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Method and system for locating sensor node in sensor network using distance determining algorithm

  • US 7,855,684 B2
  • Filed: 11/14/2008
  • Issued: 12/21/2010
  • Est. Priority Date: 11/15/2007
  • Status: Expired due to Fees
First Claim
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1. A position locating system for a sensor network, comprising:

  • a plurality of reference nodes, each reference node of said plurality of reference nodes having self-positional information regarding a respective position thereof; and

    a sensor node having a position location table,wherein each reference node comprises;

    a control unit for generating, in response to a location information request signal, a location information; and

    a radio frequency (RF) communication unit for receiving a location information request signal and for forwarding the received location information request signal to the control unit, controlling transmission power, and sending the generated location information in return,wherein the sensor node comprises;

    a control unit for generating a coordinate request signal, analyzing transmit power levels extracted from location information from reference nodes, and for calculating coordinates of a position of the sensor node using the position location table; and

    an RF communication unit for transmitting the coordinate request signal, and for receiving location information and forwarding the location information to the control unit,wherein the position location table is formed by providing a grid of a preset number of vertical and horizontal lines corresponding to a square area defined by an arrangement of the plurality of reference nodes;

    wherein measured distances from each intersection point in the grid to each of the reference nodes, respectively correspond to transmit power levels;

    wherein intersection points sorted according to transmit power level patterns are arranged into sorted groups in which each particular group has a middle point of those intersection points belonging to the particular group; and

    error calculating means for calculating errors for all groups to determine whether a largest group error is within a desired error boundary.

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