Use of RF signatures to detect moved wireless transmitters

An apparatus for identifying, using a mobile device, that a wireless transmitter has been moved, the apparatus comprising a memory and a processor, the apparatus further comprising:

• means for measuring signals, at the mobile device, from a plurality of wireless transmitters proximate to the mobile device;
• means for identifying, at the mobile device, a candidate wireless transmitter from the plurality of wireless transmitters, wherein the means for identifying the candidate wireless transmitter comprises means for determining whether a wireless transmitter of the plurality of wireless transmitters is a mobile wireless access point by determining whether the wireless transmitter has moved more than a predetermined number of times over a predetermined period of time and means for identifying the wireless transmitter as the candidate wireless transmitter responsive to the wireless transmitter not being a mobile wireless access point;
• means for obtaining, at the mobile device, a reference radio frequency (RF) signature associated with the candidate wireless transmitter, the reference RF signature comprising location-independent information associated with the candidate wireless transmitter;
• means for deriving, at the mobile device, an observed radio frequency (RF) signature for the candidate wireless transmitter from the measured signals of at least one wireless transmitter of the plurality of wireless transmitters other than the candidate wireless transmitter;
• means for determining, at the mobile device, whether the candidate wireless transmitter has been moved to a new location by comparing the observed RF signature for the candidate wireless transmitter to the reference RF signature associated with the candidate wireless transmitter;
• and
• means for generating, at the mobile device, an indicator indicative of whether the candidate wireless transmitter has been moved.

A mobile device for identifying that a wireless transmitter has been moved, the mobile device comprising:

• a tangible, non-transitory computer-readable memory;
• a plurality of modules comprising processor executable code stored in the memory;
• a processor connected to the memory and configured to access the plurality of modules stored in the memory;
• and
• a radio frequency (RF) signature module configured to
• measure signals from a plurality of wireless transmitters proximate to the mobile device;
• identify a candidate wireless transmitter from the plurality of wireless transmitters, wherein the RF signature module is configured to determine whether a wireless transmitter of the plurality of wireless transmitters is a mobile wireless access point by determining whether the wireless transmitter has moved more than a predetermined number of times over a predetermined period of time, and identify the wireless transmitter as the candidate wireless transmitter responsive to the wireless transmitter not being a mobile wireless access point;
• obtain a reference radio frequency (RF) signature associated with the candidate wireless transmitter, the reference RF signature comprising location-independent information associated with the candidate wireless transmitter;
• derive an observed radio frequency (RF) signature for the candidate wireless transmitter from the measured signals of at least one wireless transmitter of the plurality of wireless transmitters other than the candidate wireless transmitter;
• determine whether the candidate wireless transmitter has been moved to a new location by comparing the observed RF signature for the candidate wireless transmitter to the reference RF signature associated with the candidate wireless transmitter;
• and
• generate an indicator indicative of whether the candidate wireless transmitter.

A non-transitory computer-readable medium, having stored thereon computer-readable instructions for identifying, using a mobile device, that a wireless transmitter has been moved, comprising instructions configured to cause at least one processor to:

• measure, at the mobile device, signals from a plurality of wireless transmitters proximate to the mobile device;
• identify, at the mobile device, a candidate wireless transmitter from the plurality of wireless transmitters, wherein the instructions configured to cause the computer to identify the candidate wireless transmitter comprise instructions configured to cause the computer to determine whether a wireless transmitter of the plurality of wireless transmitters is a mobile wireless access point by determining whether the wireless transmitter has moved more than a predetermined number of times over a predetermined period of time, and to identify the wireless transmitter as the candidate wireless transmitter responsive to the wireless transmitter not being a mobile wireless access point;
• obtain, at the mobile device, a reference radio frequency (RF) signature associated with the candidate wireless transmitter, the reference RF signature comprising location-independent information associated with the candidate wireless transmitter;
• derive, at the mobile device, an observed radio frequency (RF) signature for the candidate wireless transmitter from the measured signals of at least one wireless transmitter of the plurality of wireless transmitters other than the candidate wireless transmitter;
• determine, at the mobile device, whether the candidate wireless transmitter has been moved to a new location by comparing the observed RF signature for the candidate wireless transmitter to the reference RF signature associated with the candidate wireless transmitter;
• and
• generate, at the mobile device, an indicator indicative of whether the candidate wireless transmitter has been moved.