Patent ID: 8704712

Claim:
A system configured to provide a combined transmission, the system comprising: a plurality of circumferentially-located antennas; a reference antenna located centrally to the plurality of antennas; and a radio frequency generator unit coupled to at least one of the plurality of circumferentially-located antennas, the radio frequency generator unit configured to: generate a primary signal for driving at least one antenna of the plurality of antennas to provide a primary transmission; apply the primary signal to at least one of the plurality of circumferentially-located antennas to transmit the primary transmission; generate a secondary signal actively-derived from the primary signal to compensate the primary signal and reduce, at least in part, an antenna radiation pattern distortion of the primary transmission; and apply the secondary signal to at least one other antenna of the plurality of circumferentially-located antennas adjacent to the at least one antenna to provide, collectively with the primary transmission, a combined transmission having a reduced observed distortion at a receiving device compared with an observed distortion of the primary transmission alone, wherein the combined transmission allows the receiving device to calculate a navigational indicator relative to the plurality of circumferentially-located antennas.