Comparative Analysis of GNSS (RTK) and Total Station-Derived Results in Topographical Mapping

The research is on the comparative analysis of GNSS (RTK) and Total Station derived results in the topographic mapping of Campus 3, of Auchi Polytechnic Auchi. The aim is to compare the results obtained using Global Navigational Satellite Systems (Real Time Kinematics) and Total Station Instrument (Co-ordinates mode). The two instruments were used to obtain survey data from the same location, and their topographic plans were produced and compared. A real-time survey was carried out with the Hi-Target GNSS receiver using the slave connected to the CORS Station, which was the base of the GNSS receiver. The slave was used to pick coordinates at all stations around the perimeter and consequently used to survey all the details in the study area. The data obtained by the Hi-Target GNSS receiver was transferred into the computer system via Bluetooth; while the Total Station was used to obtain the coordinates in coordinate mode. The adjusted coordinates and the detailed survey of both the Hi-Target GNSS receiver and the Total Station were plotted using AUTOCAD 2014. The contour lines were created by the use of Surfer 7 software using the data from the two instruments. The results of both methods were compared to get the variations produced by the two methods. The accuracy of the GNSS (RTK) was 1:31000 and that of the Total Station accuracy was 1:29000. It was concluded that the two methods yielded good results in terms of position accuracy with mean differences of 12mm, 13mm and 8mm in Eastings, northings and elevation respectively. It was recommended that either of the methods can be used for topographic surveying however, based on the values of their linear accuracy it can be inferred that, the accuracy obtainable from the data obtained using the GNSS (Hi-Target) instrument is better than that of Total Station instrument. Generally, the two instruments and their methods of data acquisition and processing are within the standard and scope of topographical mapping, therefore they are both suitable for topographical surveying.