international laser ranging service 2007–2008 · 2012-08-07 · 2007-2008 ilrs annual report i i...
TRANSCRIPT
2007–2008
I N T E R N A T I O N A L L A S E R R A N G I N G S E R V I C E
November 2009
Edited by C. Noll and M. Pearlman
R E P O R T
NASA/TP-2010-215848Goddard Space Flight CenterGreenbelt, MD 20771
Available From:
NASA Center for Aerospace Information National Technical Information Service7121 Standard Drive 5285 Port Royal RoadHanover, MD 21076-1320 Springfield, VA 22161Price Code: A17 Price Code: A10
2007-2008 ILRS Annual Report ii
Preface
This 2007-2008 volume is the sixth published report for the International Laser Ranging Service (ILRS). This edition once again concentrates on achievements and work in progress rather than ILRS organizational elements. The 2007-2008 ILRS report is structured as follows
• Section1–ILRSOrganization,reviewstheserviceanditsroleinspacegeodesy. • Section2–ILRSTrackingNetwork,providesthecurrentstatusandrecentperformancestatisticsofthe internationalstationssupportingtheILRSandoffersaperspectiveonsitesurveysandsystemco-locations. Anupdateonfieldengineeringactivitiesisalsoprovided. • Section3–ILRSMissionsandCampaigns,givesinformationaboutmanyofthecurrentandfuturemissions supportedbytheILRS. • Section4–Infrastructure,detailsrecentactivitiestackledbytheILRSCentralBureau,includingWebsite improvements and data center developments. • Section5–TrackingProceduresandDataFlow,discussessatellitepredictions,ILRStrackingpriorities,recent developmentsintheareaofdynamicpriorities,andtheflowofon-sitenormalpointsandfull-ratedata. • Section6–EmergingTechnologies,includesinformationabouthighrepetitionratelasersandsystems, detectors,timersandfrequencystandards,multi-wavelengthranging,andotherhardwarethatwillhelp advancetheaccuracyandautomationoflaserrangingsystems.Alsoincludedarenewapplicationsforthe SLRtechnique. • Section7–AnalysisActivities,reviewstherecentdevelopmentsintheILRSAnalysisWorkingGroup and plans for future products. • Section8–Modeling,discussesrecentadvancementsinrefractionmodelingandsatellitecenterofmass corrections. • Section9–ScienceReportexaminestheILRSroleintheITRF,itssynergywiththeothergeodetictechniques, and some interesting applications for both SLR and LLR. • Section10–MeetingsandReports,reviewsILRS-relatedmeetingsin2007-2008andreportsissuedbythe service over that period. • Section11–Bibliography,listssomeofthepapersandpresentationsaboutSLRandLLRscienceand technologymadeduring2007-2008. • Section12–AC,AACandLunarAACReports,presentsindividualsummariesfromILRSanalysis,associate analysis,andlunarassociateanalysiscenters. • Section13–StationReports,includesinformationreceivedfromthestationscontributingtotheILRSnetwork. • Appendix–ILRSInformation,listsorganizationsparticipatingintheILRSanddefinesacronymsusedin this report.
ThisreportisalsoavailablethroughtheILRSWebsiteatURLhttp://ilrs.gsfc.nasa.gov/reports/ilrs_reports/ilrsreport_2007.html.
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Forfurtherinformation,contacttheILRSCentralBureau:
CareyNollSecretary,ILRSCentralBureauNASAGoddardSpaceFlightCenterCode690.1Greenbelt,[email protected]
MichaelPearlmanDirector,ILRSCentralBureauHarvard/SmithsonianCenterforAstrophysics60GardenStreetCambridge,[email protected]
ILRSWebsite:http://ilrs.gsfc.nasa.gov
AcompletelistofILRSassociatescanbefoundontheILRSWebsiteathttp://ilrs.gsfc.nasa.gov/contact_ilrs/ilrs_directory.html.
