Accurate Time Reference in GPS-Denied Environments

Accurate Time Reference in GPS-Denied Environments

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While many navigation and timing devices are based on GPS, more and more technologies offer to back up the services provided by GPS should GPS signals be jammed, spoofed or unavailable.

Critical industrial, financial, military and governmental applications increasingly require accurate, reliable, and traceable signals for time and synchronization. Key fields of application include banking and finance, telecom networks and electricity grids. Accurate clocks across different nodes make possible key functions like consistency, event ordering, causality and the scheduling of tasks and resources with precise timing.

Time reference in GPS-denied environments is one of these cases. A new precision time technology called White Rabbit functions in both local and wide-area deployments. It provides a very stable time references over fiber in GPS-denied scenarios as a backup source or to complement other PNT solutions that require precise time and timing distribution.

Seven Solutions from Spain was one of 11 firms selected by the US Department of Transportation to demonstrate GPS backup technologies. The company provides time as a service, remote timing monitoring, GPS jamming protection and solutions for intra- and inter-datacenter synchronization, with up to sub-nanosecond precision.

One of the company’s time services works at the Madrid Stock Exchange, according to insidegnss.com. 

In finance and e-commerce, clock synchronization is crucial for determining transaction order: a trading platform needs to match bids and offers in the order in which they were placed, even if they entered the trading platform from different gateways. In distributed databases, accurate clock synchronization allows a database to enforce external consistency and improves the throughput and latency of the database.

White Rabbit is a collaborative project for the development of a new Ethernet-based technology to ensure sub-nanosecond synchronization and deterministic data transfer. The project uses an open-source paradigm for the development of its hardware, gateware and software components.