar system, advances in the laser technology, and atmospheric propagation effects on 2-micron coherent lidar performance are described.
    Keywords: LASERS AND MASERS
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 31; 1; p. 4-15.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    High-Efficiency Autonomous Coherent Lidar (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: A useful measure of sensor performance is the transceiver system efficiency n (sub sys). Which consists of the antenna efficiency n (sub a) and optical and electronic losses. Typically, the lidar equation and the antenna efficiency are defined in terms of the telescope aperture area. However, during the assembly of a coherent transceiver, it is important to measure the system efficiency before the installation of the beamexpanding telescope (i.e., the untruncated-beam system efficiency). Therefore, to accommodate both truncated and untruncated beam efficiency measurements, we define the lidar equation and the antenna efficiency in terms of the beam area rather than the commonly used aperture area referenced definition. With a well-designed Gaussian-beam lidar, aperture area referenced system efficiencies of 15 to 20 % (23-31% relative to the beam area) are readily achievable. In this paper we compare the differences between these efficiency definitions. We then describe techniques by which high efficiency can be achieved, followed by a discussion several novel auto alignment techniques developed to maintain high efficiency.
    Keywords: Instrumentation and Photography
    Type: Tenth Biennial Coherent Laser Radar Technology and Applications Conference; 247-250; NASA/CP-1999-209758
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Wake vortex detection at Denver Stapleton Airport with a pulsed 2-micron coherent lidar (1994)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: This report describes the effort undertaken to relate aircraft wake history to the local environment. This involved the monitoring of the embedded windfield, monitoring of local meteorological parameters, a high-resolution velocity field analysis in vertical scan planes and measurement of the axial velocity signature. A flashlight pumped 2.09 micron solid state coherent laser radar system was used to detect and track wake vortices. Strong wake vortex signatures were measured for moderate to large aircraft at Denver's Stapleton airport and a large vortex database was compiled.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: NASA. Langley Research Center, Airborne Windshear Detection and Warning Systems. Fifth and Final Combined Manufacturers' and Technologists' Conference, Part 2; p 625-650
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Airport surveillance using a solid state coherent lidar (1994)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: The utility of solid state coherent LIDAR was assessed in the following application areas: (1) wake vortices; (2) dry and wet microburst windshear; (3) gusts; (4) vertical and general wind profiling; and (5) cloud ceiling. The system performance model described was based on a concept definition, system sizing, measurement planning, and algorithm and graphics display development. Data were collected at the Kennedy Space Center and the National Weather Service site adjacent to Denver's Stapleton Airport.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: NASA. Langley Research Center, Airborne Windshear Detection and Warning Systems. Fifth and Final Combined Manufacturers' and Technologists' Conference, Part 2; p 499-523
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Performance of a 2-micrometer coherent Doppler lidar for wind measurements (1994)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Measurements of boundary layer winds are presented using a 2-micrometer coherent Doppler lidar and the optimal performance of the maximum likelihood estimator. The systematic error for single-shot estimates was estimated as 3.6 cm/s using measurements from a stationary hard target. The estimation error for measurements of the radial component of the wind field was determined, as well as the fraction of the estimates that are randomly distributed over the velocity search space, when the signal power is low and speckle fading is important. The results from actual data are compared with the results from ideal simulations. The first direct estimation of the spatial structure function of the radial wind field and of the energy dissipation rate is presented for both horizontal and vertical directions of propagation. The rms estimation error of the velocity estimates is found to be within 30% of ideal performance based on simulation.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 11; 6; p. 1517-1528
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) Flight Testing of the Lidar Sensor (2000)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The purpose of the ACLAIM program is ultimately to establish the viability of light detection and ranging (lidar) as a forward-looking sensor for turbulence. The goals of this flight test are to: 1) demonstrate that the ACLAIM lidar system operates reliably in a flight test environment, 2) measure the performance of the lidar as a function of the aerosol backscatter coefficient (beta), 3) use the lidar system to measure atmospheric turbulence and compare these measurements to onboard gust measurements, and 4) make measurements of the aerosol backscatter coefficient, its probability distribution and spatial distribution. The scope of this paper is to briefly describe the ACLAIM system and present examples of ACLAIM operation in flight, including comparisons with independent measurements of wind gusts, gust-induced normal acceleration, and the derived eddy dissipation rate.
    Keywords: Instrumentation and Photography
    Type: H-2428 , Aviation, Range and Aerospace Meteorology; Sep 11, 2000 - Sep 15, 2000; Orlando, FL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Juneau Airport Doppler Lidar Deployment: Extraction of Accurate Turbulent Wind Statistics (1999)
    In:  CASI
    Details
    Publication Date: 2019-08-16
    Description: A 2 micrometer pulsed Doppler lidar was deployed to the Juneau Airport in 1998 to measure turbulence and wind shear in and around the departure and arrival corridors. The primary objective of the measurement program was to demonstrate and evaluate the capability of a pulsed coherent lidar to remotely and unambiguously measure wind turbulence. Lidar measurements were coordinated with flights of an instrumented research aircraft operated by representatives of the University of North Dakota (UND) under the direction of the National Center for Atmospheric Research (NCAR). The data collected is expected to aid both turbulence characterization as well as airborne turbulence detection algorithm development activities within NASA and the FAA. This paper presents a summary of the deployment and results of analysis and simulation which address important issues regarding the measurement requirements for accurate turbulent wind statistics extraction.
    Keywords: Meteorology and Climatology
    Type: Tenth Biennial Coherent Laser Radar Technology and Applications Conference; 24-27; NASA/CP-1999-209758
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Airborne Turbulence Detection and Warning ACLAIM Flight Test Results (1999)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: The Airborne Coherent Lidar for Advanced Inflight Measurements (ACLAIM) is a NASA/Dryden-lead program to develop and demonstrate a 2 micrometers pulsed Doppler lidar for airborne look-ahead turbulence detection and warning. Advanced warning of approaching turbulence can significantly reduce injuries to passengers and crew aboard commercial airliners. The ACLAIM instrument is a key asset to the ongoing Turbulence component of NASA's Aviation Safety Program, aimed at reducing the accident rate aboard commercial airliners by a factor of five over the next ten years and by a factor of ten over the next twenty years. As well, the advanced turbulence warning capability can prevent "unstarts" in the inlet of supersonic aircraft engines by alerting the flight control computer which then adjusts the engine to operate in a less fuel efficient, and more turbulence tolerant, mode. Initial flight tests of the ACLAIM were completed in March and April of 1998. This paper and presentation gives results from these initial flights, with validated demonstration of Doppler lidar wind turbulence detection several kilometers ahead of the aircraft.
    Keywords: Meteorology and Climatology
    Type: Tenth Biennial Coherent Laser Radar Technology and Applications Conference; 20-23; NASA/CP-1999-209758
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Comparison of Predicted and Measured 2 Micron Aerosol Backscatter from the 1998 ACLAIM Flight Tests (1999)
    In:  Other Sources
    Details
    Publication Date: 2019-07-17
    Description: The 1998 Airborne Coherent Lidar for Advanced Inflight Measurements (ACLAIM) flight tests were conducted aboard a well-instrumented research aircraft. This paper presents comparisons of 2 micrometer aerosol backscatter coefficient predictions from aerosol sampling data and mie scattering codes with those produced by the ACLAIM instrument.
    Keywords: Instrumentation and Photography
    Type: Tenth Biennial Coherent Laser Radar Technology and Applications Conference; 151; NASA/CP-1999-209758
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...