Two-Way Ranging Clock Offset Correction

The patent applies preliminary action by pre-measuring the duration of known signal frames (request frame duration T1 and reply frame duration T2) before performing the actual ranging calculation. These pre-measured durations are then used to compute a correction factor that compensates for clock frequency offsets. This approach allows the system to achieve high ranging precision without requiring complex real-time correction mechanisms, as the correction data is prepared in advance during the signaling phase.

The patent implements feedback by using the measured frame durations T1 and T2 to compute a correction factor that is then applied to the raw time of flight measurement. The correction factor is derived from the ratio of expected to actual frame durations, creating a feedback loop that compensates for clock frequency deviations. This feedback mechanism enables accurate ranging measurements while maintaining relatively simple implementation, as the correction is automatically computed from the signaling exchange itself.

The patent merges multiple measurement functions into a unified ranging process. Instead of performing separate measurements for clock calibration and distance calculation, the method combines these functions by measuring the durations of request and reply frames during the normal signaling exchange. These same measurements serve dual purposes: characterizing the clock frequency offset and enabling the distance calculation. This merging approach maintains high measurement precision while preserving ranging efficiency, as no additional measurement steps are required beyond the standard two-way ranging signaling.