Patent ID: 8421615

Claim:
A position locating system for a sensor network, comprising: a plurality of reference nodes, each reference node including location information of its own location; and a sensor node for computing a location thereof on a basis of respective location information of each reference node of said plurality of reference nodes, wherein each reference node of said plurality of reference nodes comprises: a control section for generating a location information signal including a transmit power level and said location information of its own location upon reception of a location information request signal; and a radio frequency (RF) section for forwarding the received location information request signal to the control section, and for controlling transmission power according to the transmit power level of the control section to send the generated location information signal, wherein said sensor node comprises: a control unit for computing a location of the sensor node and an associated error of the computed location on the basis of one or more location information signals received from neighbor reference nodes; an RF unit for sending said location information request signal to one or more of said plurality of reference nodes, and for receiving location information signals and forwarding the same to the control unit; and a storage unit storing the location information signals received from multiple neighbor reference nodes; wherein each reference node transmits location signals at a plurality of power levels, with each power level corresponding to a known transmission range; and the control unit of the sensor node computes a position and associated error range using only a location information signal from each reference node having a lowest transmit power level among the plurality of power levels that permits position and error range computation for that reference node.