Indoor Location Positioning
Indoor GPS antennas won't help because they are just repeaters for the GPS antenna on the roof.  There will be propagation differences between the roof antenna and the repeaters, but these won't help resolve actual location differences.  The purpose of such antennas is to allow devices in the building to locate to that building and to provide the GPS time signal.

Indoor location is tricky business.  No single solution has emerged, although there are a number of companies trying to serve that space.  Some use WiFi signal strength, signal strength from active RF tags, carrier phase from active RF tags, ultrasound, IR, combinations of these, and probably more I am not aware of.