Jimme Blue writes: The use of pulsars as a GPS analogue holds the promise of fixing a spacecraft's location to within 5 km, anywhere in the galaxy. While not ready for immediate use, it may be ready for use within the Solar System in the next 10-15 years. Link to Original Source
The most difficult thing in the world is to know how to do a thing and to
watch someone else doing it wrong, without commenting.
-- T.H. White