Patent ID: 6552661
Filing Date: 2003-04-22
Classification: G06K

Abstract:
A locator comprising:a. a receiver that provides a plurality of signals each signal having respective indicia of identification device presence within a respective communication pattern; and b. a processor that performs a method for determining whether a first identification device is located within a zone, the method comprising: determining, in response to signals of the plurality, a respective reliability of communication between the receiver and a plurality of identification devices, the plurality comprising the first identification device and at least one second identification device, wherein: (1) a first and a second communication pattern each respectively has a periphery such that communication with a provided identification device when located beyond the periphery is less reliable than communication with the provided identification device when located within the periphery; (2) the first identification device is located within the periphery of the first pattern; (3) each second identification device is located beyond the periphery of the first pattern and within the periphery of the second pattern; and (4) the first pattern has a periphery substantially within the zone; comparing each respective reliability of communication to a respective threshold to identify validly present identification devices; determining that the first identification device is within the zone in accordance with whether the first identification device is validly present within the first pattern, the second identification device is validly present within the second pattern, and the second identification device is not validly present within the first pattern.