True Real-time Slant Tropospheric Delay Monitoring System with Site Dependent Multipath Filtering

Tetsuya Iwabuchi, Christian Rocken, Akira Wada, Masayuki Kanzak

Abstract:	We have developed a real-time tropospheric slant delay monitoring system for the GPS Earth Observation Network (GEONET [2]) in Japan. The slant delay residual data from May 1, 2010 to August 31, 2011 is used to study the relationship between the variability of the slant delay residuals and precipitation in three historical severe rainfall cases catalogued by the Japan Meteorological Agency (JMA). Site-specific multipath stacking maps are generated every month, and they are applied to raw ionospheric free (IF) post-fit phase residuals to mitigate multipath and site-specific phase center variation (antenna plus radome refraction) errors. We developed the slant tropospheric delay Index (STD index), which is the standard deviation of the residuals normalized to the zenith angle at one epoch. The slant tropospheric delay index showed seasonal variation and diurnal variations, suggesting that it reflects climatology of water vapor variations. We observed a markedly elevated STD index three to four hours prior to the start time of severe rainfall. The STD index decreases suddenly several hours before the end of the severe rainfall. This suggests that the STD index is superior to the zenith tropospheric delay (ZTD) or to precipitable water vapor (PWV) which change rapidly during severe rainfall cases, and that STD index can be used for nowcasting of precipitation, especially as precursor for localized severe rainfall. The current plot of realtime post-fit residuals and PWV from the processing system can be monitored in real-time at http://rtgps.com/slant.php.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	579 - 587
Cite this article:	Iwabuchi, Tetsuya, Rocken, Christian, Wada, Akira, Kanzak, Masayuki, "True Real-time Slant Tropospheric Delay Monitoring System with Site Dependent Multipath Filtering," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 579-587.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In