Virtual Primary Reference Time Clock

The virtual Primary Reference Time Clock (vPRTC) is a highly secure and resilient network-based timing architecture that has been developed to meet the expanding needs of modern critical infrastructures. The vPRTC is simple in concept. It blends proven timing technologies into a centralized and protected source location and then uses commercial fiber optic network links and advanced IEEE^® 1588 Precision Time Protocol (PTP) boundary clocks to distribute 100 ns PRTC timing where it is needed in end points that might be hundreds of kilometers away. The central locations receive their UTC time traceability from GNSS via highly protected and validated receivers. Advanced firewall technologies continuously monitor for threats in the form of GNSS spoofing or jamming attacks to assure that only valid signals from the sky are passed to the central clock. The vPRTC uses industry-proven cesium atomic clocks to establish 30 ns guaranteed accuracy traceable to UTC. If an invalid GNSS signal is detected or denied, the vPRTC source maintains ±100 ns traceability to UTC for a minimum of 14 days. 

With these highly resilient clocks in place, critical infrastructure operators can use their secure fiber network to distribute protected timing to all necessary locations. Just as a GNSS-satellite-based timing system distributes timing to end points using open-air transmission, the vPRTC distributes timing using the fiber network. The difference is that the operator remains 100% in control of the network and can secure it as necessary. The vPRTC architecture can be deployed as the sole source of timing or it can be deployed as a backup to GNSS timing solutions.