*yasuaki kakiage1, satoshi abe1, kazuyuki ohashi1, hideo hamazaki1, kazuyuki tanaka1, satoshi kawamoto1, yuki hatanaka1
(1.GSI of Japan)
Keywords:Geodesy
Geospatial Information Authority of Japan (GSI) has been operating GEONET (GNSS Earth Observation Network System), which involves over 1,300 GNSS stations, since 1996. The daily coordinates for each station are estimated by Bernese GNSS software to monitor the crustal deformation in Japan. The analysis strategy was updated four times. Current version is the fourth generation (4G) analysis, which was developed in 2009. We are now developing a new strategy (5G) because the software, reference frame, and other physical models used in 4G analysis have been obsolete. Major features of 5G analysis are: 1. Update of reference frame, 2. GPS and GLONASS integration, 3. Improvement of the troposphere model, 4. More stable daily coordinates of the reference station (TSUKUBA-1) for analysis. GSI developed 5G prototype in 2017.
The 5G prototype firstly conducts “fix-point analysis” to estimate daily coordinates of TSUKUBA-1. Then all other stations are estimated using GPS and GLONASS data individually. Finally, the GPS and GLONASS solutions are integrated.
The daily coordinates of the TSUKUBA-1 is estimated by a global analysis using worldwide IGS stations under No-Net-Translation constraint. But, we analyzed the data from 1996 to 2004 constraining IGS stations coordinates(SINEX results) directly.
In case of all other GEONET analysis, there is limiting condition to solve combined solution. So we evaluate the combined solutions with respect to limiting condition.
We will show the in detail of fix point analysis and 5G analysis, especially combine solution.