A system for providing coordinate-based location information may include first, second and third wireless location transmitters. The wireless location transmitters may be located at fixed positions within an enclosure, such as a building. The wireless locations transmitters may each be programmed with...http://www.google.de/patents/US7603128?utm_source=gb-gplus-sharePatent US7603128 - System and method for wireless distribution of location-based information in an enclosure
