Localization using access point

A system, comprising:

• a distance calculator to:
• use a first time of flight to determine a first distance between an access point and a mobile device at a first location;
• use a second time of flight to determine a second distance between the access point and the mobile device at a second location;
• and
• obtain a third distance between the first location and the second location;
• and
• a localizer to use the first, second, and third distances to localize the second location;
• and
• a time of flight calculator to:
• obtain a channel impulse response for a channel between the access point and the mobile device;
• use the channel impulse response to determine if a time of arrival of a packet from the mobile device to the access point corresponds to a reflected path between the mobile device and the access point;
• and
• if the time of arrival corresponds to a reflected path, use the channel impulse response to obtain a time of arrival correction;
• and
• use the time of arrival and time of arrival correction to calculate the first time of flight or the second time of flight.

A non-transitory computer readable medium storing instructions executable by a processor to:

• obtain a heading of a mobile device;
• obtain a channel impulse response corresponding to an access point;
• use the channel impulse response to estimate a positive bias due to multipath;
• use the positive bias to calculate a time of flight;
• use the time of flight to determine a first distance from the mobile device to the access point when the mobile device is at a first location;
• obtain a second distance from the mobile device to the access point when the mobile device is at the second location;
• track a step frequency of a user of the mobile device as the user travels from the first location to the second location;
• use a relationship between step frequency and step length to determine a third distance between the first location and the second location;
• and
• use the first distance, the second distance, the third distance, and the heading to localize the second location.