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The editors would like to acknowledge the essential contributions from our ILRS colleagues to this 2007-2008 edition of the ILRS report.
acknowledgement
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table of contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Dedication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chairman’s .Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Section .1 .– .ILRS .Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Section .2 .– .ILRS .Tracking .Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Section .3 .– .ILRS .Missions .and .Campaigns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Section .4 .– .Infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Section .5 .– .Tracking .Procedures .and .Data .Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Section .6 .– .Emerging .Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Section .7 .– .Analysis .Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Section .8 .– .Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Section .9 .– .Science .Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Section .10 .– .Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
Section .11 .– .Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1
Section .12 .– .AnalysisCenter,AssociateAnalysisCenter,andLunarAssociateAnalysisCenterReports . . . . . . . . 12-1Analysis Center Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1
ItalianSpaceAgency/SpaceGeodesyCenter“G.Colombo”(ASI/CGS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1BundesamtfürKartographieundGeodäsie(BKG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-5DeutschesGeodätischesForschungsinstitute(DGFI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7GeoscienceAustralia(GA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-10HelmholtzCentrePotsdamGeoForschungsZentrumGermanResearchCentreforGeosciences(GFZ) . . . 12-12GroupedeRechercheenGeodesieSpatiale(GRGS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14JointCenterforEarthSystemsTechnology/GoddardSpaceFlightCenter(JCET/GSFC) . . . . . . . . . . . . . 12-16NaturalEnvironmentResearchCouncil(NERC)SpaceGeodesyFacility(NSGF) . . . . . . . . . . . . . . . . . . 12-22
Associate Analysis Center Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-25CenterforOrbitDeterminationinEurope(CODE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-25TheUniversityofTexasCenterforSpaceResearch(CSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-27DelftUniversityofTechnology(DUT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-31EuropeanSpaceOperationCentre(ESOC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-33ForsvaretsForskningsinstitutt(FFI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-35MainAstronomicalObservatoryoftheNationalAcademyofSciencesofUkraine(GAOUA) . . . . . . . . . 12-37HitotsubashiUniversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-40
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InstituteofAppliedAstronomy(IAA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-42Information-AnalyticalCenter(IAC),formerlyMissionControlCenter(MCC) . . . . . . . . . . . . . . . . . . . . 12-44JapanAerospaceExplorationAgency(JAXA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-46NewcastleUniversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-49NationalInstituteofInformationandCommunicationsTechnology(NICT) . . . . . . . . . . . . . . . . . . . . . . . 12-50ShanghaiAstronomicalObservatory(SHAO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-52
Lunar Associate Analysis Center Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-54InstitutFuerErdmessung/ForschungseinrichtungSatellitengeodaesie(IFE/FESG) . . . . . . . . . . . . . . . . . 12-54JetPropulsionLaboratory(JPL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-57ParisObservatoryLunarAnalysisCenter(POLAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-59
Section .13 .– .Station .Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1Arequipa,Peru . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1Beijing,China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4Borowiec,Poland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7Changchun,China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-10Concepción,Chile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-13FTLRS,France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-16Grasse,France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-18Graz,Austria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-20GreenbeltMD(MOBLAS-7),USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-23GreenbeltMD(NGSLR),USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-25HaleakalaHI,USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-27Hartebeesthoek,SouthAfrica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-29Helwan,Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-31Herstmonceux,UK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-34Kiev,Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-37Kunming,China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-39Lviv,Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-41Matera,Italy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-44McDonaldTX,USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-47Metsahovi,Finland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-50MonumentPeakCA,USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-52MountStromlo,Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-54Potsdam,Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-57Riga,Latvia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-58Riyadh,SaudiArabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-61SanFernando,Spain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-63SanJuan,Argentina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-65Shanghai,China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-68Simeiz,Ukraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-71Simosato,Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-73
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Tanegashima,Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-74Wettzell,Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-76Yarragadee,Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-78Zimmerwald,Switzerland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-80
Appendix .– .ILRS .Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1ILRS .Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
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ItiswithdeepsadnessthattheILRScommunitylearnedofthedeathofProf.Dr.WernerGurtnerfromcanceronOctober24,2009shortlyafterhissixtiethbirthday.
WernerGurtnercompletedhisstudiesinSurveyingEngineeringin1973attheInstituteofGeodesyandPhotogrammetryoftheETHinZurich,Switzerland.From1974to1979hewasaresearchassistantandPh.D.candidatewithProf.MaxSchuerer,whowasalecturerat theETHinadditiontohispositionasdirectoroftheAIUB.Werner’sPh.D.thesis,partlywritteninBern,resultedin a well-known reference, the “Geoid of Switzerland” using astrometricobservations.
