Cool nanotechnology:

The device, known as a quantum accelerometer, is actually based on a discovery made in 1997. Back then, scientists realized that when you trap a cloud of atoms in a vacuum with lasers, it can be cooled to just above absolute zero. Fast forward to 2014, and a group of researchers at the UK Defense Science and Technology Laboratory at Porton Down found the frosty atoms can be easily disturbed by an outside force. When you point another laser in the vacuum, you can track the atoms and determine their location based on the force of their movements. In the case of that submarine we mentioned, the "force" it's tracking is the sub rocking back and forth under the sea. The group will test a prototype of the device, which is about the size of shoebox, on land in a stripped-down form in September of 2015. If those trials are successful, we could eventually see the technology used in future vehicles, planes and even smartphones.