Method for estimating relative clock frequency offsets to improve radio ranging errors

摘要

A method and system improves two-way radio ranging accuracy by estimating a relative clock frequency offset between a first clock X of a first transceiver and a second clock Y a second transceiver. The first transceiver transmits a first packet at time t0 received by the second transceiver at a time t1. The second transceiver transmits a second packet at a time t2 received by first transceiver at a time t3. The second transceiver transmits a third packet at a time t4 received at a time t5. The relative clock frequency offset is then &Dgr; ⁢ ⁢ f XY ′ ≅ 2 ⁢ ⁢ f ⁡ ( N 24 Y - N 35 X ) N 24 Y + N 35 X , where f is a nominal clock frequency of the first and second clocks, NY24 is a measured first delay between times t2 and t4 of the second clock, NX35 is a measured second delay between times t3 and t5 of the first clock X.