A Web-Based Real-Time Monitoring System for GNSS Data Quality and Integrity

The single base real-time kinematic (RTK) positioning technique is distance-dependent in terms of accuracy and reliability of the integer ambiguity resolution. The Network RTK (NRTK) technique has been developed to overcome this limitation, so is able to be used over longer distances than is possible with single base RTK whilst maintaining centimetre-level accuracy. This multiple reference station approach provides a precise measurement correction to the RTK positions over long baselines by interpolating errors across the reference receiver network. In order to provide reliable corrections it is necessary for the NRTK service provider to have quality and integrity monitoring mechanisms. The Department of Lands, New South Wales, operates a network of Continuously Operating Reference Stations (CORS) called ‘SydNET ’ around the city of Sydney to provide real-time GPS data via the internet. It is, however, difficult to predict the variation in performance and the status of the reference stations. Therefore a scheme to monitor data streams in real-time has been proposed for dealing with the data quality control issue. This paper presents a Web-based scheme for monitoring real-time Global Navigation Satellite System (GNSS) data streams from the SydNET stations. In order to demonstrate th