SATELLITE LASER RANGING OBSERVATIONS IN 1997

SATELLITE LASER RANGING OBSERVATIONSIN1997
Summary - Satellite laser ranging observations have been continued by a fixed type satellite laser ranging
station at the Simosato Hydrographic Observatory (JHDLRS-1) and by a transportable one(HTLRS) .
Key words: satellite laser ranging(SLR) - global geodesy - JHDLRS-1 - HTLRSThis is a report of the satellite laser ranging (SLR) observations made at the Simosato Hydrographic
Observatory by a fixed type satellite laser ranging station called JHDLRS-1 (Sasaki et al., 1983) and by atransportable one called HTLRS (Sasaki, 1988). This report contains the lists of data obtained at thesestations in 1997.
Previous data obtained by the JHDLRS-1 appear in the Series of Astronomy and Geodesy, Data
Report of Hydrographic Observations for the period from 1982 to 1985, and in the Series of Satellite
Geodesy from 1986 to 1996; those obtained by the HTLRS appear in the Data Report of Hydrographic
Observation, Series of Satellite Geodesy, No. 3 - 11.
1. Observation
The routine ranging observation for Lageos-I, Starlette, and Beacon (BE)-C started in April 1982 by
the JHDLRS-1 under the mutual cooperation between the Hydrographic Department of Japan (JHD) and theNational Aeronautics and Space Administration (NASA) of the United States of America. In August 1986,
the Japanese first Geodetic Satellite "Ajisai" was launched and its tracking observation by the JHDLRS-1started. Thereafter, 14 satellites were added in the routine observation : "ERS-1" in July 1991, "TOPEX/POSEIDON" in August 1992, "Lageos-II" in October 1992, "Stella" in September 1993, "Meteor-3" inJanuary 1994, "Etalon-1","Etalon-2" in November 1994 ,"ERS-2" in May 1995, "GFZ-1" in June 1995,"GPS-35","GPS-36" in August 1995, and "ADEOS" in October 1996, "DIADEM1C", "DIADEM1D" inMay 1997.
The range observation for Lageos-I, Starlette and Ajisai, by the HTLRS started in December 1987 ina campaign style. Lageos-II, ERS-1, TOPEX/POSEIDON and Stella have been also observed by theHTLRS . The range observations by the HTLRS at off-lying islands and at some coastal areas have been
carried out as follows.
Jan. 1988 - Mar. 1988

: Titi SimaJul.

: Isigaki Sima

1988 - Sep. 1988

Jan. 1989 - Mar. 1989

: Minamitori SimaJul.

: Okinawa Sima

1989 - Sep. 1989

Oct. 1989 - Nov. 1989

: Tusima

Sep. 1990 - Oct. 1990

: Oki Shoto

Dec. 1990 - Feb. 1991

: Minami-Daito Sima

Aug. 1991 - Nov. 1991

: TokatiJan. 1992 - Mar. 1992

: Iwo Sima

Aug. 1992 - Oct. 1992

: Wakkanai

Jan. 1993 - Mar. 1993

: Hatizyo Sima

Jan. 1994 - Mar. 1994

: MakurasakiJul.

1994 - Oct. 1994

: OgaFeb. 1995 - Mar. 1995

: Bisei‑1‑SATELLITE LASER RANGING OBSERVATIONS IN 1997
Jul.

1995 - Aug. 1995

: BiseiJan. 1996 - Mar. 1996

: Tyosi

Sep. 1996 - Dec. 1996

: Titi SimaJul.

