Very long baseline interferometry (VLBI) is a geodetic technique capable of deriving the complete set of Earth orientation parameters, including the highly variable Earth’s phase of rotation. This observable can be expressed through UT1–UTC, the difference between the Universal Time and the Coordinated Universal Time. The so-called Intensive sessions, or Intensives, are typically 1-h sessions between two to three stations that are observed daily with the primary goal of determining UT1–UTC with a short latency. In this publication, we examine the impact of erroneous a priori information on the UT1–UTC estimation with VLBI Intensive sessions in a systematic way and on a global scale. Our findings are based on a simulation study which is carried out on a regular \(10 \times 10\) degree grid of artificial telescopes. In the simulations, realistic errors are introduced in the station coordinates, polar motion and nutation to get a global picture of the impact of these errors on the estimation of UT1–UTC. Our results reveal that in contrast to errors in the horizontal components of the station coordinates, an error in the station height only slightly affects the UT1–UTC estimate. North–south-oriented baselines are in general strongly affected by errors in the a priori information. In all cases, very short and very long baselines as well as baselines with a midpoint close to the equatorial plane are less robust. On the other hand, east–west-oriented baselines, except equatorial baselines, seem to be rather resistant against errors of these a priori values.

甚长基线干涉测量 (VLBI) 是一种大地测量技术，能够导出整套地球定向参数，包括高度可变的地球自转相位。该可观测值可以通过 UT1-UTC（世界时与协调世界时之间的差）来表示。所谓的强化会话或强化，通常是每天观察的两到三个站点之间为期 1 小时的会话，其主要目标是确定具有短延迟的 UT1–UTC。在本出版物中，我们通过 VLBI强化课程以系统的方式在全球范围内研究了错误的先验信息对 UT1-UTC 估计的影响。我们的发现基于在人造望远镜的规则“10×10”网格上进行的模拟研究。在模拟中，在台站坐标、极移和章动中引入了实际误差，以全面了解这些误差对 UT1-UTC 估计的影响。我们的结果表明，与台站坐标水平分量的误差相比，台站高度的误差仅对 UT1-UTC 估计产生轻微影响。南北向基线通常会受到先验信息错误的强烈影响。在所有情况下，非常短和非常长的基线以及中点接近赤道面的基线都不太稳健。另一方面，除了赤道基线之外，东西向的基线似乎对这些先验值的错误具有相当的抵抗力。