Object tracking

Methods and systems for tracking objects. Systems of the present invention include a base station capable of transmitting and receiving signals at multiple frequencies. Each object to be tracked has attached to it what for the purpose of the present specification is referred to as an electronic tag (“E-Tag”). Each E-Tag can transmit signals that can be received and interpreted by the base station and each E-Tag can receive and interpret signals transmitted by the base station. The transmitting (and receiving) of signals between the base station and an E-Tag allows the base station to track the E-Tag, and therefore, track the object to which the E-Tag is attached. Methods utilized to track objects in accordance with the present invention vary depending on the distance of the object from a base station (“range” of the object). The distances from the base station are divided into zones with the lowest numbered zone (that is, zone 1) being closest to the base station and the highest numbered zone being farthest away from the base station. Typically, embodiments of the present invention are adapted to track objects in four different zones. LF and HF communications can be utilized to track objects in zones 1 and 2, triangulation can be used to track objects in zone 3, and global location techniques can be utilized to track objects in zone 4. In a typical application, zone 1 covers a storage enclosure such as a desk drawer, a file cabinet, or a safe for example. Zone 2 frequently covers a room or a building, zone 3 covers up to the maximum distance for which triangulation technology can be used to track an object, and zone 4 covers the maximum distance for which global location techniques can be used to track an object.