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A simple “geometric” mapping function for the hydrostatic delay at radio frequencies and assessment of its performance
Author(s) -
Foelsche Ulrich,
Kirchengast Gottfried
Publication year - 2002
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 - 10.1029/2001gl013744
Subject(s) - hydrostatic equilibrium , function (biology) , range (aeronautics) , geodesy , elevation (ballistics) , global positioning system , remote sensing , scale height , physics , environmental science , mathematics , geology , computer science , geometry , meteorology , telecommunications , materials science , evolutionary biology , biology , quantum mechanics , composite material
The hydrostatic mapping function, m (ε), describes the dependence of the hydrostatic path delay on the elevation angle ε. We have developed a simple mapping function, where the only free parameter is an “effective height” of the atmosphere, H atm , corresponding to about the first two scale heights above the surface. The value of m (ε) is given by the ratio of the straight‐line ray path length within height H atm to height H atm itself. We used simulated delays at GPS (Global Positioning System) frequencies derived from high resolution ECMWF (European Centre for Medium‐Range Weather Forecasts) atmospheric analysis fields to assess the performance of the “geometric” mapping function relative to well established ones (the Davis, Niell, and Herring mapping functions, respectively). At elevations >6° the new mapping function generally exhibits, based on a single parameter, a performance comparable to or better than the other mapping functions.