One of the marvels of the modern world that we tend to take for granted is GPS. Thanks to the Global Positioning System and its network of precisely positioned satellites, anyone on the Earth’s surface can locate themselves to within a few feet. That’s a convenience that navigators even a hundred years ago would have killed for.
Still, GPS is not perfect. Sometimes we lose GPS signal when traveling through tunnels, and sometimes the signal is not nearly as accurate as it should be. Even for a modern marvel, GPS can still be a headache to deal with. A new invention, though, might be able to fix that by shrinking down the atomic clocks used on the GPS satellites to a portable size.
GPS works because of a series of incredibly accurate clocks built in to each member of the satellite constellation. These atomic clocks are so accurate they lose less than one second every ten billion years. That level of precision is essential because GPS systems have to take time effects from Einstein’s Theory of Relativity into account when calculating your position. If the onboard clock is even a fraction of a second off, it could miscalculate your position by dozens or hundreds of feet.
When the GPS device in your car or phone loses connection with the GPS satellites overhead, it also loses connection with those hyper-accurate clocks. The result is that we become untethered and lost. To fix this problem, a group of scientists at the University of Sussex in England have developed a way to shrink atomic clocks down to the point where they can truly become portable.
The breakthrough rests on the central way that atomic clocks operate. Atomic clocks keep time by referring to the frequency of light emitted by a specific atom. The actual device that measures that frequency is called the ‘comb,’ and it’s typically one of the largest components in a modern atomic clock. The Sussex researchers have developed a way to dramatically reduce the size of the comb by integrating it with a tiny chip.
The result is a tiny timekeeping chip that uses substantially less power than a standard atomic clock. There’s still a long way to go before small atomic clocks start making their way into daily life, but this is an important milestone that shows these clocks are on the way.
Source: University of Sussex
Originally posted on Popular Mechanics