WernerstartedhisofficialemploymentwiththeAIUBinJanuary1980.Asearlyas1978,attheETH,hestartedworkonthenewZimmerwaldobservatory,dedicatedtoSatelliteLaserRanging(SLR)andin1987hebecamethedirectoroftheZimmerwaldFundamentalObservatory.Between1992and1996heledtheAIUB team,which planned and realized the new SLR and astrometrytelescope in Zimmerwald. In collaboration with the Canton of Bern, theUniversity of Bern, the SwissNational Science Foundation, and the SwissFederalOfficeofTopography,theone-metercombinedSLRandastrometry
telescopewas deployed atZimmerwald and became one of the essential pillars of the InternationalLaserRangingService (ILRS).With this same energy,Werner organized the upgrade of the observatory during 2005-2008. Thisupgrade includedanewlasercapableofperformingdual-colormeasurementsaswellassupporting futureone-wayrangingandtransponderexperiments.TheZimmerwaldObservatoryasestablishedbyWernerisrecognizednowasoneoftheforemoststationsintheglobalspacegeodesycommunityfromthescientific,technical,andadministrativepoints of view.
Duringthe1980’sWerneralsoworkedontheteamthatsuccessfullydevelopedwhatwouldeventuallybeknownastheBerneseGPSSoftwarepackage.Inthe1990’s,hewasoneofthekeypersonsinthedevelopmentoftheInternationalGNSSService(IGS).HiscontributionsrelatedtoIGSdatatransferandinformationdisseminationwereofgreatimportanceandatleastinpartresponsiblefortheworldwideacceptanceoftheIGS.TheReceiverINdependentEXchange(RINEX)format,whichheinitiatedandcoinedtoagreatextent,becameastandardastheplatformforexchangingGNSSdatainbothscienceandengineeringapplications.WernercontinuedtoworkonenhancementstoRINEXuntilveryrecently.Theglobal acceptanceofRINEX inboth the scienceand receiver technologycommunities is a tribute toWerner’sforesight.
WernerhelpedtheInternationalAssociationofGeodesy(IAG)todevelopessentialstructuralelementsrelatedtospacegeodesy.HewasamemberoftheveryactiveEUREFTechnicalWorkingGroupsince1992;hechairedthisgroupfrom1999to2003.HewasnotonlyakeypersononthedevelopmentoftheIGS,butalso,eventoamuchgreaterextent,forthedevelopmentoftheILRS.WernerGurtnerwasamemberoftheILRSGoverningBoardsinceitsinceptionin1998andservedasChairoftheBoardfrom2002to2009.BeforethattimehechairedEUROLAS,anassociationofEuropeanSLRobservatories.Wernerwasan important linkbetween thevariousspacegeodesycommunities,particularly theILRSandIGS.
Professor Dr. Werner Gurtner, 1949-2009Astronomical Institute of Bern, Switzerland
dedication
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TheFacultyofSciencesoftheUniversityofBernacknowledgedtheachievementsofthiseminentengineerandscientistbyawardinghimthetitleofprofessorin1999.WernerGurtnerwillberememberedascompetentcollaborator,goodfriend and dear colleague.
TheILRSwouldliketodedicatethisissueofthereportseriestothememoryofourcolleague,ProfessorDr.WernerGurtner,ingratefulrecognitionofhismanycontributionstoSLRandGNSS,theILRSandtheIGS,andthebroaderinternationalspacegeodesycommunity.WeallwillmissourassociationandinteractionswithWerner.
MichaelPearlman,Harvard-SmithsonianCenterforAstrophysics,USAGerhardBeutler,AstronomicalInstituteUniversityofBern,Switzerland
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THE INTERNATIONAL LASER RANGING SERVICE 2007-2008
InAugust,1969,NASAconveneda10-dayseminaratWilliamsCollege,Williamstown,Massachusetts.TheseminarwaschairedbyWilliamKaulaandattendedbyothervisionariesintheemergingdisciplineofsatellitegeodesy.Areportof the discussions and deliberationswas produced: “TheTerrestrialEnvironment: SolidEarth andOceanPhysics,”NASACR-1579,April,1970,whichbecameknownas“TheWilliamstownReport.”
ItwasanexcitingtimeinAugust,1969,withthefirstsuccessfulApollolandingontheMooninJulyandreturnoftheApollo-11astronautstoEarth.Theastronautshaddeployedreflectorarraystoenablestudiesofthelunarorbitalandrotationalmotionwithunprecedentedaccuracyusingthenewlaserrangingtechnology,alreadydemonstratedin1964withEarthsatellites.Infact,initiallaserreturnsfromtheApollo-11reflectorswereobtainedinAugustjustbeforeandduringtheWilliamstownmeeting.
