POSITIONING METHOD AND SYSTEM FOR COMPENSATION OF INTERNAL PROPAGATION DELAYS

In a method of determining position information of a client device (14), the client device and a plurality of reference devices (13-13''') communicate with one another over a wireless communication network. The plurality of reference devices comprise a master device (13) and target devices (13'-13'''). Clocks of the target devices are synchronized with a clock of the master device based on one-way message information. For each of the target devices (13'-13''') a first time correction representative of a sum of a transmit antenna delay of the respective target device, a transmit antenna delay of the master device, a receive antenna delay of the respective target device and a receive antenna delay of the master device is determined based on a two-way ranging message between the master device and the respective target device. A first message (31) transmitted from, or received by the respective target device is timestamped by each of a plurality of the target devices with a first timestamp corrected for the first time correction. The position information of the client device (14) is determined based on time- of-flight information of the first messages (31) in which the first timestamp is corrected for the first time correction. As a result, the timestamps of the first messages applied by the plurality of target devices will experience a same offset error. Consequently, the corresponding pseudo-ranges will all have the same error. Typically, positioning algorithms are insensitive to constant errors in the pseudo-ranges or can easily deal with them.