A Pseudolite-Based Maritime Navigation System: Concept through to Demonstration

Abstract

GPS alone will be unable to meet emerging performance requirements for maritime applications with respect to service robustness, accuracy, integrity and availability. Even when Galileo (or indeed other nascent GNSS) eventually become operational there will be performance gaps. In particular, identified applications in port areas (for example automated docking) and in inland waterways, have very stringent performance requirements. EADS Astrium Ltd has developed a Test Environment for a Maritime Navigation System in order to perform demonstrations for the maritime community. This includes a number of Transmit Stations mounted on existing structures and terrain at accurately known locations overlooking a navigation zone (such as a maritime harbour). These continuously transmit replica GNSS signals. Another key component of the Navigation System is the single Monitoring and Control Station. This monitors each transmitter’s signal, calculates clock corrections and provides each Transmit Station with the contents of its navigation messages, emulating the function of the Galileo central control facility. It also controls and monitors any demonstration signal scenarios. This paper presents details of Astrium’s Pseudolite-based Navigation System that is the foundation of a Maritime Test Environment. As well as design details, the paper presents outcomes from a public demonstration undertaken in Oban, on the West Coast of Scotland in March 2008.