An Architecture for Seamless Handover of PPP-RTK Corrections Across Redundant Networks

Precise point positioning real-time kinematics (PPP-RTK) service operators generally utilize a redundant reference station network to ensure operational resilience. These redundant networks share identical geometry but use distinct receivers and antennas. Although atmospheric and satellite delays, such as clock, code, and phase biases, should theoretically be identical, practical discrepancies arise due to hardware biases and ambiguities between the receivers in the two networks. This leads to differences in the estimable parameters for common satellite and atmospheric delay components. Therefore, this paper presents a seamless handover algorithm for PPP-RTK corrections across redundant networks. In this study, IGS ultra-rapid precise orbits were utilized, and the common-view technique was applied using dual-frequency code and carrier phase observations from the Global Positioning System (GPS) single constellation. The proposed architecture continuously estimates the inter-network offset between redundant networks. When a handover between redundant networks occurs, the estimated inter-network offset is compensated before broadcasting. The proposed architecture facilitates the resilient provision of PPP-RTK corrections even during handovers across redundant networks, thereby eliminating the need for users to re-estimate ambiguities and ensuring seamless positioning performance. To evaluate the performance of the architecture, two redundant PPP-RTK networks were configured using continuously observed reference stations (CORS) in South Korea. Finally, the feasibility of the leveling process and its positioning performance were evaluated.