Modernization of aeronautical radio communication system for increasing radio channel immunity

The article considers the possible modernization of the well-known aeronautical radio station in order to increase the noise immunity of radio communications. Uninterrupted noise-immune radio communication between the aircraft and the air traffic controller is an important factor in ensuring flight safety. The radio station provides voice (telephone) communication and telecode digital communication, with voice information transmitted in analog format this causes radio interference distorting the transmitted messages. Increased noise immunity can be achieved by transmitting voice information in a digital form, the special noise protection measures relevant only for digital transmission being applied. Antinoise coding and pseudo-random software frequency hopping can be used as the preventive measures. The task was set to investigate the problem of modernizing a well-known aviation radio station with the minimal changes in its configuration. There has been proposed a method providing the digital radio communication with modification of a prefabricated aeronautical radio station. A digital speech signal developing in this case is provided due to the resources of the radio station used to transmit the telecode information. The information transfer rate increases from 16 to 128 kbps, which leads to the increased frequency deviation and, as a result, to the expanded signal spectrum. The noise immunity of the system was also assessed in a communication range of 100 km: the signal power, signal-to-noise ratio, noise spectral density at the receiver input, transmitting antenna directivity were determined. Based on the results of the calculations, it was inferred that due to realizing the proposed measures a manifold multiplication of the required power of the jamming