Advancement in GPS and DGPS

In the process of continuous improvement of my country’s scientific and technological level, the development and application of new technologies are relatively fast, and the application of new technologies in various fields is relatively extensive. The full application of GPS positioning technology in the surveying and mapping line is of great significance, which can greatly improve the efficiency and accuracy of civil engineering surveying. Global Positioning System (GPS) is a highly demanded tool for positioning and synchronization of measurements; therefore, assessing the accuracy of a GPS receiver is an essential phase of any field survey. The main goal of this study is to briefly summarize different commonly used GPS accuracy measures and then compare the horizontal and vertical accuracies of GPS and differential GPS (DGPS) by taking instant measurements, instead of making measurements for long periods of time at sampling locations. To achieve this, a field study was carried out at Middle East Technical University (METU) campus in Ankara, Turkey. As a preliminary step before the field study, a basic sampling strategy was developed. The horizontal and vertical accuracies of both receivers were calculated and given in terms of root-mean-square error (RMSE) and arithmetic mean of error. The results revealed out that DGPS has significantly better performance than GPS, when horizontal and vertical accuracies are considered.