MATHEMATICAL MODEL OF A SIGNAL WITH SPECIFIED POLARISATION PARAMETERS IN THE ORTHOGONAL POLARISATION BASIS

The experience of combat operations in the context of the large-scale invasion of Ukraine by the russian federation shows that the current level of development of electronic weapons is characterised by a wide variety of types and types of electronic means, the use of multifunctional means with widely variable signal parameters and operating modes. For example, modern (state-of-the-art) ground, air and sea radar stations use deliberate changes in the frequency, time and polarisation parameters of emitted signals in different modes of operation, depending on the tasks and conditions of a complex electronic environment. The presence of differences in the polarisation parameters of signals objectively creates prerequisites for their consideration in processing in order to improve the detection, recognition and direction finding performance of radio monitoring systems in a complex electronic environment. The approach is based on the use of antennas with orthogonal polarisation antenna elements, which allows signals to be represented as polarisation vectors. During the processing, it is necessary to take into account the influence of the polarisation characteristics of the antenna system on the parameters of the polarisation vector (change of the polarisation basis), which is relevant since the signals are received by the antenna system from different angular directions. An important condition for obtaining objective results when studying the efficiency of polarisation processing algorithms is the use of a correct mathematical model of signals with given polarisation parameters in a certain orthogonal polarisation basis, as well as the use of signals from real radio equipment whose polarisation parameters can be determined in a polarisation basis other than the specified one. The article presents a mathematical model that allows expressing the field components through the parameters of the polarisation ellipse, and also gives expressions describing the relationship between polarisation vectors and their covariance matrices in different polarisation bases of the antenna system.