First Implementation and Evaluation of Five Systems Network RTK

Currently, five navigation satellite systems (BDS-2/BDS-3, GPS, GLONASS, Galileo and QZSS) are broadcasting navigation signals. With more navigation system observations, positioning performance and reliability are expected to be improved. In this study, we developed a software that can provide five systems network RTK augmentation service to users at the first time. A network RTK algorithm that can process five systems observations is proposed. All available observations from different GNSSs are fully used for our software. The characteristics of ambiguity solutions and atmosphere interpolated values for each navigation system are analyzed in detail and the improvement of combined five systems for network RTK performance are carefully evaluated. Firstly, the number of visible satellites of five-system observations are shown. Then, the characteristics of the fractional parts of float wide-lane and narrow-lane ambiguities are analyzed. Except for GLONASS, characteristics of the fractional parts of float extra-wide-lane ambiguities are also analyzed. The modelling accuracy of interpolated ionospheric and tropospheric delays for each navigation system is investigated. Lastly, rover fixing rate and positioning accuracy of combined five systems are computed and evaluated. It is shown that better accuracy and reliability can be obtained for combined five systems, especially when low elevation signals are obscured.