| CPC H04W 64/00 (2013.01) [G01S 3/50 (2013.01); G01S 5/0036 (2013.01); G01S 5/08 (2013.01)] | 28 Claims |

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1. A method for location finding, comprising:
receiving radio signals transmitted between a plurality of fixed transceivers having multiple antennas at different, respective first locations and a mobile transceiver at a second location;
detecting a respective phase difference between the received radio signals that are associated with each of the multiple antennas of each of the fixed transceivers;
computing multiple loci corresponding respectively to respective angles between each of the fixed transceivers and the mobile transceiver based on the respective phase differences; and
finding location coordinates of the mobile transceiver based on the angles and the transmit locations of the transmitters by identifying an intersection of the loci as the second location of the mobile transceiver,
wherein the radio signals transmitted over the air between a given fixed transceiver and the mobile transceiver comprise at least first and second radio signals, which are associated respectively with first and second ones of the multiple antennas and are both modulated with a given sequence of symbols, and
wherein detecting the respective phase difference comprises identifying a given symbol in the sequence in each of the first and second radio signals that are received over the air, and measuring a delay in arrival of the given symbol between the first and second radio signals.
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