| Earth Observation Mission CFI Software Usage Guide for Object Oriented Software |

# TIME CORRELATION INITIALISATION

The initialisation of the time correlations does not provide any direct functionality to the user, but it is needed for many other operations within the mission planning. The initialisation consist on storing the time correlation between the different allowed time references, (i.e. TAI, UTC, UT1 and GPS time) in TimeCorrelation object. This object is afterwards used for operations such as time tranformations. The time correlation object can be constructed with two different sets of contructors:

- Initialisation from a single or multiple orbit files.
  Orbit files can be provided via filenames or objects from the DataHandling library: OsfFile, OrbitFile, DorisFile, IERSBulletinFile.
- Initialisation from a fixed set of time references.

A complete view of the time reference transformations sequence is presented in following figure:

Please refer also to:

- [MCD] for a detailed description of the time references and formats, coordinate systems, parameters and models used in this document.
- [LIB_SUM] for a more detailed information about the TimeCorrelation class

See an example for the time correlation.