SATELLITE LASERRANGING OBSERVATIONSIN1998
Summary - Satellite laserranging observations havebeencontinuedbyafixed type satellite laserranging
StationattheSimosatoHydrographicObservatory(JHDLRS-1) andbyatransportableone(HTLRS).
Keyword: satellitelaserranging(SLR)-global geodesy - JHDLRS-1-HTLRSThis is a report of the satellitelaserranging (SLR) observationsmade attheSimosatoHydrographic
Observatory byafixedtypesatellitelaserrangingstationcalledJHDLRS-1(Sasakietal.,1983) and b y aTransportable one calledHTLRS ( Sasaki, 1988) . This report contains the lists of data obtained at thesestations in1997
Previous data obtainedby the JHDLRS-1 appearintheSeriesofAstronomyandGeodesy , Data
Report of Hydrographic Observations for t h e p e r i o d f r o m 1 9 8 2 t o 1 9 8 5 , a n d i n t h e S e r i e s o f S a t e l l i t e
Geodesyfrom1986 to 1997;those obtained bytheHTLRSappearintheDataReportofHydrographic
Observation,SeriesofSatellite Geodesy, N o . 3 - 1 2 .
1.Observation
Theroutine rangingobservationfor Lageos-I,Starlette, and Beacon(BE)-Cstartedin April1982by
theJHDLRS-1under themutual cooperationbetweentheHydrographic Departmentofjapan(JHD)andthe
National Aeronautics andSpaceAdministration(NASA)of the UnitedStatesof America. InAugust1986,
the Japanese first Geodetic Satellite "Ajisai" waslaunched and itstracking observation bytheJHDLRS-1
started. Thereafter,15 satelliteswereaddedintheroutineobservation:"ERS-1"inJuly1991,"TOPEX/POSEIDON"inAugust 1992 , "Lageos-II"inOctober1992,"Stella"inSeptember1993, "Meteor-3" inJanuary1994,"Etalon-1","Etalon-2"inNovember1994,"ERS-2"inMay 1995,"GFZ-1"inJune1995,"GPS-35","GPS-36"inAugust 1995,and"ADEOS"inOctober 1996,"DIADEMIC", "DIADEMID"inMay1997and"WESTPAC-1"inJuly1998.
Therange observation for Lageos-I,StarletteandAjisai,bytheHTLRSstartedinDecember1987ina campaignstyle . Lageos-II,ERS-1, TOPEX / POSEIDON and Stella havebeenalsoobservedby theHTLRS.TherangeobservationsbytheHTLRSatoff-lyingislandsandatsomecoastalareashavebeen
carriedoutasfollows.
Jan.

1988- Mar. 1988

:TitiSimaJul.

1988- Sep.

:IsigakiSima

1988

Jan. 1989- Mar. 1989
Jul. 1989- Sep. 1989

: MinamitoriSima:OkinawaSima

Oct. 1989 - Nov. 1989

:Tusima

Sep. 1990- Oct.
Dec. 1990- Feb.

:OkiShoto:Minami-DaitoSima

1990
1991

Aug. 1991- Nov. 1991

:TokaiJan. 1992- Mar. 1992
Aug. 1992- Oct. 1992

:IwoSima:WakkanaiJan. 1993- Mar. 1993

:HatizyoSima

Jan. 1994- Mar. 1994

:Makurasaki

Jul. 1994- Oct. 1994
Feb. 1995- Mar. 1995

: Oga
:Bisei-1-SATELLITE LASER RANGINGOBSERVATIONS IN 1998
Jul. 1995- Aug. 1995
Jan. 1996- Mag. 1996

:Bisei:TyosiSep. 1996- Dec.

1996

:TitiSima

Jul. 1997- Nov.
Aug. 1 9 9 8 - Nov.

