Tropospheric delay modeling is challenging in high-precision Very Long Baseline Interferometry (VLBI) analysis due to the rapid water vapor variation and imperfect observation geometry, where observations from Global Navigation Satellite Systems (GNSS) co-locations can enhance the VLBI analysis. We investigate the impact of tropospheric ties in the VLBI and GNSS integrated processing during the CONT05–CONT17 campaigns, and present a method that automatically handles the systematic tropospheric tie biases. Applying tropospheric ties at VLBI–GNSS co-locations enhances the observation geometry and improves the solution reliability. The VLBI network is stabilized, with station coordinate repeatability improved by 12% horizontally and by 28% vertically, and the network scale improved by 32%. The Earth Orientation Parameters (EOP) improve by up to 20%. Both zenith delay and gradient ties contribute to the improvement of EOP, whereas the gradient ties contribute mainly to the improvement of length of day and celestial pole offsets.

由于快速的水汽变化和不完善的观测几何结构，对流层延迟建模在高精度超长基线干涉测量 (VLBI) 分析中具有挑战性，其中来自全球导航卫星系统 (GNSS) 共址的观测可以增强 VLBI 分析。我们研究了 CONT05-CONT17 活动期间对流层关系对 VLBI 和 GNSS 综合处理的影响，并提出了一种自动处理系统对流层关系偏差的方法。在 VLBI-GNSS 共址处应用对流层关系增强了观测几何并提高了解决方案的可靠性。VLBI网络稳定，站坐标重复性水平提高12%，垂直提高28%，网络规模提高32%。地球方位参数 (EOP) 提高了 20%。