The primary goal of the geodetic Very Long Baseline Interferometry (VLBI) technique is to provide highly accurate terrestrial and celestial reference frames as well as Earth orientation parameters. In compliance with the concept of VLBI, additional parameters reflecting relative offsets and variations of the atomic clocks of the radio telescopes have to be estimated. In addition, reality shows that in many cases significant offsets appear in the observed group delays for individual baselines which have to be compensated for by estimating so-called baseline-dependent clock offsets (BCOs). For the first time, we systematically investigate the impact of BCOs to stress their importance for all kinds of VLBI data analyses. For our investigations, we concentrate on analyzing data from both legacy networks of the CONT17 campaign. Various aspects of BCOs including their impact on the estimates of geodetically important parameters, such as station coordinates and Earth orientation parameters, are investigated. In addition, some of the theory behind the BCO determination, e.g., the impact of changing the reference clock in the observing network on the BCO estimate is introduced together with the relationship between BCOs and triangle delay closures. In conclusion, missing channels, and here in particular at S band, affecting the ionospheric delay calibration, are identified to be the dominant cause for the occurrence of significant BCOs in VLBI data analysis.

大地测量甚长基线干涉 (VLBI) 技术的主要目标是提供高度准确的地球和天体参考系以及地球方向参数。根据VLBI的概念，必须估计反映射电望远镜原子钟相对偏移和变化的附加参数。此外，现实表明，在许多情况下，观察到的单个基线的群延迟中会出现显着的偏移，必须通过估计所谓的与基线相关的时钟偏移 (BCO) 来补偿这些偏移。我们第一次系统地调查了 BCO 的影响，以强调它们对各种 VLBI 数据分析的重要性。对于我们的调查，我们专注于分析来自 CONT17 活动的两个旧网络的数据。研究了 BCO 的各个方面，包括它们对大地测量重要参数（例如站坐标和地球方向参数）估计的影响。此外，还介绍了 BCO 确定背后的一些理论，例如改变观测网络中参考时钟对 BCO 估计的影响，以及 BCO 和三角延迟闭合之间的关系。总之，丢失信道，特别是在 S 波段，影响电离层延迟校准，被认为是 VLBI 数据分析中出现显着 BCO 的主要原因。例如，改变观测网络中的参考时钟对 BCO 估计的影响与 BCO 和三角延迟闭合之间的关系一起介绍。总之，丢失信道，特别是在 S 波段，影响电离层延迟校准，被认为是 VLBI 数据分析中出现显着 BCO 的主要原因。例如，改变观测网络中的参考时钟对 BCO 估计的影响与 BCO 和三角延迟闭合之间的关系一起介绍。总之，丢失信道，特别是在 S 波段，影响电离层延迟校准，被认为是 VLBI 数据分析中出现显着 BCO 的主要原因。