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See-Through Walls: Motion Tracking Using Variance-Based Radio Tomography Networks
May 2011 (vol. 10 no. 5)
pp. 612-621
Joey Wilson, University of Utah, Salt Lake City
Neal Patwari, University of Utah, Salt Lake City
This paper presents a new method for imaging, localizing, and tracking motion behind walls in real time. The method takes advantage of the motion-induced variance of received signal strength measurements made in a wireless peer-to-peer network. Using a multipath channel model, we show that the signal strength on a wireless link is largely dependent on the power contained in multipath components that travel through space containing moving objects. A statistical model relating variance to spatial locations of movement is presented and used as a framework for the estimation of a motion image. From the motion image, the Kalman filter is applied to recursively track the coordinates of a moving target. Experimental results for a 34-node through-wall imaging and tracking system over a 780 square foot area are presented.

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Index Terms:
Wireless networks, sensors, tracking, through-wall surveillance.
Joey Wilson, Neal Patwari, "See-Through Walls: Motion Tracking Using Variance-Based Radio Tomography Networks," IEEE Transactions on Mobile Computing, vol. 10, no. 5, pp. 612-621, May 2011, doi:10.1109/TMC.2010.175
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