METHODS AND MEANS FOR PROVIDING IMPROVED AIR/GROUND RADIO TELEPHONE COMMUNICATIONS

摘要

The present invention relates to an aircraft radio telephone receiving apparatus for selecting the best signal from a group of signals transmitted from space to ground stations based upon signal strength and detected Doppler frequency errors of the received signals from the spaced ground stations. The apparatus includes controls for tuning of the receiving means to the frequencies transmitted from the ground stations, signal strength measuring circuitry for determining the signal strength of each of the received ground station signals, measuring circuitry for the polarity and magnitude of the Doppler frequency error of each of the ground station's signal and comparing circuitry for the measurement of the ground station signals provided by the Dobbler frequency error and the signal strength defined above. This apparatus takes into account the strength of the signal presently received as well as a measurement which allows the assessment of whether the signal is likely to improve or deteriorate in the immediate future due to the aircraft's path of travel. The apparatus and method of the present invention provide a simple solution without the need for communication with the navigational equipment of the aircraft or other vehicle.