: Isigaki Sima

1997 - Nov. 1997

The major specifications of the JHDLRS-1 and the HTLRS are listed in Table 1 and Table 2 (Sasakiet al., 1983, Sasaki, 1988). The locations of the systems and fiducial stone markers set up near the systems
are shown in Table 3 (Takemura, 1983) and Table 4.
The observation schedule of the JHDLRS-1 was made by selecting passes whose maximum
elevation were over 30 degrees for Starlette, Ajisai, ERS-1, ERS-2, TOPEX/POSEIDON, Stella, Etalon-1,Etalon-2 and GFZ-1, ADEOS, GPS-35, GPS-36, and over 30 degrees in the nighttime and 35 degrees in thedaytime for Lageos-I and Lageos-II. The observation schedule of the HTLRS was made by selecting passes
whose maximum elevations were over 20 degrees only in the nighttime. When the HTLRS was in operation,
the same criterion was applied to the JHDLRS-1. Routine observation was not carried out on Saturday andSunday. The priority of the selection for simultaneous transits was in the order of Ajisai, Lageos, ERS,TOPEX/POSEIDON, Starlette, Stella, GFZ-1, Etalon, and GPS.
IRV orbital elements of the satellites obtained from the Goddard Space Flight Center(GSFC) ofNASA via ftp were used for scheduling and tracking. The tracking was carried out when the elevation ofsatellites was above 20 degrees. The temperature, atmospheric pressure and relative humidity weremeasured once in a pass. Before and after ranging satellites, the ranging calibrations were made by using aground target.
In order to improve ranging precision, the JHDLRS-1 has been upgraded several times. A MicroChannel-Plate photomultiplier was introduced in the JHDLRS-1 in January 1985. A GPS clock wasintroduced into the JHDLRS-1 in December 1988 to monitor and correct the atomic clock used in thesystem, and it has been in operation since April 1989. A GPS clock has been also used in the HTLRS. Alaser subsystem of the JHDLRS-1 was upgraded to a Quantel YAG 460-5 at the beginning of June 1990.
Receiving electronics was also upgraded and RMS was improved in December 1993.
The total numbers of returns and passes obtained by the JHDLRS-1 at Simosato and by theHTLRS at Isigaki Sima in 1997 are listed in Table 5 and Table 6.
2. Polynomial fitting and preliminary analysis of range data
False range data were removed by a visual rejection system. The system works on CRT screens byapplying a filter of polynomial fitting to measured range itself by use of the on-site computer. Preliminary
values of standard deviation for each pass were estimated in this process.

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SATELLITE LASER RANGING OBSERVATIONS IN 1997

A part of obtained data, named quick-look (QL) data, were sent to the GSFC from Simosato within
one day through INTERNET. QL data of TOPEX/POSEIDON was sent to the GSFC from Simosato within
8 hours through INTERNET. QL data of ERS-1, ERS-2, and GFZ-1 were also sent to the Deutsches
Geodatisches Forschungsinstitut (DGFI) within one day through INTERNET. All the range data, after
application of the correction of the internal time delay of the SLR systems obtained by the ground target
ranging, named full-rate (FR) data, were recorded on a hard disk in MERIT-II Format (CSTG, 1987)
together with the satellite ID, the station ID, the transmitted time corrected into UTC (USNO MC), themeteorological data, the preliminary measurement standard deviation and some preprocessing indications.
All the FR data were sent to the GSFC.
The weighted mean range precisions estimated by using the polynomial fitting for all the dataobtained by the JHDLRS-1 in 1997 are 6.1cm for Lageos-I, 4.7cm for Lageos-II, 3.6cm for Starlette, 4.4cmfor Ajisai, 3.5cm for ERS-2, 3.8cm for TOPEX/POSEIDON, 3.9cm for Stella, 10.4cm for Etalon-1, 9.3cm
for Etalon-2, and 2.8cm for GFZ-1, 3.3cm for ADEOS, 4.6cm for DIADIME1C, 4.4cm for DIADIME1D,respectively, as shown in Table 5. The same for the HTLRS at Isigaki Sima are 6.1cm for Ajisai, 5.5 cm for
Lageos-I, 4.2cm for Lageos-II, 17.2cm for ERS-2, 10.1cm for Starlette, 3.6cm for Stella, 7.2cm for
TOPEX/POSEIDON, respectively, as shown in Table 6.
The QL data sent to the GSFC were used to update orbital elements. These data were transferredfrom the GSFC to the Center for Space Research(CSR) of the University of Texas at Austin and were used
for the estimation of the polar motion and the variation of the angular velocity of the earth rotation byprocessing with the SLR data from other sites in the world. All the FR data were also analyzed in the CSR
and other SLR analysis centers, and more precise values for the earth rotation parameters have been
estimated. The FR data sent to the GSFC were used to detect crustal movements and global plate motions.
The JHD has been processing FR data obtained at Simosato and other SLR sites by using an original
orbital processor (Sasaki, 1984) and GEODYN-II/SOLVE made by NASA(Eddy et al., 1990). A result of
the geodetic coordinates for the cross point of azimuth and elevation axes of the JHDLRS-1, obtained as theMarine Geodetic Result (Tatsuno and Fujita, 1994), is 33゜34' 39."700N, 135゜56' 13."337E, 101.62 m for
latitude, longitude and height above the reference ellipsoid of 6378137m semi-major axis and 1/298.257223563 flattening, respectively.
The observations of satellite laser ranging were made by K. Muneda, H. Daimon, Y. Takanashi, Y.
Narita, N. Koshin, M. Takahashi, E. Kurihara and S. Kobayashi of the Simosato Hydrographic Observatory
and K. Matsumoto, K.Koyama, K. Terai, N. Ikeda, K. Sawada, H. Fukura and H. Watanabe of the JHD
Headquarters.
Calculations and compilation for this report have been made by K. Koyama, T. Kato, H. Fukura andN. Seo of the JHD Headquarters.

