Frequency Efficiency Evaluation of Query Airspace Surveillance Systems

In this work, there was carried out an evaluation of frequency efficiency of both the interrogation signal channel and the response signal channel in case of intra-system and intentional (correlated and uncorrelated), as well as fluctuation interference. The evaluation based on the representation of interrogation radar systems for observing airspace in the form of two-channel systems for transmitting information of interrogation signals and response signals. It is shown that the use of interrogation signals and response signals in the form of an interval-time and positional code leads to the need for a significant receiving path bandwidth expansion of both the aircraft transponder and the interrogating radar system as a whole. This caused by the requirements for obtaining sharp edges of the received signals, which is necessary for decoding them and leads to a significant decrease in the frequency efficiency of the considered information systems and, as a consequence, to a decrease in the noise immunity of both the request channel and the response channel of the considered information systems.