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Ionospheric bending correction for GNSS radio occultation signals
Author(s) -
Hoque M. M.,
Jakowski N.
Publication year - 2011
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2010rs004583
Subject(s) - radio occultation , ionosphere , gnss applications , total electron content , geodesy , occultation , gps signals , global positioning system , physics , signal (programming language) , remote sensing , geology , satellite , computer science , tec , geophysics , telecommunications , assisted gps , astronomy , programming language
Ionospheric propagation effects on Global Navigation Satellite Systems (GNSS) signals are the most pronounced during radio occultation due to long ionospheric travel paths of the received signal on low Earth orbiting satellites. Inhomogeneous plasma distribution and anisotropy cause higher‐order nonlinear refraction effects on GNSS signals which cannot be fully removed through a linear combination of dual‐frequency observables. In this paper, higher‐order ionospheric effects due to straight line of sight (LOS) propagation assumption such as the excess path length of the signal in addition to the LOS path and the total electron content difference between the curved path and the LOS path have been investigated for selected GPS‐CHAMP occultation events. Based on simulation studies we have derived correction formulas for computing raypath bending effects as functions of signal frequency, tangential height of the raypath, ionospheric parameters such as the maximum ionization and total electron content. If these parameters are known, the proposed correction method is able to correct on an average about 65–80% bending errors of GNSS occultation signals.