Patent ID: 9678195
Date: 2017-06-13
CPC Classifications: G01S,H04W

Claim:
1. Method of processing positioning signals in a positioning system employing a series of signal transmitters arranged at predetermined locations to emit respective energy pulses and an electronic device detecting arrival times of said pulses for use in determining a position of the electronic device, the method comprising: (a) obtaining a sampled signal by sampling an incoming signal at the electronic device over a time period; (b) determining a correlated signal by correlating the sampled signal with a comparison signal representing a form of the energy pulses expected at the electronic device; and (c) locating and selecting a peak in the correlated signal representing a possible time of arrival of the energy pulse from one of the signal transmitters at the electronic device; (d) from the peak selected in step (c), scanning the correlated signal in a reverse direction of time for sequentially preceding peaks until either (i) a located and selected preceding peak has a magnitude less than a threshold, or (ii) a starting point of a prescribed range of time measured back from the possible time of arrival is reached; and (e) identifying a last-selected threshold-exceeding peak, which has a magnitude value greater than the threshold, as an indication of a true time of arrival of the energy pulse from the one of the signal transmitters at the electronic device.