Ancient navigators once looked to the stars to find out where they were. Today, people are still looking to the skies for the same purpose, but they're getting the information from satellites, not the stars.

A group of Stanford University academics wants to make such navigation so accurate that it could tell whether you are in your car or standing next to it.

Since the government first launched a satellite navigation system known as the global positioning system in 1978, the system's ability to pinpoint the location of an object has steadily improved.

GPS receivers used to be bigger than a brick a decade ago and were accurate to within about 100 meters. Today a handheld $ 100 GPS receiver can fix a point on the ground within five or 10 meters, while more expensive military systems can zero in on the receiver within five meters or less.

But the GPS system doesn't get much better than that, and it doesn't work indoors or in deep urban canyons where a target object isn't within the line of sight of two or more satellite. And it isn't that hard to jam GPS signals.

Such a system isn't good enough for James Spilker and Per Enge, who are among the founders of the Stanford Center for Position, Navigation and Time. Spilker, a founder of navigation chip start-up Rosum and one of the creators of GPS, believes satellite navigation is just in its infancy.