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The effect of the second order GPS ionospheric correction on receiver positions
Author(s) -
Kedar S.,
Hajj G. A.,
Wilson B. D.,
Heflin M. B.
Publication year - 2003
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 - 10.1029/2003gl017639
Subject(s) - ionosphere , global positioning system , geodesy , oscillation (cell signaling) , gps signals , earth's magnetic field , faraday effect , total electron content , physics , earth's rotation , position (finance) , geology , geophysics , tec , magnetic field , assisted gps , computer science , telecommunications , finance , quantum mechanics , biology , economics , genetics
The Global Positioning System (GPS) transmits two frequencies, allowing users to correct for the first‐order ionospheric signal group delay (or phase advance) of 1–50 m. The second‐order ionospheric term, caused by the Faraday rotation effect induced by the Earth magnetic field, is about 1000 times smaller and usually ignored. In this study, we implement the 2nd‐order correction suggested by Bassiri and Hajj [1993] and investigate its effect on GPS‐inferred station positions. The correction causes a latitude dependent ∼0.1–0.5 cm southward shift to the position which is roughly proportional to the integrated electron density above the receiver, and has strong diurnal, seasonal and decadal signatures. By analyzing a three‐year time series of equatorial station positions obtained without the 2nd‐order correction, a strong semi‐annual north‐south oscillation is observed, the origin of which has not been hitherto explained. We verify that this apparent oscillation can be largely removed once the 2nd‐order correction is applied.