Abstract: An electronic navigation beacon, particularly for coastal navigation, in which an unmodulated carrier f.sub.c is transmitted from the first antenna of a pair of antennas, and a periodically modulated sideband f.sub.c .+-.f.sub.a is transmitted from both antennas, where f.sub.a is in the audio frequency domain. A cyclical RF phase variation is imposed on the sideband signal transmitted from the second antenna. The effect in space is that of a rotating radial having an audio frequency null, the periodic modulation providing the listener at a remote point with timing information enabling determination bearing as a function of the time of passage of the radial through the remote point relative to the start of rotation of the radial.

Abstract: A system involving a mechanically or electronically scanned beam of electromagnetic energy and separate antenna means for transmitting a phase reference signal. A remote receiving station, such as on-board an aircraft on landing approach, is able to process received signals coherently to take advantage of the increased accuracy available in such processing.

Abstract: A Doppler Navigation Beacon incorporating the moving reference concept in a planar antenna matrix with programmed excitation, replacing the linear commutated array of the prior art to provide vertical diversity for azimuth guidance use and horizontal diversity for vertical guidance use. A pencil-beam effect is obtained without change of signal format or receiving station processing. Technique applicable to Doppler type navigation (landing) systems and to direction finding generally.