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.
— Technology Review: Blogs: arXiv blog: How to Use Pulsars for Interstellar Navigation
this is some serious science, but it’s only going to be needed if we discover some method of faster then light travel, right? Using standard methods of space travel, we’d pretty much know where we are, due to the fact that we’re going so damn slow.