A PPP baseline approach for bridge passing

Global Navigation Satellite Systems (GNSS) are increasingly used as the main source of Positioning, Navigation and Timing (PNT) information for inland water navigation. In order to enable automated driving and facilitate driver assistant functions, it becomes of crucial importance to ensure high reliability and accuracy of the GNSS-based navigation solution, especially in challenging environments. One challenging phase of inland waterway navigation is bridge passing which leads to non-line-of-sight (NLOS) effects such as multipath and loss of tracking. This work presents a Precise Point Positioning (PPP) based algorithm in a two-antenna system where one antenna is at the bow and the other is at the stern. Additionally, gyroscope data from an IMU is used. In contrast to a separated position calculation of the two antennas, only one antenna position is estimated and the other is derived from the baseline between the antennas. This allows for accurate positioning even if one antenna does not receive any GNSS measurements. The presented scheme is evaluated using real measurement data from an inland water scenario with multiple bridges. In comparison with a standard PPP scheme as well as an RTK algorithm, the presented approach shows clear advantages in challenging scenarios.