DOCSLIB.ORG

Optical Turbulence Profiling at White Sands Missile Range North Oscura Peak

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Optical Turbulence Profiling at White Sands Missile Range North Oscura Peak MZA Associates Corporation Optical turbulence profiling at White Sands Missile Range North Oscura Peak Dr. Matthew R. Whiteley, Rebecca L. Beauchamp, and Jonathan Diemunsch (MZA) Dr. Richard J. Bagnell Air Force Research Laboratory, Starfire Optical Range November 2, 2006 MZA Associates Corporation 6651 Centerville Business Pkwy Ste B Dayton, OH 45459-2678 CLEARED FOR PUBLIC RELEASE Voice: (937) 432-6560 x237 AFRL/DEO-PA, 31 OCT 06 1 MRW – 11/2/2006 Introduction MZA Associates Corporation z AFRL Starfire Optical Range owns/operates a device known as the “Differential-Tilt Turbulence Profiler” z Development timeline 2000: AFRL/DE and AFOSR developed original concept, theory, initial design 2001-2003: AFRL/DE and MZA integrated the laser & optical system, developed data acquisition software 2002-2005: AFRL/DE conducted simulations, developed processing algorithms, initial testing and data analysis 2006: Full-scale system test at North Oscura Peak (NOP) z Testing timeline 2003: NOP to Bug (~1 km), NOP to Beck (~10 km) Initial data, but issue with source assembly 2004: SOR to 2-mile (~3 km) Revised source assembly Reasonable test data and profiling results for 3 km path 2005: NOP to Salinas (~50 km) Poor SNR limited measurements, profiling questionable 2006: NOP to Beck (~10 km) Good SNR, reasonable profiles, large data volume, other diagnostics 2 MRW – 11/2/2006 Differential-Tilt Turbulence Profiler MZA Associates Corporation atmospheric turbulence Telescope Telescope and source and source assembly assembly data data acquisition acquisition 0 normalized path position 1 3 MRW – 11/2/2006 Estimation of Coherence Diameter from MZA Associates Corporation Profiler Centroid Data z Can use centroid (tilt) data directly from profiler units with standard techniques for r0 estimation Estimation from tilt-variance: Differential-tilt variance for 3 aperture pairs on each unit z Ap-1 / Ap-2 with s/D = 1.5875 Æ z Ap-3 / Ap-4 with s/D = 6.9850 Æ z Ap-5 / Ap-6 with s/D = 1.5875 Æ 4 MRW – 11/2/2006 Profiler Theory of Operation MZA Associates Corporation z Profiler theory published in SPIE proceedings Whiteley, M. R., Washburn, D. C., and Wright, L. A., “Differential-tilt technique for saturation-resistant profiling of atmospheric turbulence,” SPIE Proceedings on Adaptive Optical Systems Technology II 4494, (2001). z Difference of differential-tilt variances define measurement set that can be related to turbulence distribution over path z Relation can be inverted through appropriate numerical technique z Constraints can be applied to inversion using r0 estimates for profiler used as differential-image-motion monitor 5 MRW – 11/2/2006 Wave-Optics Simulation of MZA Associates Corporation Turbulence Profiling WaveTrain System Model 2 2 -15 Profile 2: C relative error = 0.059811 -15 Profile 3: C relative error = 0.10901 x 10 n x 10 n 8 8 reconstructed from data reconstructed from data input to simulation input to simulation 7 7 6 6 5 5 ) ) -2/3 4 -2/3 4 (m (m 2 n 2 n C C 3 3 2 2 1 1 0 0 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 normalized bin position normalized bin position 2 2 2 -15 Profile 4: C relative error = 0.080568 -15 Profile 5: C relative error = 0.16081 -15 Profile 6: C relative error = 0.23198 x 10 n x 10 n x 10 n 8 8 8 