Performance of Network-Based GNSS Positioning Services in Poland: A Case Study

Abstract

Continuously operating reference station (CORS) networks, as one of the fundamental segments of the precise global navigation satellite systems (GNSSs) positioning techniques, have been undergoing rapid development and growth in the last two decades. The existing and newly created CORS networks coincide with both the services provided and the covered area. This is the situation in Poland, where there are five nation-wide and local networks that have in total over 500 stations and provide access to similar GNSS data, real time kinematic (RTK), and network real time kinematic (NRTK) services. This paper presents one of the most comprehensive tests conducted to evaluate the quality of network-based GNSS positioning services performance provided by all CORS networks available in Poland. The test was performed in November 2017 and included the analysis of accuracy and reliability of positioning performance, time to first fix (TTFF), an average age of correction as well as the compliance of the reference frame realization. The test data were obtained from the field measurements of consecutive RTK/NRTK services and simultaneous continuous measurements carried out at 20 reference points of the first-order geodetic network, evenly distributed throughout Poland. Obtained results allowed to estimate the positioning performance accuracy and reliability for all tested streams and their mutual comparison of quality along with the analysis of the reference frame realization compliance implemented by all networks. In most cases, the results confirm the nominal accuracy of positioning (at 68% confidence level) based on tested streams of 1 cm for horizontal and 2 cm for vertical components. However, it was also found that for some networks and streams the obtained accuracy was twice lower (reaching up to 4 cm for the height component), and compliance with the vertical reference frame is lower.