Assessing multiple reference station RTK case study: Southern Ghana
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Date
2009-08-05
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Abstract
The use of RTK methods for surveying purposes have become an efficient way of performing survey tasks around the world. In Ghana however, the RTK surveys are restricted to a few individual private surveyors who carry out such surveys in very restricted base-to-rover distances of a maximum of 8km with a single reference station. The Survey Department of Ghana has
three Continuously Observing Reference Stations (CORS) operated offline from Accra, Takoradi and Kumasi.
The research sought to compare Single Reference Station (SRS) to Multiple Reference Stations (MRS) methods of performing RTK. The comparison was in the form of tests conducted with different SRS located at different locations with base-to-rover distances of between 7-70km. These reference stations were networked to form a MRS and used to evaluate the performance of both methods. The criteria used were the time to fix ambiguity, the number of ambiguity fixed and the reliability of the coordinates computed for either method. The network of reference stations were located in Accra, Dodowa, Asamankese, Suhum, Nsawam and Winneba.
The test results showed that at distances of less than 10km, both SRS and MRS produced comparable results. However at longer base lengths exceeding this limit, the MRS produced markedly superior results. The computed Central Error Probable for the two methods in the tests revealed that the accuracies obtained by the MRS are better for the longer base-to-rover distances. The thesis ends with recommendations for the different owners of CORS in the country to work together to cover a wider area and give better accuracies across the country and also urges the Survey Department of Ghana to work with the universities and other stakeholders to come up with standards for RTK surveys to encourage its proper use.
Description
A Thesis submitted to the Department of Geomatic Engineering Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of Master of Science.