reconstructed from data reconstructed from data reconstructed from data input to simulation input to simulation input to simulation 7 7 7 6 6 6 5 5 5 ) ) ) -2/3 -2/3 4 -2/3 4 4 (m (m (m 2 n 2 n 2 n C C C 3 3 3 2 2 2 1 1 1 0 0 0 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 normalized bin position normalized bin position normalized bin position 6 MRW – 11/2/2006 NOP-to-Beck Site Data Collection MZA Associates Corporation z Turbulence profiler data was collected on NOP-to-Beck path 9.6 km, ~900 m altitude change April-August 2006 Other data items Scintillometer km 9.6 Tactical imagery z 33 test days with profiler 7,900 ft z 21 days of good +958 ft +1,512 ft (2,409 ,m) quality/volume for (+292 m) (+461 m) profiling z ~4500 data files z 726 profiles 5,900 ft 0000-0600: 120 5,300 ft (1,799 m) 0600-1200: 86 (1,616 m) 5,015 ft 1200-1800: 110 (1,529 m) 1800-2400: 410 7 MRW – 11/2/2006 Data Quality Checking MZA Associates Corporation APC2006144003600.mat Example of Clipping, Frame 74 z Data filtering implemented to reduce noise 30 sources in differential-tilt estimation 20 25 z Spot SNR 40 Average pixel SNR > 2 for all subapertures 20 z Saturated spot image 60 15 No saturated pixels used in centroid 80 z Spot clipping 10 clipping Subaperture spot too close to centroid 100 processing boundary 5 120 0 z Telescope jitter 20 40 60 80 100 120 Clipping Indicated by Green Circle Quantified by averaging shift over all APC2006144003600. mat 8 subapertures Gross Row Tilt Gross Column Tilt Retained data with jitter std < 7 pixels 6 z Required following attributes for profile 4 processing 2 At least 10% of frames in a file must pass all quality checks 0 Gross Tilt(pixels) At least 200 frames total passing quality checks -2 z SNR was most common reason for data -4 telescope jitter filtering -6 Especially when scintillation was high -8 0 100 200 300 400 500 600 700 800 900 1000 Frame No. 8 MRW – 11/2/2006 Profiling Example: Day 172 MZA Associates Corporation 2 2 1 3 Beck NOP 3 1 Beck NOP Beck NOP 9 MRW – 11/2/2006 Comparison with Scintillometer MZA Associates Corporation z Rytov number from turbulence profiles compared with scintillometer estimate of Rytov number (when available) z It can be shown that for any turbulence profile, the following inequality applies: z A good “rule of thumb” approximation is: z When scintillometer is in bounds implied by profiler, scintillometer and profiler give consistent Rytov number estimates 10 MRW – 11/2/2006 Comparison with Standard MZA Associates Corporation Turbulence Models “Night” 20:00-06:00 “Morning” 06:00-12:00 “Afternoon” 12:00-20:00 11 MRW – 11/2/2006 Conclusions MZA Associates Corporation z Differential-tilt turbulence profiler successfully taken from concept to development and into application ~10 km path from North Oscura Peak to valley floor at WSMR z Substantial test data has been collected and analyzed Filtering for data quality important to assuring turbulence estimate Profile estimates available around the clock Profiles and derived atmospheric propagation parameters consistent with expected trends z Profile estimates validated using independent measurements Consistency between profile Rytov and scintillometer z Diurnal trends (median conditions) Compare favorably to CLEAR-1 model given propagation height above ground Night < 0.5 x CLEAR-1/Night Morning 0.5 – 1.0 x CLEAR-1/Night Afternoon End-points (near ground) 2.0 – 4.0 x CLEAR-1/Night Otherwise, 0.5 – 1.0 x CLEAR-1/Night 12 MRW – 11/2/2006.
