Timing X-ray Pulsars with Application to Spacecraft Navigation

Usually, positions of spacecraft on interplanetary or deep space missions are determined by radar tracking from ground stations, a method by which uncertainty increases with distance from Earth. As an alternative, a spacecraft equipped with e.g. an X-ray telescope could determine its position autonomoulsy via onboard analysis of X-ray pulsar signals. In order to find out which pulsars are best suited for this approach and what accuracy can be achieved, we built up a database containing the temporal emission characteristics of the 60 X-ray pulsars for which a pulsed radiation has been detected by mid 2010.