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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/9426

Title: The impact of different tropospheric models on GPS baselines in Ghana
Authors: Atta–Osei, Emmanuel
Issue Date: 27-Oct-2016
Abstract: The ionosphere and the troposphere are the two main layers in the atmosphere which delays GPS signals. Unlike the tropospheric bias, the ionospheric bias can be mitigated using dual frequency GPS receivers. Compensation for the tropospheric delays however requires a standard tropospheric model to be applied. Several tropospheric models are incorporated in commercial GPS processing software, including Trimble Geomatics Office (TGO), for correcting tropospheric delays. To investigate the impact of the different standard tropospheric models in TGO on GPS baselines so as to determine the best model for use by surveyors in Ghana, two simultaneous 24 hour observations were carried out at four selected COR stations in the Golden Triangle of Ghana. The RMS errors of the coordinates of the COR stations yielded by the five standard tropospheric models tested were 0.0287m for Saastamoinen and Hopfield models, 0.0297m for the Goad-Goodman model and 0.0317m for both the Niell and Black models. The RMS errors from all the models passed the USACE criteria of 0.04m for long baselines beyond 100km. However, whenever a tropospheric model was ignored in the baseline processing, the RMS error was more than three times greater than the 0.04m accuracy limit. Surveyors must therefore avoid processing GPS baselines without tropospheric models. In conclusion, any of the five models evaluated in this study can perform well in the study area. Nevertheless, the choice of either the Hopfield or the Saastamoinen models is optimum for the processing of baselines in Ghana.
Description: A thesis submitted to Department of Geomatic Engineering Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Science in Geomatics Engineering, 2016
URI: http://hdl.handle.net/123456789/9426
Appears in Collections:College of Engineering

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