Load more

Recommended publications
  • Sodium Guidestar Radiometry Results from the SOR's 50W Fasor
    Sodium Guidestar Radiometry Results from the SOR's 50W Fasor Jack Drummond, Steve Novotny, Craig Denman, Paul Hillman, John Telle, Gerald Moore Starfire Optical Range, Directed Energy Directorate, Air Force Research Laboratory Kirtland AFB, New Mexico 87117-5776 USA Mark Eickhoff Boeing LTS, The Boeing Company, PO Box 5670, Kirtland AFB, New Mexico 87185 USA Robert Fugate New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, New Mexico 87801 USA ABSTRACT Having replaced our 20 W, 589 nm fasor (frequency-addition source of optical radiation) with a new fully computer automated 50 W fasor mounted to the azimuthal base of the 3.5m telescope, we have since produced a sodium laser guidestar (LGS) with a V1 magnitude of 5.1 for 30 W of fasor power in November 2005, when the annual peak in mesospheric sodium density occurs. This corresponds to a return flux at the top of the telescope of 7000 photons/s/cm2 through one airmass. Late in May 2006, however, a return of only 1340 ph/s/cm2 (V1=6.7) for 30 W of fasor power was obtained at the annual minimum in sodium column density. Earlier in the month, with 49 W of fasor power, the LGS was only as bright as V1=6.3 because of the minimum in column density. By measuring the LGS return flux in circular polarization from various altitudes and azimuths, we have detected the presence of the Earth's magnetic field, for the first time ever, as an enhancement in flux from the direction where the field lines are pointing at the SOR.
    [Show full text]
  • Optimization of Cw Sodium Laser Guide Star Efficiency
    A&A 510, A20 (2010) Astronomy DOI: 10.1051/0004-6361/200913108 & c ESO 2010 Astrophysics Optimization of cw sodium laser guide star efficiency R. Holzlöhner1, S. M. Rochester2, D. Bonaccini Calia1,D.Budker2,J.M.Higbie3, and W. Hackenberg1 1 Laser Systems Department, European Southern Observatory (ESO), Karl-Schwarzschild-Str. 2, 85748 Garching b. München, Germany, http://www.eso.org/sci/facilities/develop/lgsf/ e-mail: [rholzloe;dbonacci;whackenb]@eso.org 2 University of California Berkeley, Department of Physics, Berkeley, CA 94720-7300, USA e-mail: [simonr;budker]@berkeley.edu 3 Bucknell University, Department of Physics, 701 Moore Avenue, Lewisburg, PA 17837, USA e-mail: [email protected] Received 12 August 2009 / Accepted 1 October 2009 ABSTRACT Context. Sodium laser guide stars (LGS) are about to enter a new range of laser powers. Previous theoretical and numerical methods are inadequate for accurate computations of the return flux, hence for the design of the next-generation LGS systems. Aims. We numerically optimize the cw (continuous wave) laser format, in particular, the light polarization and spectrum. Methods. Using Bloch equations, we simulate the mesospheric sodium atoms, including Doppler broadening, saturation, collisional relaxation, Larmor precession, and recoil, taking all 24 sodium hyperfine states into account and 100–300 velocity groups. Results. LGS return flux is limited by “three evils”: Larmor precession due to the geomagnetic field, atomic recoil due to radiation pressure, and transition saturation. We study their impact and show that the return flux can be boosted by repumping (simultaneous excitation of the sodium D2aandD2b lines with 10−20% of the laser power in the latter).
    [Show full text]
  • Four Generations of Sodium Guide Star Lasers for Adaptive Optics in Astronomy and Space Situational Awareness
    From Dye Laser Factory to Portable Semiconductor Laser: Four Generations of Sodium Guide Star Lasers for Adaptive Optics in Astronomy and Space Situational Awareness Céline d’Orgeville Advanced Instrumentation and Technology Centre, Research School of Astronomy and Astrophysics, Australian National University; Space Environment Research Centre, Canberra, Australia Gregory J. Fetzer Areté Associates, Longmont, Colorado, USA ABSTRACT This paper recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analyzing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980s and 1990s. These experimental systems were turned into the first laser guide star facilities to equip medium- to-large diameter adaptive optics telescopes, opening a new era of Laser Guide Star Adaptive Optics (LGS AO)- enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000s that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8 to 10m-class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date.
