Patent ID: 6590537
Filing Date: 2003-07-08
Classification: G01S

Abstract:
A system comprised of a broadcasting master station, a multiplicity of fixed receivers, and a multiplicity of mobile transceiver units whereinthe master station initiates the process of locating specific mobile transceiver units with a periodic broadcast; the fixed receivers are used as reference points for multi-lateration of the mobile transceiver units; the mobile transceiver units respond to the master station; the master station broadcast and the mobile transceiver broadcasts are on separate frequencies; the master station broadcast activates a specific mobile transceiver unit to respond by embedding a unique mobile transceiver unit identifier in the master station broadcast; the mobile transceiver broadcasts are received by a multiplicity of fixed receiver stations; the fixed receiver stations report to the master station via a system network comprised of wireline, wireless, or a combination connectivity; each fixed receiver report includes the mobile unit identifier, the system time stamp of the master station broadcast the mobile transceiver unit responded to, and a system time stamp from the time the mobile transceiver broadcast was received by the fixed receiver; and the master station mathematically selects the set of four fixed receiver stations with the closest to uniform ninety degree separations in spherical coordinates in relation to an initial determination of the mobile unit from the available fixed receivers reporting a mobile transceiver unit response to determine the location of the mobile transceiver unit.