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Lookup NU author(s): Dr Liz Petrie, Professor Matt King, Professor Philip Moore, Dr David Lavallee
This study provides a first attempt at quantifying potential signal bending effects on the GPS reference frame, coordinates and zenith tropospheric delays (ZTDs). To do this, we homogeneously reanalysed data from a global network of GPS sites spanning 14 years (1995.0-2009.0). Satellite, Earth orientation, tropospheric and ground station coordinate parameters were all estimated. We tested the effect of geometric bending and dTEC bending corrections, which were modelled at the observation level based, in part, on parameters from the International Reference Ionosphere 2007 model. Combined, the two bending corrections appear to have a minimal effect on site coordinates and ZTDs except for low latitude sites. Considering five days (DOY 301-305, 28 October-1 November 2001) near ionospheric maximum in detail, they affect mean ZTDs by up to similar to 1.7 mm at low latitudes, reducing to negligible levels at high latitudes. Examining the effect on coordinates in terms of power-spectra revealed the difference to be almost entirely white noise, with noise amplitude ranging from 0.3 mm (high latitudes) to 2.4 mm (low latitudes). The limited effect on station coordinates is probably due to the similarity in the elevation dependence of the bending term with that of tropospheric mapping functions. The smoothed z-translation from the GPS reference frame to ITRF2005 changes by less than 2 mm, though the effect combines positively with that from the second order ionospheric refractive index term. We conclude that, at the present time, and for most practical purposes, the geometric and dTEC bending corrections are probably negligible at current GPS/reference frame precisions.
Author(s): Petrie EJ, King MA, Moore P, Lavallee DA
Publication type: Article
Publication status: Published
Journal: Journal of Geodesy
Year: 2010
Volume: 84
Issue: 8
Pages: 491-499
Date deposited: 24/09/2012
ISSN (print): 0949-7714
ISSN (electronic): 1432-1394
Publisher: Springer
URL: http://dx.doi.org/10.1007/s00190-010-0386-2
DOI: 10.1007/s00190-010-0386-2
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