    [Show full text]
  • Factsheets : Starfire Optical Range at Kirtland Air Force Base, New
    Factsheets : Starfire Optical Range at Kirtland Air Force Base,... http://www.kirtland.af.mil/library/factsheets/factsheet.asp?id=15868 HOME NEWS PHOTOS ART LIBRARY UNITS ENVIRONMENT QUESTIONS JOIN THE AIR FORCE Library > Fact sheets > Starfire Optical Range at Kirtland Air Force Base, New Mexico Inside Kirtland AFB STARFIRE OPTICAL RANGE AT KIRTLAND AIR Search FORCE BASE, NEW MEXICO search Kirtland Posted 3/9/2012 Printable Fact Sheet View All RSS Freedom to maneuver in space is critical to meeting the United States Air Force's mission to fly, fight, and win in air, space and cyberspace. The ability to exploit the characteristics of space gives the warfighter a competitive edge in virtually all engagements. Organizations Additionally, space allows the United States to watch the entire globe on an almost "real time" basis, getting instantaneous information. To maintain space situational awareness, the Air Force conducts research in laser guide star adaptive optics, beam control, and space object identification. As satellites get smaller and the number of space objects increases dramatically, research in imaging and identification of space objects is paramount to meeting the Air Force's mission. This facility leads the industry changing technology of laser beacon adaptive optics for military uses and civilian applications such as astronomy. It is a major component of the Air Force Research Laboratory's Directed Energy Directorate. The SOR operates one of the world's premier adaptive-optics telescopes capable of tracking low-earth orbiting satellites. The telescope has a 3.5-meter (11.5 feet) diameter primary mirror and is protected by a retracting cylindrical enclosure that allows the telescope to operate in the open air.
    [Show full text]
  • IAC), Adelaide, Australia, 25-29 September 2017
    68th International Astronautical Congress (IAC), Adelaide, Australia, 25-29 September 2017. Copyright ©2017 by the International Astronautical Federation (IAF). All rights reserved. One or more authors of this work are employees of the government of United States, which may preclude the work from being subject to copyright in United States, in which event no copyright is asserted in that country.” IAC-17-D4.4.5 Earth to Orbit Beamed Energy Experiment Les Johnsona* and Edward E. Montgomeryb a Science and Technology Office, NASA George C. Marshall Space Flight Center, Mail Code ST03, Huntsville, Alabama 35812, [email protected] b Nexolve/Jacobs, Huntsville, AL 35812 * Corresponding Author Abstract As a means of primary propulsion, beamed energy propulsion offers the benefit of offloading much of the propulsion system mass from the vehicle, increasing its potential performance and freeing it from the constraints of the rocket equation. For interstellar missions, beamed energy propulsion is arguably the most viable in the near- to mid-term. A near-term demonstration showing the feasibility of beamed energy propulsion is necessary and, fortunately, feasible using existing technologies. Key enabling technologies are large area, low mass spacecraft and efficient and safe high power laser systems capable of long distance propagation. NASA is currently developing the spacecraft technology through the Near Earth Asteroid Scout solar sail mission and has signed agreements with the Planetary Society to study the feasibility of precursor laser propulsion experiments using their LightSail-2 solar sail spacecraft. The capabilities of Space Situational Awareness assets and the advanced analytical tools available for fine resolution orbit determination now make it possible to investigate the practicalities of an Earth-to-orbit Beamed Energy eXperiment (EBEX) – a demonstration at delivered power levels that only illuminate a spacecraft without causing damage to it.
