QCNEWS
A Royal Navy trial with Saab and UK quantum clock startup Aquark used atoms chilled near absolute zero as a precise time reference to keep a ship's radar coherent after GPS timing was cut, the first GPS denied sea trial on the public record.
When the GPS signal that synchronizes a ship's radar network goes dark (jammed, spoofed, or simply unavailable), the network loses coherence. A Royal Navy trial with Saab and Aquark Technologies has now tested a backup: cold-atom atomic clocks that keep the network's timing stable without a satellite in the sky.
The mechanism is the same physics GPS itself relies on. GPS satellites carry atomic clocks that let receivers compute position to within meters by timing signals from at least four spacecraft. A warship's distributed radar network needs the same kind of shared time reference, at finer resolution, to keep its nodes coherent enough to track a single target together. The Royal Navy's trial, completed in 2026, swaps the satellite for a cold-atom clock, a sensor that traps and cools atoms to near absolute zero, then reads out their hyperfine transitions as a frequency standard, the way a cesium clock defines a second.
A ship's radar that loses GPS timing does not just lose position. The nodes drift relative to each other, and the picture on the operator's screen falls apart. Cold-atom clocks drift less per second than quartz oscillators, so the network can stay coherent for longer without re-disciplining to a satellite. That matters most in a fight, when the satellite is the first thing an adversary tries to deny. A warship under electronic attack does not get to pick which signal is jammed; it has to keep its sensors working anyway, on whatever clock is on board.
The Quantum Insider and Quantum Computing Report both frame the trial as the first time a cold-atom timing source has been used to hold a networked radar together at sea. The "world-first" wording, though, is the primary parties' (Saab, Aquark, and the Royal Navy), and no independent party has yet published a performance number, a stability figure, or a benchmark against a classical timing chain. The trial's most concrete operational result on the public record is the UK Defence Journal headline: the radar network kept working after GPS timing was cut. If the clocks had not held timing under the cut, that operational result would not be on the record.
Saab's role, per the company's UK press release and the PDF press cue cue-26-035, is the radar network and the integration onto a Royal Navy platform. Aquark's role, per its sea-trial blog post and its networked-radar post, is the cold-atom clock miniaturised to ship-fit size and power. The Royal Navy supplies the platform, the operational test plan, and the test range.
What is not yet on the record is the next step. Saab, Aquark, and the Royal Navy have not published a date for a second trial, a target system for procurement, or a comparison figure against the timing chain warships use today. The first independent readout, whether a published stability number, a peer-reviewed paper, or a procurement line in a UK or NATO budget, is what would turn the trial from a milestone into a capability.
The trial's operational result, a radar network holding together under a GPS cut, is now the bar any future cold-atom-at-sea readout has to clear. The next questions are whether the same physics can hold a drone swarm coherent, time-sync a communications network, or replace the satellite fixes a submarine needs to keep its position estimate from drifting underwater, and how soon any of that gets an independent number on the public record.