Patent ID: 8214147

Claim:
A navigation unit comprising: a transceiver for transmitting and receiving ultra wideband signals, a central processing unit for performing operations, a power source for powering the transceiver and the central processing unit, and software stored on and executed by the central processing unit for diagnosing and managing the navigation unit, and for calculating position of the navigation unit using range measurements to and between a plurality of base stations, wherein the plurality of base stations is initialized to determine their relative locations to each other in a coordinate system wherein, during initializing, a first base station of the plurality of base stations sends an ultra wideband signal to a second base station and a third base station of the plurality of base stations to determine a distance between the first base station and the second base station and a distance between the first base station and the third base station and wherein the second base station sends an ultra wideband signal to the third base station to determine a distance between the second base station and the third base station; determining the range measurements, at the navigation unit, by measuring the time of arrival of at least one ultra wideband signal from each of the plurality of base stations; calculating directly the location of the navigation unit relative to the plurality of base stations, where the plurality of base stations is at least three when a time of arrival technique is used and wherein the plurality of base stations is at least four when a time difference of arrival technique is used.