    [Show full text]
  • Lectures 10 and 11 Laser Guide Stars
    Lectures 10 and 11 Laser Guide Stars Claire Max Astro 289, UC Santa Cruz February 11 and 16, 2016 Page 1 First, some images of the summit of Mauna Kea, HI • Keck 2 Subaru Page 2 • Movie of 3 lasers in operation on Mauna Kea, HI: https://vimeo.com/24338510 Page 3 Outline of lectures on laser guide stars • Why are laser guide stars needed? • Principles of laser scattering in the atmosphere – Rayleigh scattering, resonant scattering from sodium • What is the sodium layer? How does it behave? • Physics of sodium atom excitation • Lasers used in astronomical laser guide star AO • Wavefront errors for laser guide star AO Page 4 Laser guide stars: Main points • Laser guide stars are needed because there aren’t enough bright natural guide stars in the sky – Hence YOUR favorite galaxy probably won’t have a bright enough natural guide star nearby • Solution: make your own guide star using lasers – Nothing special about coherent light - could use a flashlight hanging from a “giant high-altitude helicopter” – Size on sky has to be ≲ diffraction limit of a WFS sub-aperture • Laser guide stars have pluses and minuses: – Pluses: can put them anywhere, can be bright – Minuses: NGS give better AO performance than LGS even when both are working perfectly. High-powered lasers are tricky to build and work with. Laser safety is added complication. Page 5 Two types of laser guide stars in use today: “Rayleigh” and “Sodium” • Sodium guide stars: excite atoms in “sodium layer” at ~ 95 km altitude of ~ 95 km • Rayleigh guide stars: Rayleigh scattering from air molecules sends light back into telescope, h ~ 10 km 8-12 km • Higher altitude of sodium layer is closer to sampling the same turbulence that a star from “infinity” passes Turbulence through Telescope Page 6 Reasons why laser guide stars can’t do as well as bright natural guide stars 1) Laser light is spread out by turbulence on the way up.
    [Show full text]
  • A History of Anti-Satellite Programs
    A History of Anti-Satellite ProgrAms January 2012 By Laura Grego, senior scientist, UCS Global Security Program ore than 5,000 satellites have been launched mainly passive support functions, satellites now play a into orbit and more than 950 still operate much more active role in “force enhancement” during wartime: today. Because these satellites provide in- other essential military support tasks such as secure and formation and other services that are in- high-volume unsecured communications, targeting and navi- Mcreasingly critical for national security, economic vitality, and gation services, weather prediction, and battle assessment. human well-being, their owners are increasingly concerned These applications are pursued largely by the United States, about keeping them safe—for as long as there have been but other countries are increasingly able to use satellites satellites there have been plans for interfering with them. for such active military support as well. Commercial satel- The act of destroying a satellite can damage the space lites have also expanded in their technical capabilities, now environment by creating dangerous amounts of space debris. offering capabilities that used to be the sole province of What’s more, the impairment or governments, such as high- loss of an important satellite, such The act of destroying a satellite resolution imagery and secure as one used for reconnaissance, can can damage the space environment by communications. quickly escalate a conflict or gen- This widening range of erate other unpredictable and dan- creating dangerous amounts of space services is now essential to our gerous consequences. And short of debris. What’s more, the impairment civilian, scientific, and eco- an actual attack on a satellite, even nomic life as well as our mili- the targeting of satellites or the or loss of an important satellite tary operations.
    [Show full text]
  • Does the United States Need Space-Based Weapons?
    After you have read the research report, please give us your frank opinion on the contents. All comments—large or small, complimentary or caustic—will be gratefully appreciated. Mail them to CADRE/AR, Building 1400, 401 Chennault Circle, Maxwell AFB AL 36112-6428. Does the United States Spacy Need Space-Based Weapons? Thank you for your assistance COLLEGE OF AEROSPACE DOCTRINE, RESEARCH, AND EDUCATION AIR UNIVERSITY Does the United States Need Space-Based Weapons? WILLIAM L. SPACY II Major, USAF CADRE Paper Air University Press Maxwell Air Force Base, Alabama 36112-6610 September 1999 Disclaimer Opinions, conclusions, and recommendations expressed or implied within are solely those of the author, and do not necessarily represent the views of Air University, the United States Air Force, the Department of Defense, or any other US government agency. Cleared for public release: distribution unlimited. ISBN 1-58566-070-1 ii CADRE Papers CADRE Papers are occasional publications sponsored by the Airpower Research Institute of Air University’s College of Aerospace Doctrine, Research, and Education (CADRE). Dedi- cated to promoting understanding of air and space power theory and application, these studies are published by the Air University Press and broadly distributed to the US Air Force, the Department of Defense and other governmental organiza - tions, leading scholars, selected institutions of higher learning, public policy institutes, and the media. All military members and civilian employees assigned to Air University are invited to contribute unclassified manuscripts. Manuscripts should deal with air and/or space power history, theory, doctrine or strategy, or with joint or combined service matters bearing on the application of air and/or space power.
