Accuracy assessment of VRS in a dynamic environment

Abstract

The Virtual Reference Station (VRS) concept is one method that is being employed around the world to overcome some of the limitations with conventional Real Time Kinematic (RTK) positioning. There has been an increasing amount of research into the accuracy of VRS RTK GPS measurements, and the Department of Natural Resources and Water has identified the need to investigate the use of VRS in a dynamic environment. This project has compared the accuracy, precision and latency of conventional RTK and VRS RTK GPS measurements taken in a dynamic environment. This gives an insight into the suitability of the VRS RTK GPS system to real time dynamic applications. The testing regime used for this project involved attaching RTK GPS equipment to a trolley and positioning reference marks (a series of stakes with barcodes attached) adjacent to a pathway. As the trolley passes these reference marks, a barcode reader on the trolley will scan the barcodes and will initiate a GPS measurement for both conventional RTK and VRS RTK methods. These measurements are compared to the true locations of the reference marks to determine the accuracy, precision and latency. The results show that the VRS RTK method may be suitable for real time dynamic applications such as machine guidance. However this testing has resembled only slow speed dynamic applications in the range of 1-5 km/h. Further testing would be required for faster speeds.