Patent ID: 6377203
Filing Date: 2002-04-23
Classification: G06K

Abstract:
A method for communicating with a plurality of buried transmitters, comprising the steps of:a) transmitting an interrogation signal requesting all buried transmitters receiving the interrogation signal to respond in a primary channel; b) assigning each buried transmitter whose reply signal is successfully received a unique dedicated channel in a first group of channels; c) assigning all buried transmitters whose reply signal is not successfully received to a first channel in a second group of channels; d) commanding all buried transmitters currently assigned to the first channel in the second group of channels to move to one of the channels in the second group of channels based on a portion of a number available to each of the buried transmitters; e) detecting an acknowledgment from each buried transmitter indicating which channels among the first and second groups of channels are occupied; f) commanding, one by one, those buried transmitters assigned to each of the channels in the second group of channels in step d) to transmit a signal in the primary channel; g) commanding those buried transmitters whose signals are successfully received in step f) to move to a unique dedicated channel in the first group of channels; and h) repeating steps c) through g) until all buried transmitters are assigned a unique dedicated channel in the first group of channels.