World’s first: Quantum optical clock tested on underwater autonomous sub

October 29, 2025, by Fatima Bahtić

In a world-first breakthrough for maritime technology, a quantum optical atomic clock has been successfully tested aboard an underwater autonomous submarine.

As informed, the test was performed by global quantum tech company Infleqtion, in partnership with the Royal Navy and MSubs.

The milestone trial saw Infleqtion’s Tiqker optical atomic clock integrated into the Royal Navy’s Excalibur (XCal) extra-large uncrewed autonomous vehicle (XLUAV), marking a significant advancement in positioning, navigation, and timing (PNT) for GPS-denied environments. The test demonstrated Tiqker’s ability to provide ‘ultra-precise timekeeping for long-duration underwater missions’.

Infleqtion is the first external technology partner invited to take part in the Royal Navy’s Excalibur program, which serves as a testbed for advancing the UK’s autonomous underwater capabilities. The vessel was named in May this year.

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UUV/UAV

“This experiment was a first critical step towards understanding how quantum clocks can be deployed on underwater platforms to enable precision navigation and timing in support of prolonged operations,” said Commander Matthew Steele, Head of Futures in the Royal Navy’s Disruptive Capabilities and Technologies Office (DCTO).

“We look forward to championing further trials of quantum-based navigation technologies onboard Excalibur as we seek to deliver quantum operational advantage for the Royal Navy.”

Unlike surface vessels, submarines cannot rely on Global Navigation Satellite Systems (GNSS) for accurate positioning and timing. Traditional microwave-based clocks are prone to drift over time, which can degrade navigation accuracy in GPS-denied environments.

By contrast, Infleqtion’s Tiqker optical atomic clock provides laboratory-grade precision in a compact, ruggedised form, maintaining an accurate “time heartbeat” even during extended submersion, it was noted.

The quantum timing system also enhances other key submarine functions, including sonar, secure communications, and fire control systems, improving performance across multiple domains.

The Excalibur trial confirmed Tiqker’s reliable operation through multiple dives, validating its robustness for real-world naval conditions. Further benchmarking against high-grade time standards is expected in upcoming phases.

The demonstration builds on the Royal Navy’s growing portfolio of quantum sensing technologies. In 2022, the navy installed quantum technology on its biggest warship, aircraft carrier HMS Prince of Wales, to help ensure pinpoint accuracy wherever the ship sails.