Patent ID: 8334801

Claim:
A locating system, comprising: at least one initiator configured to operate at a first clock frequency, and to transmit a measurement signal including a first preamble; and at least one transponder configured to operate at a second clock frequency; wherein the transponder includes: a first transceiver configured to receive the measurement signal and to perform synchronization with the first preamble; a first programmable device configured to detect a first plurality of skips during the performance of synchronization, and to count a first plurality of numbers of clock cycles for the first plurality of skips; and the first transceiver configured to transmit a response signal to the initiator, the response signal including a second preamble and a data payload including the first plurality of numbers of clock cycles; and wherein the initiator includes: a second transceiver configured to receive the response signal and to perform synchronization with the second preamble; a second programmable device configured to detect a second plurality of skips during the performance of synchronization, and to count a second plurality of numbers of clock cycles for the second plurality of skips; and a microcontroller configured to calculate a first time adjustment based on the first plurality of numbers of clock cycles, to calculate a second time adjustment based on the second plurality of numbers of clock cycles, and to calculate, based on a coarse time estimate, the first time adjustment, and the second time adjustment, a distance between the initiator and the transponder for determining a location of the transponder.