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Energy efficient location tracking on smart phones

  • US 8,588,810 B2
  • Filed: 11/30/2011
  • Issued: 11/19/2013
  • Est. Priority Date: 11/30/2011
  • Status: Expired due to Fees
First Claim
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1. A method comprising:

  • operating a GPS-enabled cellular electronic device in an indoor mode;

    detecting, at said GPS-enabled cellular electronic device, an increase in strength of a cellular signal;

    responsive at least to said increase in cellular signal strength, transitioning said GPS-enabled cellular electronic device to an outdoor testing mode;

    detecting whether movement of said GPS-enabled cellular electronic device occurs during said outdoor testing mode;

    transitioning said GPS-enabled cellular electronic device to an outdoor mode, if said movement occurs;

    returning said GPS-enabled cellular electronic device to said indoor mode if said movement does not occur;

    detecting, at said GPS-enabled cellular electronic device, a decrease in strength of a Wi-Fi signal, wherein said transitioning of said GPS-enabled cellular electronic device to said outdoor testing mode is further responsive to said decrease in said Wi-Fi signal strength;

    detecting, at said GPS-enabled cellular electronic device, a loss of a GPS signal while said GPS-enabled cellular electronic device is in said outdoor mode; and

    responsive to said loss of said GPS signal, transitioning said GPS-enabled cellular electronic device back to said indoor mode;

    wherein;

    said detecting, at said GPS-enabled cellular electronic device, of said increase in strength of said cellular signal comprises determining that a sample of said strength of said cellular signal has increased relative to a preceding sample thereof and that an absolute value of a difference of said sample of said strength of said cellular signal from a mean value of said strength of said cellular signal exceeds twice a standard deviation of said strength of said cellular signal;

    said detecting, at said GPS-enabled cellular electronic device, of said decrease in strength of said Wi-Fi signal comprises determining that a sample of said strength of said Wi-Fi signal has decreased relative to a preceding sample thereof and that an absolute value of a difference of said sample of said strength of said Wi-Fi signal from a mean value of said strength of said Wi-Fi signal exceeds twice a standard deviation of said strength of said Wi-Fi signal;

    said detecting, at said GPS-enabled cellular electronic device, of said loss of said GPS signal comprises determining that a predetermined number of attempts to acquire said GPS signal have failed; and

    said detecting whether said movement of said GPS-enabled cellular electronic device occurs comprises determining whether an average, for a plurality of samples, of a sum of an absolute value of a change in acceleration in each of three orthogonal coordinate directions, exceeds a predetermined threshold.

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