Method for the prediction of the frequency of airborne high-frequency circuits at high-altitude and long-distance communication

Abstract

During the test flight of civil aircraft, the prediction method recommended by ITU-R P.533 was used to predict the frequency of the high frequency(HF) system at the situation of the high-altitude and long-distance communication. There were many cases which the communication effect was lower than the design expectations. Through comparative analysis of test flight scenarios and scenarios recommended by ITU-R P.533, it is found that the flight altitude of the aircraft is a key factor affecting the accuracy of frequency prediction, and the communication distance will also exacerbate the impact of flight altitude. This paper establishes the test flight model of the airborne high frequency system to obtain the correction amount of flight altitude and communication distance for the frequency prediction. It proves the correctness and effectiveness of the method discussed in this paper through multi-scenario test flights.