TheWilliamstownReportacknowledgedtheimportanceoflaserranging:“Thereisnodoubtthatlaserrangingwillbe a basic technique in any future system that requiresmaximum accuracy” (page 2-7).And indeed it is the casethatlaserrangingtoartificialsatellitesandtheMoonhavebeenessentialcontributorstothesciencedescribedintheWilliamstownReport.
ItwasrecognizedveryearlythatlasertrackingofartificialsatellitesandtheMoonwouldbenefitfromaglobaldistributionofinstruments,especiallytosupportapplicationsofthetechniquetoinvestigateglobalphenomena,suchasdistributionofmasswithintheEarth(gravitationalfield)andthree-dimensionalmotionoftheEarthandMooninspace.Withthisrecognition,thecommunityorganizeditself,somewhatinformally,tobuildaglobalnetworkofSLRandLLRstations.Thisnetworkofstationsplayedkeyrolesinthemissionsofseveralsatellites,includingsatellitesspecificallydesignedtooperatewithlaserranging(suchastheLaserGeodynamicsSatellite,LAGEOS)andradaraltimetersatellitesthatcarriedretroreflectorarrays(suchasGEOS-C,SeasatandTOPEX/Poseidon).Theinformalnetworkwasaccomplishedthroughthegraciouscollaborationofinstitutionsandgovernmentagenciesofseveralnations.Thiscollaboration,whichisnowformalizedintotheInternationalLaserRangingService,continuestoprovidekeyfunctionsandservicestotheglobalgeodeticandgeophysicalcommunity.Inthemorethanfortyyearsthathaveelapsedsincethefirstexperimentsonlaserrangingtoanartificialsatellite(BeaconExplorer-B),theILRShasmaturedintoaglobalnetworkthatprovidesvitalsupport to missions. The international collaboration has been crucial to the success and the sharing of the cost among the various institutions and agencies has been essential for the network growth.
The ILRS roots canbe traced to thefirst laser rangingexperimentsonBE-B,but the ILRSnowprovides trackingsupportofnumeroussatellitesandthelistcontinuestogrow.ItisalwaysapleasuretoacknowledgethemanydedicatedcontributorstotheILRS.Thetrackingofthevarietyofsatellitesisnotonlymuchappreciated,itisessentialforthescientificapplication(andinsomecases,thetechnologicalapplications)ofthosesatellites.
Althoughtheroleoflaserranginghaschangedovertheyears,itisstillthepremiertechniqueforaspectsofthereferenceframeandforprovidinganabsolutemeasureofaccuracy.Today,SLRisusedasthesolesourceoftrackingonsomesatellites,suchasLAGEOSandStarlette,butSLRalsoprovidesanessentialroleofvalidatingtheorbitdeterminationbasedonothertechniques,suchasGPS.
The future for laser ranging is bright, with new technology and applications not envisioned by theWilliamstownReport.ThetechnologyhasemergedintheformoflaseraltimetryoftheEarth,Moon,andMars.Andone-wayrangingexperimentsareplannedfromtheEarthtolunarsatellites,forexample.Onceagain,itisanexcitingtimeaswewatch
introduction
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thesenewtechnologiesandapplicationsmovetowardfruition.Nevertheless,wecannotneglectourcoreactivitiesandresponsibilities.Wemustcontinuetoimprovetheinstrumentationbyloweringoperatingcostsandimprovingaccuracy.Thelaserrangingcommunitycontinuestobeavibrantandinnovativeinternationalcollaborationofindividualsandinstitutions,andonbehalfof thecommunityofusersof laserrangingdata, Ioffer thesincere thanksfromtheusercommunityforyourdedicationtolaserranging.
Iwasaskedthefollowingquestionssomeyearsago:howlongdoweneedtocontinuetrackingLAGEOS?HavewealreadyextractedalltheinformationabouttheLAGEOSdynamicsandvariousapplicationsofLAGEOSthatwecanandtherefore,thereisnoneedtocontinuetracking?Thesearecertainlythoughtprovokingandvalidquestions.Itisamazingtome,thataftermorethanthirtyyears,LAGEOSandStarlette,forexample,continuetobeorbitingbenchmarks.SLRnowhasthelongesttimehistoryofhighaccuracyobservationsofartificialsatellites.Wearestilllearningaboutlong-termsatellitedynamics,i.e.,orbitevolution,thereferenceframeandtheenvironmentinwhichthesatellitemoves.Andthesesatellitesandtheirapplicationsstillhavealottoteachus.Aslongaswecontinuetolearn,Iwouldarguethatweshouldcontinuetrackingsuchsatellites.Asofnow,wecontinuetolearn.
