Spacecraft may one day navigate in space by using X-ray signals from rotating pulsars as a sort of cosmic GPS, German researchers say.

Pulsars are dense, collapsed stars that rotate rapidly, sending radiation sweeping around galaxies at repeating rates that rival atomic clocks in their timing, the scientists said.

Researchers at the Max Planck Institute for Extraterrestrial Physics said a spacecraft equipped to detect the pulses could compare their arrival times with those predicted at a reference location and determine its position to within 3 miles anywhere in the galaxy.

"The principle is so simple that it will definitely have applications," institute researcher Werner Becker told the BBC. "These pulsars are everywhere in the universe and their flashing is so predictable that it makes such an approach really straightforward."

The proposed technique is similar to the one used in the popular Global Positioning System, which broadcasts timing signals to the user from a constellation of satellites in orbit.

Becker presented his team's research at the U.K. National Astronomy Meeting in Manchester, England.