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GPS meteorology: Reducing systematic errors in geodetic estimates for zenith delay
Author(s) -
Fang Peng,
Bevis Michael,
Bock Yehuda,
Gutman Seth,
Wolfe Dan
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl02755
Subject(s) - radiosonde , zenith , geodetic datum , global positioning system , precipitable water , environmental science , radiometer , geodesy , elevation (ballistics) , remote sensing , meteorology , solar zenith angle , water vapor , geography , computer science , mathematics , telecommunications , geometry
Differences between long term precipitable water (PW) time series derived from radiosondes, microwave water vapor radiometers, and GPS stations reveal offsets that are often as much as 1–2 mm PW. All three techniques are thought to suffer from systematic errors of order 1 mm PW. Standard GPS processing algorithms are known to be sensitive to the choice of elevation cutoff angle at this level. We present a processing protocol that is shown to reduce elevation angle dependence in geodetic estimates of zenith delay and, hence, reduce the systematic errors in derived precipitable water. This protocol includes use of the Niell zenith delay mapping functions and International GPS Service phase center models.