Comparison of Galileo HAS and PPP-RTK in an inland waterway scenario

Kurzfassung

Global Navigation Satellite Systems (GNSS) are the main enabler for position, navigation and timing (PNT) data, especially in the mode of inland waterway transport. The former can be challenging due to non-line-of-sight (NLOS) and signal blockage on structures such as bridges, waterway locks and port infrastructure. Positioning algorithms using only code observations are the de facto standard but their precision make them incompatible with driver assistance systems or autonomous driving. Instead, phasebased positioning is a necessity to enable decimetre-level accuracy with algorithms such as Real Time Kinematic (RTK) or Precise Point Positioning (PPP). While RTK allows for almost instantaneous horizontal positioning accuracy of a couple a centimetres, it requires having a GNSS base station nearby and a two-way connection between user and base station. On the other hand, PPP does not require a two-way connection but it needs at least some minutes to converge to the desired accuracy. In recent years, a hybrid solution called PPP-RTK, i.e. a PPP solution that integrates real-time high precision navigation data and regional atmospheric corrections, has gained momentum, especially with the release of the Galileo High Accuracy Service (HAS). In this paper, we investigate PPP-RTK using the German-wide station network from Satellitenpositionierungsdienst der Deutschen Landesvermessung (SAPOS) as well as the Galileo High Accuracy Service which can be received on a global scale. We test both services on an inland waterway scenario, analyzing both the position accuracy in opensky conditions and the convergence time after challenging phases, such as bridge passing where the satellite signals need to be re-acquired.