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SATELLITE LASER RANGING OBSERVATIONS IN 1997

References
CSTG, 1987: Satellite Laser Ranging Newsletter SLR subcommission of the CSTG (InternationalCoordination of Space Techniques for Geodesy and Geodynamics), 2, No. 1, p. 5.
Eddy et al., 1990: W. F., J. J. McCarthy, D. E. Pavlis, J. A. Marshall, L. S. Tsaoussi, G. Leung, F. A.
Williams, GEODYN-II System Operations Manual, Vol.1-5, Contractor Report, ST Syst. Corp.,
Lanham., Md.
Sasaki, M., Ganeko, Y., Harada, Y., 1983: Data Report of Hydrogr. Obs., Series of Astronomy andGeodesy, 17, p. 49.
Sasaki, M., 1984: Report of Hydrogr. Res., 19, p. 107.
Sasaki, M., 1988: Data Report of Hydrogr. Obs., Series of Satellite Geodesy, 1, p. 59.
Takemura, T., 1983: Data Report of Hydrogr. Obs., Series of Astronomy and Geodesy, 17, p. 44.
Tatsuno, T., Fujita, M., 1994: Data Report of Hydrogr.obs., Series of Satellite Geodesy, 7, p.102
USNO, 1996, 1997: Daily Time Differences and Relative Phase Values, Series 4, 1561 - 1513.

The reports of the SLR observations for the preceding years were presented in the following numbersof the Data Report of Hydrographic Observations.
Sasaki, M., Nagaoka, M., 1984: Data Report of Hydrogr. Obs., Series of Astronomy and Geodesy, 18, p.55
(for 1982).
Sasaki, M., Sengoku, A., Nisimura, E., Nagaoka, M., 1985: ibid., 19, p. 50 (for 1983).
Sasaki, M., Sengoku, A., Nagaoka, M., Nisimura, E., 1986: ibid., 20, p. 44 (for 1984).
Kanazawa, T., Sengoku, A., Nagaoka, M., Nisimura, E., 1987: ibid., 21, p. 63 (for 1985).
Kanazawa, T., Sengoku, A., Nagaoka, M., Nisimura, E., 1988: Data Report of Hydrogr. Obs., Series ofSatellite Geodesy, 1, p. 19 (for 1986).
Kanazawa, T., Sengoku, A., Nagaoka, M., Nakagawa, H., 1989: ibid., 2 , p. 1 (for 1987).
Sengoku, A., Nagaoka, M., Fuchida, K., Masai, S., Fujii, T., Nakagawa, H., 1990: ibid., 3 , p. 1 (for 1988).
Sengoku, A., Kurokawa, S., Nakagawa, H., 1991: ibid., 4, p. 1 (for 1989).
Sengoku, A., Kurokawa, S., Ikeda, N., Matsumoto, K., 1992: ibid., 5 , p. 1 (for 1990).
Sengoku, A., Murakami, S., Ikeda, N., Matsumoto, K., 1993: ibid., 6, p. 1 (for 1991).
Sengoku, A., Narita, Y., Matsumoto, K., 1994: ibid., 7 , p. 1 (for 1992).
Terai, K., Fujita, M., Matsushita, H., Muneda, K., 1995: ibid., 8, p. 1 (for 1993).
Terai, K., Fujita, M., Matsushita, H., Muneda, K., 1996: ibid., 9, p. 1 (for 1994).
Terai, K., Matsushita, H., Muneda, K., 1997: ibid., 10, p. 1 (for 1995).
K. Terai, M. Fujita, H. Matsushita, H., Muneda, K., 1998: ibid., 11, p. 1 (for 1996).

