US Patent 7152791 Identifying the location of an asset

According to an aspect of the present invention, an intelligent badge having the ability of collecting the identifiers of each of the badges located within the zone of the intelligent badge may be employed to identify the location of each badge. The central processing system determines the relative location of an asset by processing the sets of identifiers received from multiple intelligent badges. The relative location of an asset is determined by identifying at least one common badge identifier of a badge attached to a corresponding one of assets. The relative location of each asset may be determined with reference to known location of some badges by employing reference badges.