Earth Planets Space, Vol. 60 (No. 5), pp. e1-e4, 2008E-LETTER
Thomas Hobiger1, Ryuichi Ichikawa1, Tomoji Takasu2, Yasuhiro Koyama1, and Tetsuro Kondo1
1Kashima Space Research Center, National Institute of Information and Communications Technology, 893-1 Hirai, Kashima, Ibaraki 314-8501, Japan
2Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
(Received February 14, 2008; Revised March 24, 2008; Accepted March 28, 2008; Online published May 3, 2008)
Precise satellite orbits and clock information for global navigation satellite systems (GNSS) allow zero-difference position solutions, also known as precise point positioning (PPP) to be calculated. In recent years numerical weather models (NWM) have undergone an improvement of spatial and temporal resolution. This makes them not only useful for the computation of mapping functions but also allows slant troposphere delays from ray-tracing to be obtained. For this study, such ray-traced troposphere corrections have been applied to code and phase observations of 13 sites from the International GNSS Service (IGS) receiver network, which are located inside the boundaries of the Japanese Meteorological Agency (JMA) meso-scale weather model, covering a period of 4 months. The results from this approach are presented together with a comparison to standard PPP processing results. Moreover the advantages and caveats of the introduction of ray-traced slant delays for precise point positioning are discussed.
Key words: GPS, troposphere, ray-tracing, PPP.