Journal of the Geodetic Society of Japan

GEONET (GPS Earth Observation Network System) and its Prospect

[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...

2004 Volume 50 Issue 2 Pages 53-65
Published: June 25, 2004
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.50.53

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GEONET (GPS Earth Observation Network System), which is a nationwide GPS array and data analysis system of the Geographical Survey Institute, started in 1994. Since then, it has been expanded and improved to monitor crustal deformation of Japanese islands quickly and accurately. Today, it is the densest GPS observation network in the world with 1, 200 GPSbased control stations and some other stations. GEONET has contributed its continuous data to various fields of earth science. In seismo tectonics study, it provided the features of coseismic crustal deformation as well as the steady state crustal deformations by plate motion. Five interplate slow slip events were also found by GEONET and has been playing important role to the recent plate coupling studies. In volcanological study, it provided the sequence of magma activity utilized for the estimation of eruption. GEONET also provided a new measure to detect ionospheric and meteorological signals and have been contributing to atmospheric science. The observed 1 Hz data of almost all stations are now provided to commercial users for positioning services in real time. GEONET is becoming a kind of infrastructure of the locationbased information society. The major present research subjects are improvement of the detectability, development of real-time analysis of crustal deformation, etc. It is also important for the future use of GEONET to maintain observation circumstances properly and to be adapted to the GPS modernization and new GNSSs.

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Gradients of Water Vapor Distribution in the Troposphere Observed with Water Vapor Radiometers in Uji, Southwest Japan

Torao Tanaka, Yoshinobu Hoso, Masatake Harada, Taiichi Hayashi, Ashraf ...

2004 Volume 50 Issue 2 Pages 67-79
Published: June 25, 2004
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.50.67

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Spatial gradients of water vapor distribution in the troposphere cause positioning errors on GPS measurements. If a gradient of water vapor distribution stands for a few days or longer, this will generate biased positioning solutions in that period. Data obtained with two water vapor radiometers (WVR1100^TM by Radiometrics Corporation) in Uji City, Kyoto Prefecture in southwest Japan show that wet delays to the south at elevations of 15°and 10°are generally larger than those to the north and the difference sometimes exceeds 1 and 3 cm, respectively. Similar wet delay gradients are seen in the east-west direction at the same low elevations. In addition the east-west gradient sometimes shows a daily change. Effects of multi-path propagation and radiation from the ground surface, however, cannot be ignored on observations with the radiometers at such low elevations.

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Report of ION National Technical Meeting 2004

Falin Wu

2004 Volume 50 Issue 2 Pages 81
Published: June 25, 2004
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.50.81

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[title in Japanese]

[in Japanese]

2004 Volume 50 Issue 2 Pages 83
Published: June 25, 2004
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.50.83

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NATIONAL REPORT TO THE XXIII GENERALASSEMBLY SAPPORO, JAPAN

THE NATIONAL COMMITTEE FOR GEODESY OF JAPAN, THE GEODETIC SOCIETY OF ...

2004 Volume 50 Issue 2 Pages 89-185
Published: June 25, 2004
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.50.89

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