Aircraft approach and landing system - using phase modulated radio signals indicating aircraft position

摘要

The airport aircraft landing system employs a HF source and at least one associated HF source which is movable relative to the first source in two coordinate directions, with the aircraft having a receiver determining the angular position of the aircraft from the received phase modulated signals. Pref. the antenna system comprises a main antenna (17) extending along an axis (16) and two further parallel antennae (21, 22) at each end (18, 19) of an arm (20) rotating about the latter axis (16). The arm (20) rotates about the axis (16) at a uniform speed and the two ends (18, 19) of the arm are pref. at different distances from the axis (16) so that the respective antennae (21, 22) describe circles of different diameter.