This release is the follow-up to a preliminary document that was issued in 2015 for public consultation, and incorporates numerous improvements suggested by the user community.

This document complements the Galileo Open Service Signal-In-Space Interface Control Document (OS SIS ICD v1.2, 2015) by describing the encoding and use of the Signal-In-Space (SIS) Status for the Galileo Open Service (OS).

The SIS Status (i.e. the operational status of the OS SIS broadcast by each of the Galileo satellites) determines the applicability of the minimum performance level of services defined in the Galileo Open Service – Service Definition Document (OS SDD, to be published later this year).

The content of the OS SIS OSD is specifically targeted towards manufacturers of Galileo receivers, as a guide to the use of the various SIS health indicators for implementation of robust navigation systems.