Patent ID: 8779901

Claim:
An asymmetric RTT ranging method for location determination between an interrogator device and a tag device, comprising: the interrogator device transmitting a first wireless signal and initiating a time measurement; the tag device receiving the first wireless signal and determining a composite arrival time of the first wireless signal and transmitting a second wireless signal after a predetermined period of time; the interrogator device receiving the second wireless signal and determining a first arrival time and a composite arrival time of the second wireless signal, concluding the time measurement; and compensating the time measurement at least in part by the difference in time between the first arrival time and the composite arrival time of the second wireless signal wherein the compensated time measurement is useful to determine ranging between the interrogator device and the tag device, wherein a bandwidth of the first wireless signal transmitted by the interrogator device and a bandwidth of the second wireless signal transmitted by the tag device differ by a factor of approximately four or more with the bandwidth of the second wireless signal approximately four or more times the bandwidth of the first wireless signal.