TL;DR
- ▸CISA has recognised that GNSS-derived timing is increasingly load-bearing for US critical infrastructure and that the resilience hasn't kept pace.
- ▸The recommendations cover GNSS hardening, PNT diversification, monitoring of timing-related anomalies and incident reporting.
- ▸Operators should treat timing infrastructure as critical infrastructure — the guidance is directional, but the expectations are firming up.
What CISA recommends
The US Cybersecurity and Infrastructure Security Agency has published guidance recognising that GNSS-derived timing is increasingly load-bearing for US critical infrastructure and that the resilience of timing infrastructure has not kept pace with its growing importance. The recommendations cover four areas. GNSS hardening: multi-band, multi-constellation receivers with anti-jam capability where the threat model justifies it. PNT diversification: avoiding sole reliance on a single GNSS source by incorporating alternative time references where possible. Monitoring of timing-related anomalies: continuous observability of clock health with alerting on excursions. Incident reporting: documented procedures for detecting and reporting timing-related events.
The CISA guidance is consistent with the UK PNT framework, with DORA in the EU, and with similar movements internationally. The convergence is not coincidental — multiple national governments have independently reached the same conclusion that timing infrastructure is critical infrastructure and needs to be treated accordingly.
What operators should do
Treat timing infrastructure as critical infrastructure. Specify multi-band, multi-constellation GNSS with anti-jam where the threat model justifies it. Plan for credible GNSS denial scenarios with appropriate holdover and PNT diversification. Monitor the timing fabric continuously with central correlation across multiple devices. Document the incident response procedure for timing-related events. None of this is news to mature operators; CISA's contribution is to make the expectations explicit and the guidance public, which raises the bar for less mature operators and gives mature operators a published reference to point at when justifying resilience investment.
What's next
Expect the CISA recommendations to firm up into more explicit expectations over the next several years, particularly as specific critical infrastructure sectors are covered by sector-specific cybersecurity rules. Operators that build resilience into their timing architecture now will be ahead of the curve.
Where TimeBeat fits
TimeBeat builds the open-standard hardware grandmasters, anti-jam GNSS integration, Clock Ensemble multi-source aggregation and Sync Insight observability platform that US CNI operators use to meet CISA's expectations. Our customers across US critical infrastructure sectors include operators in finance, broadcast, telecom and defence who have identified resilience gaps and are addressing them ahead of formal regulation.
Frequently asked questions
What does CISA recommend for timing infrastructure?+
Are CISA recommendations legally binding?+
How do CISA recommendations compare to DORA and the UK PNT framework?+
Related reading
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