ITRFbased

ITRFbased, often written as ITRF-based, refers to systems, datasets, or analyses that use the International Terrestrial Reference Frame (ITRF) as the canonical global reference frame for positions, velocities, and related parameters. In practice, an ITRFbased solution expresses station coordinates as time-dependent quantities tied to a specific ITRF realization (for example ITRF2014 or ITRF2020) and optionally provides Earth orientation and scale information.

Background: The ITRF is an international geodetic reference frame maintained by the International Association of Geodesy (IAG). It integrates observations from GNSS, SLR, VLBI, and DORIS to provide three-dimensional coordinates of stable stations, their velocities to model crustal motion, a global origin, and the global scale, plus Earth orientation parameters.

Implications: ITRFbased approaches enable consistent global data fusion, precise point positioning, and reliable tectonic analyses. Users must note the ITRF realization and epoch; coordinates are given at a reference epoch and may be propagated to other dates using velocities. Transformations to regional frames (for example European ETRS89) require a transformation that is either rigid or time-dependent, incorporating pole-tide and Earth orientation parameter corrections.

Update and usage: Each new ITRF realization improves station positions, velocities, and Earth orientation estimates; datasets and software often label results as ITRFbased to indicate alignment with ITRF rather than a local frame. The term is commonly seen in GNSS processing, geodetic products, and crustal deformation studies.