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Volume 47 (2001)
- Issue 4 Pages 755-
- Issue 3 Pages 701-
- Issue 2 Pages 629-
- Issue 1 Pages 1-
Volume 47, Issue 4
Displaying 1-4 of 4 articles from this issue
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Tetsuya Iwabuchi, Katsushi Chida, Isao Naito2001 Volume 47 Issue 4 Pages 755-772
Published: December 25, 2001
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe relationship between up-down (UD) component of the site coordinates and zenith tropospheric delay (ZTD) is studied by using the correlation analysis method and the principal component analysis method for the purpose of developing techniques to separate vertical coordinates and zenith tropospheric delay more strictly in GPS analysis. The data set used in the study is the solutions of the routine analysis for GSI / GEENET (Geographical Survey Institute/GPS Earth Observation NETwork) with the Bernese GPS software. The two periods in the summer and winter of 1996; from August 8 to September 28 and from October 31 toDecember 30, are selected because continuous data set is available in the two periods. The daily anomalies in UD and ZTD (UD anomaly and ZTD anomaly) from their averaged values are used in the analyses. The strong positive or negative correlation coefficients between UDand ZTD- anomalies can be seen in many sites when the length of the data is 3 to 5 days. Also, the strong correlation coefficients are remained in some parts when the length of the data is longer than 17 days. The spatial patterns of the correlation coefficients with the data length of 9 days are almost steady in summer, while they change with 10-day scale in winter. Some of the patterns are similar to a spatial pattern of clustering structure applied for the GEONET routine analysis. The empirical orthogonal functions (EOF) for the first principal components (PC) in UD- and ZTD- anomalies correspond to the temporal change of the averaged values for all the sites in their anomalies. The EOFs for the second and third PC show common northsouth or east-west oscillation patterns over the Japanese Islands, which may correspond to weather variations over the islands. The spatial pattern of EOFs for UD anomalies shows similar spatial pattern to the clustering structure. These results suggest that changes in UD (site coordinate) are strongly affected by ZTD changes, corresponding to water vapor variations. However, some biases affected by cluster organizations in the GEONET routine nalysis areseen in the correlation maps and EOFs. It is thus necessary to re-analyze GEONET data with other methods such as precise point positioning that can avoid the clustering effects.View full abstractDownload PDF (6423K) -
Wataru Morii2001 Volume 47 Issue 4 Pages 773-786
Published: December 25, 2001
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSWe attempted to explain temperature changes in an observation tunnel on the basis of the barometer records, in order to avoid bad effects caused by the slow response characteristic of the quartz thermometer. Taking into account adiabatic expansion of the air and heat release (or absorption) in the air from the wall surface of the tunnel, we evaluated temperature changes in the observation tunnel. Temperature changes of diurnal and semi-diurnal were successfully evaluated from the barometer records. Pulsive and oscillational temperature changes of short periods were also reproduced, using the barometer records . Temperature changes in the period range from 10 minutes to 24 hours were successfully evaluated on thebasis of the barometer records. Moreover, we showed a possibility that correction of extensometer records for effects of thermal expansion worked well using barometer records rather than using thermometer records.View full abstractDownload PDF (1315K) -
Hiroshi Masaharu2001 Volume 47 Issue 4 Pages 787-797
Published: December 25, 2001
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSMethods using mathematics software Mathematica for deriving series expansion formula for obtaining latitude from meridian arc length are presented. Two formulas given in Literatures are derived with the software and the accuracy is checked. From the result, it is recommended to use these series expansion formula instead of iteration methods such as Vewton method.View full abstractDownload PDF (997K) -
Hiroshi Takiguchi, Yoichi Fukuda2001 Volume 47 Issue 4 Pages 799-802
Published: December 25, 2001
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSWe investigated scattering of the GPS site coor dinates and baseline length changes using daily GEONET solutions. We first calculated baseline length changes from the daily coordinates, and then calculated their standard deviations every tendays. The standard deviations, which are small in winter and large in summer, clearly show seasonal variations. Another characteristics is that the standard deviations are dependent on the baseline length. These facts suggested that uncorrected water vapor effects affected on the accuracy of the GEONET solutions. The standard deviations of both baseline length and ellipsoidal height show some dependency on the GEONET station IDs, which are related to the year of establishment and the region of the sites. The standard deviations before 1996 are larger than those after 1996. Theyare small near Tsukuba, and are generally large in western Japan compared with eastern Japan. Spatial pattern of the standard deviations at the sites of Trimble receivers seems to have a relation with the regional administration boundaries. This may suggest that environments of observation points or differences of the installation methods affect on the accuracy.View full abstractDownload PDF (2572K)
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