US Patent 11131765 Positioning device, communications system and method

A device can determine its position in a communications system. A scalable solution permits multiple devices to be used in one area without detrimental effect on the accuracy or latency of the position determining. The communications system includes a first base station arranged to transmit a first signal to a second base station arranged receive the first signal and transmit a second signal to the first base station in response The first base station is arranged to receive the second signal and transmit a third signal to the second base station in response to the second signal delay time measuring unit, round trip time measuring unit, a base station timings unit and a calculating unit are used to calculate a first time difference of arrival based on a first round trip time, first delay time, second round trip time and a second delay time.