Patent ID: 6795491
Filing Date: 2004-09-21
Classification: G01S,H04B

Abstract:
A method for determining a distance between a first transceiver and a second transceiver, comprising the steps of:(a) determining an approximate separation distance between said first and second transceivers; (b) choosing a first transmission time for transmitting a first distancing communication from said first transceiver to said second transceiver; (c) choosing a first delay time for said second transceiver to wait from a first central time of a first reception window before transmitting a second distancing communication back to said first transceiver, said first central time of said first reception window being equal to said first transmission time plus said approximate separation distance divided by the speed of light; (d) transmitting said first distancing communication from said first transceiver to said second transceiver at said first transmission time; (e) receiving said first distancing communication at said second transceiver during said first reception window; (f) transmitting said second distancing communication from said second transceiver to said first transceiver after said first delay time; (g) determining a first arrival time of said first distancing communication at said second transceiver subsequent to step (f); (h) receiving said second distancing communication at said first transceiver during a second reception window, a second central time of said second reception window being equal to said second transmission time plus said approximate separation distance divided by the speed of light; (i) determining a second arrival time of said second distancing communication at said first transceiver; and (j) calculating a first updated separation distance between said first and second transceivers based on said first and second arrival times.