I. Ya. Orlov - Dr.Sc. (Eng.), Professor of Radio Engineering Department, National Research Nizhny Novgorod State University n.a. N.I. Lobachevsky E-mail: orlov@rf.unn.ru E. S. Fitasov - Ph.D. (Eng.), Associate Professor of Radio Engineering Department, National Research Nizhny Novgorod State University n.a. N.I. Lobachevsky E-mail: fitasoves@mail.ru D. N. Ivlev - Ph.D. (Phys.-Math.), Associate Professor of Radio Engineering Department, National Research Nizhny Novgorod State University n.a. N.I. Lobachevsky E-mail: ivlev@rf.unn.ru S. A. Kozlov - Engineer of 1st category, JSC - Nizhny Novgorod Research Institute of Radio Engineering? E-mail: kozlsergei@yandex.ru

The article considers analysis of the simulation results of the coherence properties of radar signals in antenna arrays based on the evaluation of the signal energy distribution of the eigenvalues of the correlation matrix. The different measures of the degree of co-herence of signals are known, but most of them need apriori information about the signal waveform. The proposed quantitative measure of the degree of coherence of signals in the form of signal distribution entropy among eigensubspaces of its correlation matrix is more universal method comparing existing methods, invariable relative to the signal waveform, universal measure for time and space coherence. The introduced estimate may be realized on basis of the sample correlation matrix without apriori information. The dependences of entropy values of the additive mixture of deterministic sine wave and white noise on the signal-to-noise ratio for various sample lengths and values of the number of antenna array elements have been investigated. In the case of additive mixture of deterministic sine wave and white noise the entropy values approach to some theory value for small values of signal-to-noise ratio. In the case of high value of signal-to-noise ratio the entropy values approach to some minimum value. In the case of value of signal-to-noise approaches to infinity the entropy values approach to zero. The dependences of the entropy values on the difference of the angular directions of the two wave fronts have been presented. The possibility of using of evaluation of the signal energy distribution among the eigenvalues of the correlation matrix for analysis of the coherence properties of radar signals when detection of several closely spaced air targets in the case of orthogonality of the wave fronts. The proposed method of analysis of the coherence properties of radar signals may be applied for radar protection from jamming decoy. One of the most important preferences of this method is possibility of developing of jamming decoy system using only algorithms and programs methods of digital signal processing without changing of antenna characteristics, polarization, signal and impulse characteristics, characteristics of detection and transmission systems.

 

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