    [Show full text]
  • Results of the Compensated Earth–Moon–Earth Retroreflector Laser
    TDA Progress Report 42-131 November 15, 1997 Results of the Compensated Earth–Moon–Earth Retroreflector Laser Link (CEMERLL) Experiment K. E. Wilson Communications Systems and Research Section P. R. Leatherman, R. Cleis, J. Spinhirne, and R. Q. Fugate Air Force Laboratory, Kirtland Air Force Base, New Mexico Adaptive optics techniques can be used to realize a robust low bit-error-rate link by mitigating the atmosphere-induced signal fades in optical communications links between ground-based transmitters and deep-space probes. Phase I of the Com- pensated Earth–Moon–Earth Retroreector Laser Link (CEMERLL) experiment demonstrated the rst propagation of an atmosphere-compensated laser beam to the lunar retroreectors. A 1.06-m Nd:YAG laser beam was propagated through the full aperture of the 1.5-m telescope at the Starre Optical Range (SOR), Kirt- land Air Force Base, New Mexico, to the Apollo 15 retroreector array at Hadley Rille. Laser guide-star adaptive optics were used to compensate turbulence-induced aberrations across the transmitter’s 1.5-m aperture. A 3.5-m telescope, also located at the SOR, was used as a receiver for detecting the return signals. JPL-supplied Chebyshev polynomials of the retroreector locations were used to develop track- ing algorithms for the telescopes. At times we observed in excess of 100 photons returned from a single pulse when the outgoing beam from the 1.5-m telescope was corrected by the adaptive optics system. No returns were detected when the outgo- ing beam was uncompensated. The experiment was conducted from March through September 1994, during the rst or last quarter of the Moon.
    [Show full text]
  • Comparison of Na Lidar and Meteor Radar Wind Measurements at Starfire Optical Range, NM, USA
    Physical Sciences - Daytona Beach College of Arts & Sciences 2002 Comparison of Na Lidar and Meteor Radar Wind Measurements at Starfire Optical Range, NM, USA Alan Z. Liu Embry Riddle Aeronautical University - Daytona Beach, [email protected] Wayne K. Hocking Steven J. Franke T. Thayaparan Follow this and additional works at: https://commons.erau.edu/db-physical-sciences Part of the Physical Sciences and Mathematics Commons Scholarly Commons Citation Liu, A. Z., Hocking, W. K., Franke, S. J., & Thayaparan, T. (2002). Comparison of Na Lidar and Meteor Radar Wind Measurements at Starfire Optical Range, NM, USA. Journal of Atmospheric and Solar-Terrestrial Physics, 64(). Retrieved from https://commons.erau.edu/db-physical-sciences/34 This Article is brought to you for free and open access by the College of Arts & Sciences at Scholarly Commons. It has been accepted for inclusion in Physical Sciences - Daytona Beach by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. Journal of Atmospheric and Solar-Terrestrial Physics 64 (2002) 31–40 www.elsevier.com/locate/jastp Comparison of Na lidar and meteor radar wind measurements at Starÿre Optical Range, NM, USA Alan Z. Liua;∗, Wayne K. Hockingb, Steven J. Frankea, T. Thayaparanc aDepartment of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA bUniversity of Western Ontario, Canada cDefense Research Establishment, Ottawa, Canada Received 20 February 2001; received in revised form 26 September 2001; accepted 18 October 2001 Abstract Simultaneous wind measurements in the mesopause region at Starÿre Optical Range near Albuquerque, NM with Na wind=temperature lidar and meteor radar have been performed and compared.