1997
1998

:Isigaki Sima
: IsigakiSima

Themajorspecificationsofthe JHDLRS- 1 and theHTLRSarelistedin Table1andTable2 (Sasakietal.,1983,Sasaki,1988) . Thelocationsofthesystemsandfiducialstonemarkerssetupnearthesystems
areshowninTable3 (Takemura,1983) and Table4.
Theobservation schedule o f t h e J H D L R S - 1 w a s m a d e b y s e l e c t i n g p a s s e s w h o s e m a x i m u melevation were over 30degreesfor Starlette,Ajisai,ERS-1, ERS-2,TOPEX/POSEIDON,Stella,Etalon-1,Etalon-2andGFZ-1,ADEOS,GPS-35,GPS-36,andover30degreesinthenighttimeand35degreesinthedaytimeforLageos-IandLageos-II.Theobservationschedule of theHTLRSwasmadebyselectingpasses
whose maximumelevationswereover20degrees onlyinthenighttime.Whenthe HTLRSwasinoperation,
thesame criterion wasappliedtotheJHDLRS-1.RoutineobservationwasnotcarriedoutonSaturdayand
Sunday.Thepriorityoftheselectionforsimultaneoustransitswasin the orderof Ajisai, Lageos,ERS,TOPEX/POSEIDON,Starlette,Stella,GFZ-1,Etalon,andGPS.
IRV orbital elementsofthesatellitesobtainedfromtheGoddardSpaceFlightCenterGSFC() ofNASA via ftp were usedfor schedulingandtracking. The trackingwascarriedoutwhen the elevationof
satelliteswas above 20degrees.Thetemperature,atmosphericpressureandrelativehumiditywere
measuredoncein a pass.Beforeandafterrangingsatellites,therangingcalibrationsweremadebyusinga
groundtarget.
In order toimprov ranging precision,the JHDLRS-1 hasbeen upgradedseveraltimes.A MicroChannel-Platephotomultiplierwas introduced in the JHDLRS-1 inJanuary 1985.A GPS clock wasintroduced into the JHDLRS-1in December 1988 tomonitor and correcttheatomicclock usedinthe
system,andithasbeeninoperation since April 1 9 8 9 . A G P S c l o c k h a s b e e n a l s o u s e d i n t h e H T L R S . A
laser subsystem of the JHDLRS-1 was upgradedtoaQuantelYAG 460-5atthebeginningof june 1990.
Receivingelectronics wasalsoupgradedandRMSwasimprovedinDecember1993.
The total numbers ofreturns and p a s s e s o b t a i n e d by theJHDLRS-1 a t S i m o s a t o a n d b y thein1998arelistedinTable5.
2.Polynomialfittingandpreliminaryanalysisofrange data
False rangedata wereremovedbyavisualrejectionsystem.ThesystemworksonCRTscreensby
applying a filterofpolynomial fitting tomeasuredrangeitself byuseoftheon-sitecomputer.Preliminary
values of standarddeviationforeachpasswereestimatedinthisprocess-2-SATELLITE LASER RANGINGOBSERVATIONS IN 1998
A partofobtaineddata,namedquick-look (QL ) data,were senttotheGSFCfromSimosatowithin
onedaythroughINTERNET.QLdataofTOPEX/POSEIDONwassenttotheGSFCfromSimosatowithin
8 hoursthroughINTERNET. QL d a t a o f E R S - 1 , E R S - 2 , a n d G F Z - 1 w e r e a l s o s e n t t o t h e D e u t s c h e s
Geodatisches Forschungsinstitut ( DGFI ) withinoneday throughINTERNET.Alltherangedata, afterApplicationof the correction ofthe internal time delayof the SLRsystemsobtained bythegroundtarget
ranging, named full-rate ( F R ) d a t a , w e r e r e c o r d e d o n a h a r d d i s k i n M E R I T - I I F o r m a t ( C S T G , 1 9 8 7 )together withthesatelliteID,thestation ID,thetransmittedtimecorrected intoUTC (USNO M C), t h emeteorological data,the preliminarymeasurementstandard deviationandsomepreprocessingindications.
All theFRdataweresenttotheGSFC
The w e i g h t e d m e a n r a n g e p r e c i s i o n s e s t i m a t e d b y u s i n g t h e p o l y n o m i a l f i t t i n g f o r a l l t h e d a t aobitainedbytheJHDLRS-1in1998are5.8cmforLageos-I,5.2cm for Lageos-II,4.0cmforStarlette,5.0cmforAjisai,4.6cmforERS-1,3.9cmforERS-2,4.3cmforTOPEX/POSEIDON,6.8cmforStella,11.2cm for
Etalon-1, 9.4cmforEtalon-2,and3.9cmforGFZ-1,4.7cm forGFO-1,9.8cmforGPS-36,7.6cmforWESTPAC-1,respectively,asshowninTable.

The QL data sent to the GSFC were used to update orbitalelements. These dataweretransferredfrom theGSFCtotheCenterforSpaceResearch(CSR)oftheUniversityofTexasatAustinandwereusedfor theestimation of the polar motion and the variation of angularvelocity of the earth rotation byprocessingwiththeSLRdatafromothersitesintheworld.AlltheFRdatawerealsoanalyzedintheCSR
and other SLR analysis centers, and moreprecisevaluesfortheearthrotationparametershavebeen
estimated.TheFRdatasenttotheGSFCwereusedtodetectcrustalmovementsandglobalplatemotions.
The JHD hasbeen processingFRdataobtainedatSimosato andotherSLRsitesbyusinganoriginal
orbital processor(Sasaki, 1984) andGEODYN-II/SOLVEmadeby NASA (Eddyetal.,1990).Aresultof
thegeodeticcoordinatesforthecrosspointofazimuthandelevationaxesoftheJHDLRS-1,obtainedasthe
Marine GeodeticResult (TatsunoandFujita,1994),is33 ゜34' 39."700N, 1 3 5 ゜56'13."337E,101.62m for
latitude, longitude and h e i g h t a b o v e t h e r e f e r e n c e e l l i p s o i d of 6378137m semi-major axis and 1/298.257223563flattening,repectively.

