A system for determining the position of a labelled object within an environment containing a plurality of detectors sensitive to energy of a first type and located at known positions therearound, wherein the object has a transmitter for transmitting energy of the first type, and each object is labelled...http://www.google.de/patents/US6348856?utm_source=gb-gplus-sharePatent US6348856 - Detection system for determining positional and other information about objects
