Nordic Semiconductor ASA
DETERMINING DISTANCE BETWEEN TWO RADIO TRANSCEIVERS

Abstract:

A method for determining a distance between an initiator radio transceiver and a reflector radio transceiver is provided. The method comprises the initiator radio transceiver transmitting a first radio signal at a first transmission time and the reflector radio transceiver receiving the first radio signal at a first reception time. The reflector transceiver samples the first radio signal using a sampling clock signal having a sampling period and determines a first reception-time value at a temporal resolution that is finer than the sampling period, including a fractional component representative of a fraction of the sampling period. The reflector transceiver transmits a second radio signal at a second transmission time that is offset from the sampling clock signal by an amount that depends on said fractional component so as to provide a predetermined dwell time that is determined to an accuracy finer than the sampling period. The initiator radio transceiver receives the second radio signal at a second reception time and determines a distance value representative of a distance between the initiator radio transceiver and the reflector radio transceiver.