As the world moves towards greater levels of autonomy and automation, it is expected that wide-area safety systems and services will become the norm including both terrestrial and GNSS-based safety services. Other major developed economies in the United States/Canada (WAAS), Europe (EGNOS), Japan (MSAS), India (GAGAN), South Korea (KASS), and Australasia (SouthPAN) have now or will soon have access to high-integrity GNSS-enabled aviation procedures, largely implemented via Satellite-Based Augmentation Systems (SBAS).
Currently, the UK does not have access to such services, previously provided via EGNOS, for UK airspace flight operations. In this current situation, it is a priority for the UK to evolve national GNSS capabilities, implementing navigation and timing resilience and integrity, for (a) aviation, (b) maritime, and (c) other growing sectors using GNSS safety applications. As an important first step, there is a need to establish a UKSBAS testbed, broadcasting a GNSS Signal-In-Space (SIS) to begin to address the non-availability of EGNOS safety-of-life services.

The primary objective of the proposed UKSBAS testbed project is to establish rapidly and operate a new national capability utilising current in-orbit Inmarsat geostationary (GEO) satellite assets, a navigation signal generator, associated SBAS data processing and monitoring software from GMVNSL, and use a UK ground station for SIS uplink from Goonhilly Earth Station (GES) to the GEO navigation transponder. The Inmarsat, GMVNSL and GES team has at its immediate disposal all the key assets, technologies and skills necessary to activate such a system in a very short timeframe, no longer than 6 months from Kick-Off to first SIS broadcast. The project will enable performance demonstration activities in support of UK government strategic objectives, including the provision of a first UK Positioning, Navigation and Timing (PNT) SIS. The three primary workstreams of the project, i.e. (a) testbed infrastructure deployment, (b) service demonstrations & performance assessments, (c) maritime integrity service interface developments, will provide for the following results:
► A national SBAS test and development platform available for future use by UK organisations, companies, institutions to test innovative SBAS-delivered PNT services and capabilities.
► The demonstration of service interoperability between UK SBAS and EGNOS across the UK service area.
► The delivery of a UK SIS, which could form the basis for future provision of PNT integrity services for
high-end, regulated users (e.g. aviation, maritime, autonomy/robotics).
► An initial, end-to-end infrastructure to support future prototyping of the delivery of innovative services (i.e. high accuracy, encrypted, alerting, and authentication) to next generation applications and user communities.
► Provisional test results for maritime integrity service concepts based on SBAS data products, by developing and experimenting offline with the use of standard data/message types to generate (offline) modified/bespoke SBAS message types.
► The securing of a PRN code in the range 120-158 to enable on-going use of the test platform by UK
organisations, companies, and institutions in the development of capabilities, applications and services.
► A defined roadmap for the potential evolution of UK SBAS capabilities, services and applications.

The project kicked off on 21-OCT 2021 and will undertake its final review by mid-JULY 2022 with a signal in space broadcast commencing by end-MARCH 2022.