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SATELLITE LASER RANGINGOBSERVATIONS IN 1998
References
CSTG, 1987: Satellite Laser Ranging Newsletter SLR subcommission o f t h e C S T G (International
CoordinationofSpaceTechniquesforGeodesyandGeodynamics), 2, No. 1 , p . 5 .
Eddy etal.,1990: W . F . , J . J . M c C a r t h y , D . E . P a v l i s , J . A . M a r s h a l l , L . S . T s a o u s s i , G . L e u n g , F . A .
Williams,GEODYN-IISystemOperationsManual,Vol. 1-5,ContractorReport, STSyst.Corp.,
Lanham.,Md.
Sasaki, M.,Ganeko, Y . , H a r a d a , Y . , 1 9 8 3 : Data Report o f H y d r o g r . O b s . , S e r i e s o f A s t r o n o m y a n dGeodesy, 17, p . 4 9 .
Sasaki,M.,1984: Report ofHydrogr. Res ., 19,p.107.
Sasaki,M.,1988: DataReportofHydrogr. Obs.,SeriesofSatelliteGeodesy , 1, p . 5 9 .
Takemura,T.,1983: DataReportofHydrogr. Obs.,SeriesofAstronomyandGeodesy , 17, p . 4 4 .
Tatsuno,T.,Fujita,M.,1994: DataReport ofHydrogr.Obs.,SeriesofSatellite Geodesy , 7, p.102.
USNO,1996,1997:DailyTimeDifferencesandRelativePhase Values, Series 4, 1561-1513.

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Table1.PrincipalSpecifications ofSatelliteLaserRangingStationof
theSimosatoHydrographicObservatory(JHDLRS-1)
Subsystem

Specification

Mount configuration
Angularresolution

Elevationoverazimuth/Coude path
20bits(1.2arcsec)

Transmitter diameter

17cm

Receiver diameter
Laserwavelength

60cm
532nm

Outputenergy

125mJLaser pulsewidth
Repetitionrate

100ps
4pps

Receiver detector

Micro-Channel-PlatePMTFlighttime counter
Frequencystandard

20psresolution
Rubidiumoscillator

Timecomparison

GPS (TrueTime,XL-DC602)

Computer

32-bitspersonal computer withharddisks,
3.5inchfloppydiskdrive,printer,CRTsandaTA

Table2.PrincipalSpecificationsoftheHydrographic Department
Transportable Satellite Laser Ranging Station(HTLRS)
Subsystem

Specification

Mount configuration

Elevationoverazimuth/Coude pathAngularresolution
Transmitter diameter

20bits(1.2arcsec)
10cm

Receiver diameter

35cm

Laserwavelength
Outputenergy

532nm
50mJ

Laser pulsewidth50-100psRepetitionrate
Receiver detector

5pps
Micro-Channel-Plate PMT

Flighttime counter

20psresolution

Frequencystandard
Timecomparison

Cesiumoscillator
GPS (MAGNAVOX,MX4200)

Computer

16-bitspersonal computerswithharddisks
3.5inchfloppydiskdrive,printer,CRTsandamodem-5-

SATELLITE LASER RANGINGOBSERVATIONS IN 1998
Table3.GeodeticcoordinatesofJHDLRS-1
Location

SideID

Coordinates(TokyoDatum)
゜'"

CrosspointofAz.andEl.axes

International

33

34

27.496N

ofJHDLRS-1

7838
Domestic

135

56

23.537E
62.44m゜'"

SHO-L
Thefiducialstonemarker at theSimosatoHydrographic

Domestic333428.078N

Observatory

SHO-H01355623.236E
58.36mTable 4. GeodeticcoordinatesofHTLRS
Location

SideID

Coordinates(TokyoDatum)
゜'"

CrosspointofAz.andEl.axes

International

24

21

5.3546N

ofHTLRSatIsigakiSima

7307

124

1036.1016E
55.32m゜'"

Domestic

24

21

54.1213N

Isigaki-H1

1241257.3078E
73.50mThefiducialstonemarker at theIsigaki Sima

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SATELLITE LASER RANGINGOBSERVATIONS IN 1998
Table5.DataacquisitionatSimosatoHydrographicObservatoryin 1998
Satellite

No.ofranges

No.ofpasses

RMS

Ajisai
ERS-1

203,506
17,07918436

5.0
4.6

ERS-2

23,30650

3.9

Etalon-1
Etalon-2

1,576
7,899

6
11

11.2
9.4

GEOS-3

5,663

144.9

GFO-1
GFZ-1

5,456
1,464

16
4

4.7
3.9

GPS-36

375

3

9.8

LAGEOS-1
LAGEOS-2

74,933
114,688

66
82

5.8
5.2

Starlette

49,78892

4.0

StellaTOPEX

29,41384,789

5487

6.8
4.3

598

57.6

WESTPAC-1-7-