Translate relative coords to global

I’m working in AS3, and I have a class that is not created at run time, but is dragged into a specific position onto the stage before publishing. This class then spawns some other MovieClips every few frames, and adds them to the stage. But I need some way of determining the spawners global position, so that the MovieClips it creates are put in the correct location. It has no knowledge of any parent movie clips that it (may) be in.