Connecting Geodetic VLBI Telescope Generations at The Ny-Ålesund Geodetic Earth Observatory Through Short-Baseline Interferometry – Final Results

The transition of geodetic Very Long Baseline Interferometry (VLBI) from legacy S/X telescopes to the modern VLBI Global Observing System (VGOS) necessitates careful integration of the new network with existing infrastructure. This presentation will showcase the final results of the NYTIE campaign, conducted at the Ny-Ålesund Geodetic Earth Observatory, where the decommissioning of the legacy S/X telescope NYALES20 was preceded by an extensive short-baseline interferometry campaign to the new VGOS telescopes NYALE13S and NYALE13N. Comparing VLBI results with surveying campaign using total station and GNSS, we find very good agreement in the horizontal components, at the 2-mm level, and slightly less good agreement in the vertical component (up to 8 mm). We find that dedicated measurements, such as NYTIE, give significantly improved results compared to the use of regular IVS-R1 and IVS-R4 sessions for obtaining local-tie information. We assess advantages and limitations for group- and phase-delay results, and we note a significant offset (up to 11 and 23 mm for NYALE13S and NYALE13N, resp.) between the two, also found in the ONTIE project. Lastly, we present our lessons learned from this project with the aim of encouraging other observatories that also host telescopes of both generations to undertake VLBI local-tie measurements.