Efficient Datacenter Multi-zone GNSS Timing & Distribution, or How to Stop Your Roof Looking Like a Mushroom Farm

Richard Jacklin

Abstract:	Datacenters typically guarantee their customers operational excellence, 5 nine’s uptime and 24/7 support. Many of the datacenter customers require timestamp capability, particularly those customers that are financial traders and who now have additional regulatory requirements in this area. Timestamping is essential for post-trade transparency and detecting instances of market abuse. Automated and algorithmic trading can create thousands of trades per second and these trades need to be timestamped against a common time standard. For high frequency trading, a typical standard for maximum divergence from Co-ordinated Universal Time (UTC) must be less than 100 microseconds, with a 1 microsecond granularity; not something your typical PC clock can deliver! A common way of deriving accurate timestamps is through the GNSS system; this is locked to UTC. Assuming the datacenter has many customers or zones for which GNSS needs to be supplied, how do we stop the roof looking like field of mushrooms? An additional challenge is that GNSS signals are very small (even with active amplification in the antenna) and routing small - high frequency signals (~1.5GHz / L1 / L2 band) for 100’s feet / meters through coax is a problem. Coax is lossy at this frequency, has high footprint for many cables, and has a limited shielding effectiveness. So we need another solution, this presentation goes on to present a practical answer; GNSS distribution through an RF over Fiber transport solution. Useful for datacenter managers or anyone in IT / telecoms that needs distributed GNSS timing solutions.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	2087 - 2103
Cite this article:	Jacklin, Richard, "Efficient Datacenter Multi-zone GNSS Timing & Distribution, or How to Stop Your Roof Looking Like a Mushroom Farm," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 2087-2103. https://doi.org/10.33012/2018.16022
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