Alibaba Group Holding Limited
DISTANCE ESTIMATION USING SIGNALS OF DIFFERENT FREQUENCIES

Abstract:

A first signal generated from a signal generator may be synchronized with a local clock of a first device at a first time, and sent to a second device, the first signal having a first frequency. A second signal generated from the signal generator may be further synchronized with the local clock of the first device at a second time, the second signal having a second frequency different from the first frequency, and a difference between the second time and the first time being within a predetermined range of a predetermined time difference. The second signal may then be sent to the second device to enable the second device to determine a distance between the first device and the second device based at least in part on a phase difference between the first signal and the second signal.