InterPlanetary Network

The InterPlanetary Network (IPN) is a group of spacecraft equipped with gamma ray burst (GRB) detectors. By timing the arrival of a burst at several spacecraft, its precise location can be found. The precision for determining the direction of a GRB in the sky is improved by increasing the spacing of the detectors, and also by more accurate timing of the reception. Typical spacecraft baselines of about one AU (astronomical unit) and time resolutions of tens of milliseconds can determine a burst location within several arcminutes, allowing follow-up observations with other telescopes.