Patent ID: 6380894
Filing Date: 2002-04-30
Classification: G01S,G06K

Abstract:
A method of controlling the operation of a system for geolocating objects within a monitored environment, wherein transmissions from tags associated with said objects are detected at a plurality of spaced apart monitoring locations containing tag transmission readers, each respective monitoring location containing a plurality of transmission readers respectively employing mutually diverse antennas to minimize multipath interference at said antennas simultaneously, and outputs of said tag transmission readers are coupled over signal transport paths, having associated signal transport delays, to an object location processor which processes said outputs of said tag transmissions to geolocate said tags and thereby their associated objects within said monitored environment, said method comprising the steps of:(a) providing within said monitored environment at least one â€˜referenceâ€™ tag whose geolocation is known, and which is operative to transmit a reference tag signal encoded with information representative of the identification of said reference tag; (b) receiving said reference tag signal at said transmission readers, and coupling outputs thereof over said signal transport paths to said object location processor for processing thereby to determine the geolocation of said reference tag; (c) comparing the geolocation of said reference tag as determined in step (b) with the known geolocation of said reference tag; and (d) controllably adjusting the processing operation carried out by said object location processor to compensate for errors, such as those associated with delays through said signal transport paths, in accordance with a difference between the geolocation of said reference tag as determined in step (b) and the known geolocation of said reference tag.