The Global Position System has revolutionised navigation on Earth. It consists of a network of satellites that each broadcast a time signal. A receiver on Earth can then work out its position in three-dimensional space by comparing the arrival times of the signals from at least three satellites. But the system cannot help with navigation on an interplanetary scale or beyond.

Today, Bertolomé Coll at the Observatoire de Paris in France and a friend, Albert Tarantola, propose an interstellar GPS system that has the ability to determine the position of any point in the galaxy to within a metre.
Technology Review: Blogs: arXiv blog: How to Use Pulsars for Interstellar Navigation