France started developing quantum gravimeters (GIRAFE) in 2006 or so, with airborne versions trialed and ship and submarine trials due in 2023, for operational

France started developing quantum gravimeters (GIRAFE) in 2006 or so, with airborne versions trialed and ship and submarine trials due in 2023, for operational deployment in 2026–27. https://www.capital.fr/?authId=d61dc7363d8137e2e9555b95781855c4&redirectUri=%2Feconomie-politique%2Fla-marine-francaise-pourrait-etre-la-premiere-au-monde-a-utiliser-cette-technologie-revolutionnaire-1429014 https://www.capital.fr/?authId=d61dc7363d8137e2e9555b9578185... It's not just for dead-reckoning, they are also mapping the Earth's gravitational field for submarine navigation: https://www.onera.fr/en/news/shom-onera-cold-atoms-gravimetry https://www.onera.fr/en/news/shom-onera-cold-atoms-gravimetr...