Авіаційно-космічна техніка та технологія (Nov 2020)
PECULIARITIES OF PROCESSING AND DELAY ESTIMATION FOR RANDOM WIDEBAND SIGNALS IN NON-GAUSSIAN ENVIRONMENT
Abstract
Peculiarities of operation conditions of methods and tools for assessing delay and angular position of the source of a random wideband signal when it is received by two spatially displaced sensors are analyzed. Special attention is paid to modeling of possible non-Gaussian noise and analyzing its effect on estimation results. It is assumed that digital processing of received signals is carried out in intervals of certain duration (parts of a second). The first feature is that, unlike many other applications of cross-correlation processing of received broadband signals or their analogs, the information component is characterized by possible nonstationarity both in terms of power and, accordingly, the signal-to-noise ratio, and spectral composition of oscillations. The second feature is that both due to possible low signal-to-noise ratios in some areas, and as a result of non-Gaussian noise, that usually has a distribution with heavy tails, abnormal estimates of the delay, and angular position of a source are possible. In such situations, it is desirable to apply a method for estimating the delay of random broadband signals, which will be robust to non-Gaussian noise and exclude abnormal estimates or at least to the maximum extent reduce the probability of their occurrence. The purpose of this work is to study the possibilities of using other measures of similarity and analysis of processing efficiency. It is shown that this can be achieved due to the use of methods based on the calculation of robust distances. The efficiency of various modifications of the proposed method is shown depending on the intensity and impulsivity of the noise. Following various criteria, the efficiency of processing is assessed and the need for automatic obtaining of information about the noise characteristics is shown. The studies are carried out using a test wideband signal. The tasks that must be solved first of all to ensure a high efficiency of processing are formulated. The results obtained in the simulation process can be used in many technical fields, where the processing of the received signal in hard noise conditions is kept.
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