Chronos - Decimeter-Level Localization with a Single WiFi Access Point:
The key enabler underlying Chronos is a novel algorithm that can compute sub-nanosecond time-of-flight using commodity WiFi cards. By multiplying the time-of-flight with the speed of light, a MIMO access point computes the distance between each of its antennas and the client, hence localizing it.
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Yet, emulating a wideband radio using packets transmitted on different frequency bands is not easy. Stitching measurements across such packets requires Chronos to overcome three challenges:
Resolving Phase Offsets: [...]
Eliminating Packet Detection Delay: [...]
Combating Multipath: [...]
The body of this paper explains how Chronos overcomes these challenges, computes the absolute time-of-flight, and enables localization using a single access point.