VGOS VLBI Intensives between MACGO12M and WETTZ13S for the rapid determination of UT1-UTC

TL;DR

This paper reports on a VLBI Intensive program using a novel observation strategy to rapidly determine UT1-UTC with high accuracy, achieving a formal error of 3.1 microseconds in 2022.

Contribution

It introduces a new observation strategy involving rapid elevation scans to improve atmospheric delay estimation in VLBI UT1-UTC measurements.

Findings

25 successful sessions since 2021

Average formal error of 3.1 microseconds in 2022

Performance decline due to technical issues

Abstract

In this work, we present a status update and results of the designated research and development VLBI Intensive program VGOS-INT-S, observed between MACGO12M and WETTZ13S for the rapid determination of the Earth's phase of rotation, expressed via UT1-UTC. The main novelty of these sessions is the use of a special observation strategy, rapidly alternating between high- and low-elevation scans, enabling an improved determination of delays caused by the neutral atmosphere. Since 2021, 25 Intensive sessions have been observed successfully. In early 2022, VGOS-INT-S was among the most accurate Intensive programs with an average formal error $\sigma_{UT1-UTC}$ of 3.1 $\mu$s and a bias w.r.t. IERS C04 of 1.1 $\mu$s. Later, the session performance decreased due to multiple technical difficulties.