Although modern global geometric reference frames (GRFs) such as the International Terrestrial Reference Frame (ITRF) can be used anywhere on Earth, regional reference frames (RRFs) are still used to densify geodetic control and optimize solutions for continental-scale areas and national purposes. Such RRFs can be formed by densifying the ITRF, utilizing GPS / GNSS stations common to both the ITRF and the RRF. It is possible to attach a RRF to a GRF by ensuring that some or all of the coefficients of the trajectory models in the RRF are ‘inherited’ from the trajectory models that define the GRF. This can be done on an epoch-by-epoch basis, or (our preference) via transformations that operate simultaneously in space and time. This paper documents inconsistencies in the densification of ITRF that arise when the common stations’ trajectory models ignore periodic displacements. This results in periodic coordinate biases in the RRF. We describe a generalized procedure to minimize this inconsistency when realizing any RRF aligned to the ITRF or any other ‘primary’ frame. We show the method used to realize the Argentine national frame Posiciones Geodésicas Argentinas (POSGAR) and discuss our results. Discrepancies in the periodic motion amplitudes in the vertical were reduced from 4 mm to less than 1 mm for multiple stations after applying our technique. We also propose adopting object-oriented programming terminology to describe the relationship between different reference frames, such as a regional and a global frame. This terminology assists in describing and understanding the hierarchy in geodetic reference frames.

尽管现代全球几何参考框架 (GRF)，如国际陆地参考框架 (ITRF) 可以在地球上的任何地方使用，但区域参考框架 (RRF) 仍用于加强大地测量控制并优化大陆尺度区域和国家目的的解决方案. 这样的 RRF 可以通过使用 ITRF 和 RRF 共有的 GPS/GNSS 站来增密 ITRF 来形成。通过确保 RRF 中的轨迹模型的部分或全部系数从定义 GRF 的轨迹模型“继承”，可以将 RRF 附加到 GRF。这可以在逐个时代的基础上完成，或者（我们的偏好）通过在空间和时间上同时运行的转换来完成。本文记录了当公共台站的轨迹模型忽略周期性位移时出现的 ITRF 致密化的不一致。这导致 RRF 中的周期性坐标偏差。当实现与 ITRF 或任何其他“主要”框架对齐的任何 RRF 时，我们描述了一个通用过程以最小化这种不一致。我们展示了用于实现阿根廷国家框架的方法Posiciones Geodésicas Argentinas (POSGAR) 并讨论我们的结果。应用我们的技术后，多个站点的垂直周期运动幅度的差异从 4 mm 减少到小于 1 mm。我们还建议采用面向对象的编程术语来描述不同参考框架之间的关系，例如区域框架和全局框架。该术语有助于描述和理解大地参考系中的层次结构。