Application of system analysis to find the optimal structure of a nonlinear frequency–modulated signal in radar air traffic control systems

A decrease in the effective reflection surface of modern aircraft, especially small-sized ones, is one of the technical features of modern design solutions and can lead to a significant decrease in the quality of air traffic control, and, consequently, to a decrease in flight safety. Solving the problem of detecting and locating small targets is significantly complicated by the interference situation in the area of a modern airfield. The article presents an analysis of the most well-known existing approaches to the formation of a nonlinear frequency law for broadband frequency-modulated probing radio signals, which, while maintaining the principle of phase stationarity, minimize the level of side lobes of the matched filter response in the primary processing system on the receiving side. Such signals have improved correlation properties and provide an effective solution to the problems of detecting, resolving, and evaluating target motion parameters in ground-based radar systems and air traffic control systems. In the final part of the article, the requirements for new synthesized signals with nonlinear partial modulation are formed in the interests of achieving the required qualitative and quantitative characteristics, such as: the level of the side lobes of the uncertainty function, the width of its main lobe and the level of distortion of the signal spectrum with a Doppler shift of the target.