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Location detection system and method

  • US 9,658,312 B2
  • Filed: 08/26/2014
  • Issued: 05/23/2017
  • Est. Priority Date: 08/26/2013
  • Status: Active Grant
First Claim
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1. A method for detecting the location of a mobile device within an area, comprising the steps of:

  • storing a prior location estimate for the device;

    determining, for each of a plurality of zones in said area, a signal-based value indicative of the likelihood of the device being located in the respective zone, based on measured wireless signal characteristics;

    maintaining a set of transition values, each transition value representing a likelihood of a device moving between a pair of said zones;

    calculating, for each of a plurality of zones in said area, a current location value by using a matrix-based approach to combine (i) the prior location estimate, (ii) said set of transition values, and (iii) said signal-based values;

    wherein said set of transition values includes at least one transition value representing the likelihood of the device moving between a pair of zones which are physically accessible from one another and at least one transition value representing the likelihood of the device moving between a pair of zones which are physically inaccessible from one another; and

    wherein said step of calculating a current location value includes;

    using a discriminative model to calculate a current location value for at least one zone physically accessible from a zone corresponding to the prior location estimate, and a current location value for at least one zone physically inaccessible from said zone corresponding to the prior location estimate; and

    determining whether the device is in a boundary region adjacent to the meeting of two or more zones, wherein for each candidate location Li of n location candidates L1, L2, L3, . . . , Ln, a probability value P(Li) is assigned according to the likelihood of the device being in that candidate location, and wherein the determination that the device is in a boundary region between two locations Li, Lj is made where the following conditions are met;

    P(Li|s)>

    P(Lj|s)>

    P(Lk|s), for i, j, k=1, 2, 3, . . . , n, k≠

    j≠

    i, and P(Li|s)−

    P(Lj|s)<

    c, where c is a tuneable parameter and c<

    1, and s is the observed signal strength vector on the mobile device.

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