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GPS technology, the backbone of navigation systems from smartphones to drones, relies on atomic clocks in satellites to provide accurate location data within a few meters. Now, a team of scientists is working to significantly improve this precision, potentially down to just a few centimeters, which would greatly benefit navigation systems.
The key to achieving this higher precision lies in replacing current atomic clocks with optical atomic clocks, which offer a remarkable improvement in timekeeping accuracy. While traditional atomic clocks are accurate to one second in millions of years, optical atomic clocks can achieve an error of just one second in billions of years. According to Minghao Qi, professor of electrical and computer engineering at Purdue University, this change in accuracy means that GPS systems would be accurate to the centimeter level.
However, optical atomic clocks, as they currently exist, are bulky, occupying several square meters in laboratory settings. This makes them impractical for use in satellites or portable devices like smartphones. To address this challenge, researchers at Purdue University and Chalmers University of Technology have developed a groundbreaking solution that could miniaturize these clocks without compromising their precision.
According to Interesting Engineering, the key innovation is the use of microcombs, tiny chip-based devices capable of generating a spectrum of evenly spaced light frequencies. These microcombs help convert the ultra-high-frequency oscillations of optical atomic clocks into lower, more manageable frequencies. By locking one of the microcomb’s frequencies to a laser, which is then synchronized with the clock’s oscillation, the system creates a stable reference for precise timekeeping.
Initially, one microcomb wasn’t sufficient to handle the atomic clock’s ultra-fast time signals. However, the researchers solved this by pairing two microcombs with a small frequency offset (around 20 GHz), enabling the system to measure time and position accurately.
While the microcomb chip represents a significant leap forward, additional components like optical amplifiers and modulators are still needed to complete the system. Future research will focus on integrating these components into a chip, potentially allowing the mass production of ultra-precise optical atomic clocks for widespread use in GPS satellites and consumer devices.
The study, published in Nature Photonics, highlights the exciting potential of this technology in transforming GPS and positioning systems worldwide.