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SATELLITE LASER RANGING OBSERVATIONS IN 1997

Table 1. Principal Specifications of Satellite Laser Ranging Station of
the Simosato Hydrographic Observatory (JHDLRS-1)
Subsystem

Specification

Mount configurationElevation over azimuth/Coude pathAngular resolution

20bits (1.2 arcsec)

Transmitter diameter

17 cm

Receiver diameter

60 cm

Laser wave length

532 nmOutput energy

125 mJ

Laser pulse width

100 psRepetition rate

4 pps

Receiver detector

Micro-Channel-Plate PMT

Flight time counter

20 ps resolution

Frequency standard

Rubidium oscillator

Time comparison

GPS (TrueTime, XL-DC602)

Computer

32-bits personal computer with hard disks,
3.5inch floppy disk drive, printer, CRTs and a TA

Table 2. Principal Specifications of the Hydrographic Department
Transportable Satellite Laser Ranging Station (HTLRS)
Subsystem

Specification

Mount configuration

Elevation over azimuth/Coude pathAngular resolution

20bits (1.2 arcsec)

Transmitter diameter

10 cm

Receiver diameter

35 cm

Laser wave length

532 nmOutput energy

50 mJ

Laser pulse width

50 - 100 ps

Repetition rate

5 pps

Receiver detector

Micro-Channel-Plate PMT

Flight time counter

20 ps resolution

Frequency standard

Cesium oscillator

Time comparison

GPS (MAGNAVOX, MX4200)

Computer

16 - bits personal computers with hard disks
3.5 inch floppy disk drive, printer, CRTs and a modem‑5‑SATELLITE LASER RANGING OBSERVATIONS IN 1997

Table 3. Geodetic coordinates of JHDLRS-1
Location

Site ID

Coordinates(Tokyo Datum)
゜′″

Cross point of Az. and El. axes

International333427.496Nof JHDLRS-1

7838

13556

23.537E

Domestic

62.44mSHO-L
゜

The fiducial stone′″marker at the Simosato Hydrographic

Domestic

333428.078N

Observatory

SHO-H0135

5623.236E
58.36mTable 4. Geodetic coordinates of HTLRS
Location

Site ID

Coordinates(Tokyo Datum)
゜′″

Cross point of Az. and El. axes

International2421

5.312Nof HTLRS at Isigaki Sima

7307

124

1036.118E
55.32m゜

The fiducial stonemarker at the Isigaki Sima′″

Domestic

242154.086N

Isigaki-H1

1241254.317E
73.50m‑6‑SATELLITE LASER RANGING OBSERVATIONS IN 1997

Table 5. Data acquisition at the Simosato Hydrographic Observatory in 1997
Satellite

No. of ranges

No. of passes

RMS

Lageos-I

60,12161

6.1cm

Lageos-II

40,60541

4.7

Starlette

29,571

57

3.6

Ajisai

123,475

143

4.4

ERS-2

22,19050

3.5

TOPEX/POSEIDON

47,82060

3.8Stella10,60032

3.9

Etalon-1

1,646

410.4

Etalon-2

2,816

5

9.3

GFZ-1

812

3

2.8

ADEOS

10,70630

3.3

DIADIME1C

24,28939

4.6

DIADIME1D

9,745

20

4.4

Observers :K. Muneda, H. Daimon, Y. Takanashi, Y. Narita, N. Koshin, M. Takahashi,
E. Kurihara, S. Kobayashi,.K. Sawada*, M. Fujita*, M. Katayama*, H. Fukura*.

* JHD headquarters

Table 6. Data acquisition at Isigaki in 1997
Satellite

No. of ranges

No. of passes

RMS

Ajisai20,61134

6.1 cmLageos-I

5,175

225.5

Lageos-II

60

2

4.2ERS-2304

317.2

Starlette

55

1

10.1

Stella

374

4

3.5

TOPEX/POSEIDON

4541

97.2

Observers :K. Matsumoto, K.Koyama, K. Terai, N. Ikeda, K. Sawada, H. Fukura, Y. Sumiya,
H. Watanabe, Y. Takanasi*, M..Kurihara*, S. Kobayashi*.

*The Simosato Hydrographic Observatory‑7‑