Abstract:
Real-Time Early Warning Systems are a critical approach implemented for monitoring geo-hazard disasters such as earthquakes, tsunamis, volcanic activities, and land subsidence. The Earth's population has experienced a substantial increasement, consequently exposing a growing number of people to the effects of various geo-hazard disasters. These influences could impact citizens and countries at different severity levels, reaching high costs in terms of human beings and economic losses. However, the early warning system's ability to initiate proper and reliable warnings significantly impacts in disaster cost reductions in terms of saving lives, reducing home and infrastructure damages, and mitigating economic losses.
Real-Time Precise Point Positioning (RT-PPP) plays a significant role as part of the Early Warning Systems, due to its potential to provide real-time tracking and global coverage and its reliance on precise real-time measurements acquired from only one receiver. However, the RT-PPP approach applies State Space Representation (SSR) products that are highly sensitive to several GNSS error sources. As a result, the warning system's availability and reliability are negatively impacted. It may even be triggered to issue false warnings by factors such as long initialization times, convergence losses, due to poor quality of orbital and clock corrections, ambiguity resolutions, or/and multipath error. Furthermore, poor satellite geometry and the latency of SSR products severely affect the performance of real-time PPP positioning.
