CORSnet-NSW network RTK: Same look and feel... only better

CORSnet-NSW is a rapidly growing network of Global Navigation Satellite System (GNSS) Continuously Operating Reference Stations (CORS) providing fundamental positioning infrastructure for New South Wales that is accurate, reliable and easy to use. This positioning infrastructure supports a wide range of GNSS applications in areas such as surveying, agriculture, mining and construction. This paper presents the current status of CORSnet-NSW and briefly outlines the difference between the traditional, single-base Real Time Kinematic (RTK) and the Network RTK (NRTK) approaches. Initial results from some of the extensive testing of NRTK performance undertaken by LPI across eastern NSW are then presented. These tests have shown that while NRTK has the same 'look and feel' as single-base RTK, it produces superior coordinate results in regards to both precision (i.e. repeatability) and accuracy (i.e. agreement with the State's survey ground control network). The benefit of averaging observations over a 1-minute window and re-occupying points 20-40 minutes later is illustrated. It is also shown that coordinate quality (CQ) indicators provided by the GNSS rover equipment are often overly optimistic, even under favourable satellite visibility and multipath conditions, and should therefore be used with caution.