An interplanetary GPS using pulsar signals

May 24, 2013

Artist’s impression of a rotation-powered pulsar. The neutron star appears as a pulsating source of radiation if the rotating emission beam crosses the observer’s line of sight. Averaging these periodic pulses of intensity over many rotation cycles results in a stable pulse profile. Because of the timing stability of most pulsars, the arrival time of pulses can be predicted with very high precision, which is an essential requirement for a navigation system based on pulsar observations. (Credit: Werner Becker, Mike G. Bernhardt, Axel Jessner)

Researchers have worked out the practical details for an autonomous spacecraft navigation system using signals from pulsars in essentially the same way that we use GPS satellites to navigate on Earth, MIT Technology Review reports.

A pulsar is a rotating neutron star that emits a beam of electromagnetic radiation at a very precise interval between pulses that ranges from milliseconds to seconds.

By measuring the arrival time of pulses from at least three different pulsars and comparing this with their predicted arrival time, it is possible to work out a position in three-dimensional space.

The researchers at the Max Planck Institute for Radio Astronomy in Germany say that technology being developed now would allow spacecraft to work out their position to within five kilometers anywhere in the solar system.

The researchers calculate that for 21-centimeter waves, the spacecraft would require an antenna with a collecting area of 150 square meters.

But a better idea, they say, is to use pulsars that emit x-rays, since the technology for collecting and focusing x-rays has improved dramatically in recent years.