Patent ID: 6965344
Filing Date: 2005-11-15
Classification: G08B

Abstract:
1. A wireless system for determining the location of a moveable object positioned in a structure, said structure having structural features, with each structural feature characterized by a determinable feature size, said system comprising: a signal emitter coupled to said object, said emitter for broadcasting a signal having a wavelength, λ; a means on said emitter for selectively setting the emitter signal wavelength, λ, with the selected wavelength, λ, being longer than said feature size wherein a signal path distortion of said signal is caused by said structure and is characterized by said signal wavelength, λ; at least three mutually dispersed base station sites for receiving said signal from said signal emitter at each base station site; at least one phase sensing circuit for determining phase information for each received signal, said phase information being dependent on said signal path distortion; and a central processing site connected in communication with each said base station site, said central processing site having a processor for using said phase information to determine the location of said signal emitter relative to each said base station site.