A United Kingdom Space-Based Augmentation System Testbed Capability

David Hill, George Newton, Claudio Soddu, Mark Dumville, Madeleine Easom, Smita Tiwari, William Roberts, Julián Barrios Lerma, José Gabriel Pericacho, Chris Emes

Abstract:	The United Kingdom (UK) withdrawal from the European Union (EU) affected the way that the UK participates in EU Space Programs. In the context of Space-Based Augmentation Systems (SBAS), this event ended UK participation in the EGNOS program and prevented the use of EGNOS Safety of Life (SOL) services in UK airspace as from June 25th, 2021. Following this, a new UK national SBAS demonstrator was established, to aid in assessing the options for future operational SBAS capabilities. This is the “UKSBAS Testbed”, developed under the European Space Agency’s “Positioning, Navigation and Timing: Innovation, Competitiveness and Support for Institutional Projects” (NAVISP) program. The project is led by Inmarsat, with support from GMV NSL and Goonhilly Earth Station. The UKSBAS Testbed uses a currently in-orbit Inmarsat geostationary (GEO) satellite navigation transponder, a commercial-off-the-shelf navigation signal generator, SBAS message generation, Message Type 0 (MT0) checks and service performance monitoring capabilities, and a UK ground station at Goonhilly for the signal uplink to the GEO navigation transponder. The testbed architecture uses a dense network of existing Continuously Operating Reference Stations (CORS) made available by UK Ordnance Survey and IGS real time services as sources of GPS observations and navigation data. A primary objective of the testbed is to establish a UK SBAS L1 test Signal in Space (SIS) that may form the basis for the provision of a future SBAS services. The test signal is marked as being not operational (and therefore not to be used for any safety-critical applications) through the regular transmission of SBAS Message Type 0 (MT0) in compliance with ICAO SARPS. The testbed enables the assessment of the interoperability between UK SBAS and EGNOS signals within their respective coverage areas. A further objective is the delivery of system performance assessments in relation to the monitoring of GPS via the dense, high-redundancy CORS network. Finally, the infrastructure includes a performance monitoring platform able to compute the system performances not only in terms of aviation services (e.g., APV-I, LPV-200 availability) but also at user level (e.g., performances at dedicated CORS stations). The uksbas.org website provides live information on the performance of the UKSBAS Testbed.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	714 - 724
Cite this article:	Hill, David, Newton, George, Soddu, Claudio, Dumville, Mark, Easom, Madeleine, Tiwari, Smita, Roberts, William, Lerma, Julián Barrios, Pericacho, José Gabriel, Emes, Chris, "A United Kingdom Space-Based Augmentation System Testbed Capability," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 714-724. https://doi.org/10.33012/2022.18406
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