Three technical documents on EGNOS are currently available to developers:
EGNOS Open Service Definition Document Open Service (OS SDD) describes the scope of services provided by the EGNOS Open Service to be used by end-users or Application Specific Service Providers. It details the general conditions relating to the use of the EGNOS service, a technical description of the Signal-in-Space (SIS), the reference receiver, environmental conditions, the service performance achieved and aspects relating to service provision.
The Service Definition Document presents the characteristics and terms and condition of use of the services offered to users by the EGNOS Safety of Life (SoL).
The EGNOS Safety of Life (SoL) Service is provided openly and is freely accessible without any direct charge, and is tailored to safety-critical transport applications in various domains, in particular for aviation applications.
EDAS, the EGNOS Data Access Service, is the third EGNOS service available to users, after the Open Service and the Safety-of-Life Service. Unlike the other two EGNOS services (SoL and OS), EDAS does not provide its products to the users through the EGNOS Signal-In-Space, but throught Internet. EDAS services are oriented to users in different domains of application such as Location Based Services (LBS), Assisted-GNSS (A-GNSS) concepts, a broad range of services in professional GNSS markets, and related R&D activities.