A position location system is described for determining position of mobile tags attached to assets or people. Zone tags are installed in the venue to assist in position location estimation of mobile Tags. One embodiment describes systems and methods for the zone tags to automatically determine their position location. Another embodiment describes systems and methods to detect that a zone tag has been moved and to determine the new position of the moved zone tags. Another embodiment describes systems and methods whereby mobile tags determine a list of zone tags with which to make range measurement for determining the mobile tag's position location.