Global Navigation Satellite System (GNSS) Supported Services

This page provides guidance to Air Traffic Service (ATS) Providers wishing to implement Instrument Approach Procedures supported by the Global Navigation Satellite System (GNSS).

The following information is in support of CAP 670, Part C, Section 2, NAV 07 ATS Requirements for RNAV(GNSS) Instrument Approach Procedures.

Safety Assessment

When implementing new services it is necessary for an Air Navigation Service Provider (ANSP) to make a safety assessment taking into account various factors that may impact the safety of that service. Not all of the relevant factors that support the service may be within the direct managerial control of the service provider, but the provider must be aware of the influence they may have on the service.

GPS is one such system where the supporting infrastructure is outside the control of the service provider yet its performance needs to be considered in making an assessment of the safety of the service provided.  CAA guidance material shows how the EU Common Requirements are applicable to GNSS supported services.

European regulations also require an ANSP providing an Instrument Approach Procedure supported by EGNOS to have an agreement with the European Satellite Services Provider (ESSP) as supplier of the EGNOS Service. The ESSP may be contacted at

Compliance with ICAO Annex 10 Standards and Recommended Practices (ICAO SARPS)

Guidance is available on the assessment of compliance with the ICAO Annex 10 Volume 1 GNSS Signal in Space (SiS) performance requirements for the following services:

Monitoring reports are available to allow ANSPs to assess the performance of the appropriate GNSS SiS for these approach types:

Change Notification

CAP 670 Part A, paragraphs A88 to A93 'Change Notification Requirements'.

Related Publications

CAP 670, Part C, Section 2, NAV 07 ATS Requirements for RNAV(GNSS) Instrument Approach Procedures
CAP 413 Radio telephony Manual, Chapter 6 Approach Phraseology
CAP 493 Manual of Air Traffic Services (MATS) Part 1, Section 3 Approach Services 
ESSP Website

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