BobE.SchutzAustin,TexasNovember2,2009
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Thebi-annualreportisanopportunityfortheILRStoprovidethecommunitywiththeupdateontheServiceactivities,procedures and plans. The report also gives each of the ILRS entities the occasion to include news on recent activities and to bring us up to date on staff changes. The report also includes station performance information and activities underwaythatwillimproveperformanceinthefuture.Thisreportperiodincludessomeratherfundamentalchangesand some new challenges for the ILRS.
Networkdatayieldcontinuestoincrease.ThestationsinArequipaandHaleakalaarenowoperationalanddatayieldonGNSSsatelliteshasimproved.Daylighttracking,particularlyonthehighersatellitesisstillamajorissueonthehighersatellites,butsomeofthestationshavehadsuccesswithdaylightrangingonsomeoftheGNSSsatellitesastechnologyhas improvedwith thehigher repetitionrate lasersand tracking techniqueshavebeenrefined. Onedisappointmentduringthisperiodwasdiscoveryofsmallrangebiases,somebeingintroducebytheStanfordCounterthathavebeeninstalled in several stations. Calibration procedures provided some improvement, but thiswill not suffice as rangeaccuracyrequirementscontinuetowardthemmlevel.
The Consolidated Prediction Format (CPF) has now been fully implemented, with commensurate improvement inprediction quality. The new Consolidated Range laser range Data format (CRD), that accommodates higher rangeaccuracyandextendedone-wayandtwo-wayrangingtoplanetarydistancesisbeingimplementedasthenewILRSstandard.Itisalreadyinuseatseveralstations;fulltransitionforthenetworkisscheduledforearly2010.
ALaserWorkshopwasheldinGrasse,FranceinSeptember2007.TheSixteenthWorkshoponLaserRangingwasheldinPoznan,PolandinNovember2008.Bothworkshopsincludedaweek-longformatcoveringanalysis,rangingsystemshardwareandsoftware,andretroreflectorarraysprovidedavenueforscientists,analysts,andpractitionerstomeetanddiscusstechniqueissuesandnewideas.TheproceedingsforbothareaccessiblethroughtheILRSwebsite.Wethanktheorganizersandsponsorsofbothmeetings,theSpaceResearchCentreofthePolishAcademyofSciencesandtheObservatoiredelaCoteD’Azure,forthetheirexcellentarrangementsandwonderfulhospitality.Theworkshopswerecertainlyhighlightsofthisreportingperiod.TheSeventeenthWorkshoponLaserRangingwillbeheldinConcepcion,ChileinNovember2010.
Bytheendof2008, theILRScommunitywasassemblingitsdataproductforsubmissionfor theITRF2008.Eightanalysiscenterswerepreparingtheirsolutionsoftime-dependentstationpositionsforsubmissiontotheCombinationCentersattheASIandDGFI.
AnumberofnewsatelliteswereaddedtotheILRSrosterduringthisperiod.TerraSAR-X,andJason-2(withtheT2L2timingexperiment)aremakingfundamentalcontributions toEarthScience.ThreenewGNSSsatelliteswereaddedduring thisperiod includingGLONASS115,GIOVE-B,andCompass-M1.Ofparticularnote,bothGLONASS115andCompass-M1 carried retroreflector arrayswith uncoated cubes for improved array effective cross-section. Theimprovementindatayieldwasquiteevident.
TheILRScontinueditssupporttheIAG’sGlobalGeodeticObservingSystem(GGOS).Thebook,“GlobalGeodeticObservingSystem:MeetingtheRequirementsofaGlobalSocietyinaChangingWorld”withanumberofcontributionsfrom the ILRS, has beenpublishedbySpringer.Tohelp support future spacegeodesy requirements, the ILRShasundertakenasimulationactivitytohelpscopefuturenetworkdesign.
Iwouldliketothankallofourcolleaguesinthetrackingnetwork,attheCentralBureau,theanalysisanddatacenters,thosewhoundertookadditionaldutiesasworkinggroupchairsormembers,fortheircontinuouscontributiontoourService.Specialthanksofcoursetotheagencies,institutionsandfoundationsfortheirongoingfinancialsupportofouractivities.
WernerGurtnerChairman,ILRSGoverningBoardAstronomical InstituteBern,SwitzerlandSeptember2009
chairman’s remarks