| Network Real-Time Kinematic (RTK) has become popular in the past decade as an efficient method of precise, real-time positioning. Its relatively low cost and ease-of-use makes it a good candidate to replace static relative Global Positioning System (GPS) in, e.g., land surveying. A lack of previous studies aroused the interest of the Ministry of Transportation of Ontario (MTO) to request York University to complete a comprehensive study of the performance of network RTK in southern Ontario and whether it is a suitable method for MTO control surveying. Extensive fieldwork campaigns in the winter of 2010 and summer of 2011 were carried out and ∼300 hours of static and ∼50 hours of kinematic network RTK data were collected from three different service providers. A set of metrics were defined to characterize the performance of network RTK: availability, time-to-first-fix, precision, accuracy, solution integrity and moving average filtering. The data were used to characterize the horizontal performance of network RTK services and the results along with a set of guidelines and specifications were provided (Saeidi et al., 2011; Bisnath et al., 2012). This thesis presents the horizontal network RTK performance evaluation, as well as the vertical and kinematic performance. The aforementioned metrics are used to evaluate the quality of network RTK in southern Ontario, and to compare to similar services available in other locations. The result have revealed expected ∼2-3 cm (95%) precision for the horizontal and vertical components; however, large horizontal and vertical biases were observed, which can be as high as 4 cm. The solution integrity has shown that typically, 3σ solution uncertainties are larger than the actual errors, unless large biases exist. Moving average filtering has confirmed that due to large outliers and spikes in the solutions, 1 second observation periods are not sufficient to provide a precise solution; larger observation windows should be used, e.g., 5 minutes, to reduce the magnitude of maximum errors. The kinematic analysis has revealed issues with synchronization and timing between different data sets. Also, low solution availability while using the network RTK in kinematic mode is seen throughout the results. Overall, network RTK service performance in southern Ontario is slightly lower than the norm reported from similar services in other places. |
