Global Navigation Satellite Systems (GNSS), including European Galileo and EGNOS, are the underpinnings of the modern Positioning Navigation and Timing (PNT) systems. They offer time and position 24h/7d across the globe. 

The European Radio Navigation Plan (ERNP) estimates that over 10% of European GDP is enabled by economic activities underpinned by GNSS through sectors such as transport (air, sea, and road), industry (telecom, energy, financial), agriculture, fisheries, as well as security and defence.

Despite its technological excellence, GNSS can be subject to local (jamming/interference) or global (space weather, system fault) outage. Its service is also limited in areas of poor sky visibility. Given then GNSS critical role, it is important to also utilize other PNT (position, navigation, and time) systems, addressing those gaps.

In a 2022-23 test campaign, the JRC has assessed seven mature Alternative PNT technologies. All demonstrated enhanced cybersecurity, ability to provide position and excellent UTC transfer. One weakness is the inability of those systems to maintain their time scale to UTC without a direct connection to the National Metrological Institutes or local atomic clocks.

Given that ERNP describes the future Complementary PNT (C-PNT) as a mix of independent PNT systems underpinned by the GNSS, this system of systems approach allows for additional resilience and monitoring of the critical infrastructure while providing improved positioning for mass market users and enhancing other sectors.