The Doppler Twin Beacon

This radio aid to navigation differs from conventional radio beacons in the use of two spaced antenna arrays giving two separate directional radiation patterns. Preconditions and feasible solutions for the spatial separation of the arrays are shown. The use of the Doppler principle with its swing vs direction patterns permits transmission of the azimuth information independently of the carrier amplitude. This mode of operation precludes the disadvantages due to inhomogeneities in the two propagation paths established in the previously proposed split-antenna systems.