    [Show full text]
  • Acronym Dictionary and Glossary
    Acronym Dictionary and Glossary CSR ACRONYM DEFINITIONS CSR Acronym Definitions A-D http://www.csrstds.com/acro-a-d.htm. CSR Acronym Defintions E-H http://www.csrstds.com/acro-e-h.htm. CSR Acronym Definitions I-M http://www.csrstds.com/acro-i-m.htm. CSR Acronym Definitions N-R http://www.csrstds.com/acro-n-r.htm. Acronym Definitions last updated November 26, 2001. If you have changes or corrections, please e-mail them to [email protected]. Thank you. Communications Standards Review e-mail: [email protected] SSEC Acronyms List SSEC Acronyms List http://www.ssec.wisc.edu/pubs/acronyms.htm. Updated 17 December 2001 by the SSEC Webmaster. (current December 2001) ANSI ASC X12N - Acronym Dictionary OCTOBER 1997 ASC X12N ACRONYM DICTIONARY http://www.wpc-edi.com/AcronymDictionary/Index.html ASC X12N ACRONYM DICTIONARY http://www.wpc-edi.com/AcronymDictionary/Dictionary.html Acronym Dictionary http://www.wpc-edi.com/AcronymDictionary/Dictionary.htm. Dictionary A List of Xcellweb Features plus a collection of Internet expressions Xcellweb Services/Dictionary http://www.xcellweb.com/html/dictionary.htm. [email protected] (503) 968-4307 MAD The MIPS Acronym Dictionary Don't get even, get MAD! [email protected] Sunday, October 28, 2001 Leviton Manufacturing Co., Inc. © Copyright 1998 www.levitontelcom.com • e-mail: [email protected] Newton’s Telecom Dictionary BABEL: A LISTING OF COMPUTER ORIENTED ABBREVIATIONS AND ACRONYMS Date Updated: 10/20/93 Version 93C Copyright (c) 1989-1993 Irving Kind All Rights Reserved Irving Kind Internet: [email protected] c/o K &D MCIMail: 545-3562 One Church Lane Baltimore, MD 21208 Sep 1993 version = BABEL93C Sep 1994 version = BABEL94C CSGNetwork's Online Computer, Telephony & Electronics Reference Computer Support Group & CSGNetwork.Com Online Computer, Telephony and Electronics Glossary and Dictionary wysiwyg://79/http://www.csgnetwork.com/glossaryp.htm.
    [Show full text]
  • Green Laser Green Laser Pointers: SMART
    GreenGGrreeeenn LL Laseraasseerr Pointers: SMART Use RASC GLP Committee RASC GLP Committee RASC GLP Committee I2010 marks 50 years since the “invention” of the laser. The laser (Light Amplification by Stimulated Emission of Radiation), in common with rocket- propelled space travel, electronic computing, and nuclear fusion, is seen as a classic technology of the modern age. One of the fathers of the laser, Nobel Prize winner Charles H. Townes, memorably characterized its invention as a ―solution looking for a problem‖(1). Applications in daily life and research have multiplied, along with improvements in the technology, towards a greater choice of wavelengths, dramatically increased power, and ever decreasing costs. Astronomers are among the beneficiaries of these developments, but maturity of technology is not always matched by maturity of use, and we may yet find our access to lasers for education and public outreach (EPO) severely curtailed by the immature actions of others. LaserI s owe their effectiveness to the coherence, amplification, and narrow divergence of the beam of monochromatic (single wavelength) light they emit. In simple terms, coherence occurs when waves are in a constant phase relationship (wave peaks and troughs are in step), amplification develops through the process described below, and narrow divergence results when the increase in beam diameter over distance is limited. How do lasers work? Energy is fed through a gain medium (e.g., gas, or crystal) by an energy pump raising electrons to a higher energy state; when the electrons in the higher energy state outnumber those in the ground state, population inversion occurs, leading to higher levels of stimulated emission (i.e., an electron perturbed by a photon drops to a lower energy level releasing another photon), and more coherent light passes through the system than is absorbed.
    [Show full text]