Means for identifying a direct path signal in the presence of multi-path signals

摘要

A technique is disclosed for determining the timing of a received signal that includes one or more time delayed versions of a reference signal travelling over respective different signal paths. The technique includes correlating the received signal with the reference signal to produce a correlated signal; determining whether the correlated signal includes a signal peak that corresponds to the direct path of the received signal; and iteratively repeating these operations until a signal peak is determined to correspond to the direct path of the received signal. In each successive iteration, the reference signal is regenerated, and contributions from each regenerated reference signal are removed from the received signal prior to correlating the received signal in the next iteration. The technique is particularly suited for accurate determination of signal timing in a position determining system.