"The IR component of an ADIRU gives attitude, flight path vector, ground speed and positional data. The ring laser gyroscope is a core enabling technology in the system, and is used together with accelerometers, GPS and other sensors to provide raw data. "
The FMC may be supplied by other manufacturers than Honeywell. The ADIRU data is available, whether it is used or not, is dependent on the box. You can have a Smiths, or Thales box with the Honeywell ADIRU, they may integrate the raw data or not.
In designing RNP and GBAS procedures, the update and drift rates are a significant part of the calculations.
This ADIRU IS GPS updated.