Systematic Error Elimination in VGOS for a 1-mm Accurate Terrestrial Reference Frame

Whether we want to monitor global sea level changes or ensure that autonomously navigating cars stay on the road, we must have an accurate and reliable measuring stick – a reference frame – which we measure our coordinates with. Very Long Baseline Interferometry (VLBI) provides the global reference frames needed for this. A new network, the VLBI Global Observing System (VGOS), was created to achieve the 1 mm accuracy in the global reference frame, but systematic errors in instruments, data processing, and modeling still limit performance.

Our project, funded by the Research Council of Finland, investigates these errors using simulations, real observations, and machine learning to understand how they arise and spread. By identifying and classifying them, we lay the foundation for future improvements, enabling ultra-precise reference frames that support science, technology, and society.