The Galileo Timing Receiver: Definition of Requirements and Related Test Procedures in Support of Standardization

The Global Navigation Satellite System (GNSS) provides accurate timing and synchronization for critical infrastructures such as telecommunications, power grids, financial systems, and transportation networks. In this context, Galileo is working on the implementation of a Timing Service. The Service aims at improving significantly the Timing and Synchronization performance of the System. The Service will also add a monitoring layer that will generate a dedicated message – the Timing Service Message (TSM) - to ensure a high level of trust to the users. Finally, another key pillar of the Galileo Timing Service concept is the trust on the Timing Receivers themselves. This will be ensured through the compliance of Galileo receivers to a new Galileo Timing Receiver Standard. The Galileo Timing Receiver Standard, developed under CEN/CENELEC JTC5, has completed all the relevant review milestones and it is expected to be formally published as a European standard by the end of 2024, available under the designation number EN16605. The Standard defines the functional and performance requirements and associated tests for the Galileo Timing Receiver. This paper describes the JRC contributions to the Standard. It comprises how key requirements were derived, as well as the test procedures to validate the receiver against the standard. It starts by addressing key requirements for the receiver to meet the demanded accuracy and integrity. This includes a comprehensive analysis of the nominal errors affecting the timing solution. The paper then focuses on the derivation of key requirements, assessed both analytically and through ad-hoc tests with commercial timing receivers. Finally, the paper provides the derivation and justification of the test procedures included in the standard, with particular emphasis on the TRAIM tests.