Морфологический подход к измерению временных параметров сигналов малозаметных РЛС по их частотно-временным портретам

Low probability of intercept (LPI) radars have the property of low power, wide bandwidth, frequency variability or other design features to make them difficult to be detected or identified by passive intercept receiver devices such as radio engineering complexes (RTK). In the RTK the potential error of time parameters measurement is determined by fluctuations in the signal fronts. With a small signal to noise ratio, the separation of the pulse fronts becomes practically impossible. In this connection, a contradiction arises which is associated with the need to estimate the time parameters of signals of low-visibility radar with an SNR of less than 0 dB on the one hand and limitations of existing methods on the other hand. One of the possible solutions to this contradiction is the measurement of time parameters using algorithms for morphological processing of the results of bilinear time-frequency distributions, for example Choi-Williams distribution. The purpose of the research was to provide the possibility of automatic estimation of signals time parameters in conditions of low SNR (less than 0 dB) using algorithms for morphological processing of the time-frequency distribution results. To achieve this goal the imitation model of the estimating process of the time parameters (for example, the pulse duration) was developed. The simulation was carried out in the Matlab R2016a environment. The proposed approach for estimating the time parameters of signals under conditions of low SNR (less than 0 dB) is based on the application wavelet thresholding and morphological processing in a new subject area. The developed simulation model allows providing the possibility of automatic estimation of signals time parameters. This approach can be used to jointly assess the frequency and time parameters of signals from LPI radars.