The development and advancement of atomic clocks have significantly transformed various fields, particularly navigation, telecommunication, and aviation. These highly precise timing devices fundamentally enhance the accuracy of Global Navigation Satellite Systems (GNSS), among other applications.
Atomic clocks operate by monitoring the resonant frequency of atoms. The most prevalent type, based on cesium, measures time using the oscillations of cesium-133 atoms, making them exceptionally precise, with accuracies approaching one second in 300 million years. Optical clocks, which use higher frequency light to measure time, are even more accurate, with future prospects of redefining the second potentially being based on these technologies4. Innovations in this area have yielded atomic clocks that are not only highly stable but also capable of achieving a fractional frequency uncertainty of 10^-18 or better.
The accuracy of atomic clocks underpins many essential technologies. For instance, GNSS—comprising systems like GPS, GLONASS, Galileo, and BeiDou—relies on precise timing to determine geographical locations based on satellite signals. Each satellite utilizes atomic clocks to provide timing signals, which are crucial for calculating distances and ensuring the accurate functioning of navigation systems15. A timing error of even a nanosecond can result in positional errors of approximately 30 centimeters.
In summary, the evolution of atomic clocks has not only redefined precision in timekeeping but has also facilitated remarkable advances in navigation, telecommunications, and aviation. With ongoing innovations in optical clock technology, the future holds exciting possibilities for enhancing precise time measurement and, consequently, the technologies that depend on it. As atomic clock performance continues to improve, it is expected that they will play a critical role in developing more advanced positioning systems critical for modern society’s functioning.