The Earth Orientation Parameters (EOP) are the parameters representing the rotational part of the transformation between the current releases of the International Celestial Reference Frame (ICRF) and the International Terrestrial Reference Frame (ITRF). Accordingly, the EOP describe the change of the orientation of the Earth’s surface, on which the observatories are located, with respect to a space fixed reference frame. Earth rotation refers to the solid Earth component of the dynamic Earth system excluding deformations, such as tides and continental drift. Through interactions of individual components, angular momentum can be transferred between the atmosphere, ocean, and solid Earth, or between the Earth’s core and mantle due to the coupling mechanisms.
The following examples give an overview of the relevance of the knowledge of accurate Earth orientation parameters:
- Realization of reference frames on Earth and in space
- Precise positioning and satellite navigation
- Precise orbit determination (POD)
- Realization of time systems (e.g. monitoring of the duration of days)
- Earth system studies (e.g. climate change)