The task of wireless data transmission system in electronic conflict is to ensure the secrecy of signal parameters to provide the availability of radio signal in conditions of interference. The task of interference transmitter is to suppress the radio channel with interference. Interference transmitter must explore the parameters of the radio signal to form interference which will be the most effective for its suppression. Increasing structural secrecy of radio signal is aimed at increasing a priori uncertainty of its parameters, and is achieved by manipulating them. An improved method for estimating noise immunity of global navigation satellite systems is proposed in the article. The method allows taking into account the dynamics of the conflict between the navigation system and the interference transmitter: changing signal parameters in time and exploring them. The estimation of noise immunity of navigation signals of global navigation satellite systems allowed to conclude that the use of an increased number of binary quasi-orthogonal code sequences sets will provide high noise immunity of the global navigation satellite system for 15 years.

Increased number of threats to user interface of navigation signals, mainly in the form of suppression of navigation signals by jamming as well as navigation signal spoofing by false signals, assumes development of counter measures including improvement of structure security of navigation signals on the basis of stochastic use of code sequences which are ranging codes. This article proves the required number of unique discrete code sequences which can improve structure security of navigation signal in global navigation satellite system upon their stochastic use. Properties of discrete quasi-orthogonal code sequences are estimated which are used and proposed for use in global navigation satellite systems with channel code division, they are compared with optimum values of code balancing, number of element series and lower bounds of maximum lateral peaks of aperiodic auto-correlation function and maximum peaks of aperiodic mutualcorrelation function. The experimental results show that the minimum values of the considered correlation functions of discrete quasiorthogonal code sequences of known global navigation satellite systems exceed the lower bound by 3-6 times. The performances of code balancing and element series of discrete quasi-orthogonal code sequences of the known global navigation satellite systems satisfy in average the allowable intervals. The number of source lines of discrete quasi-orthogonal code sequences of the known global navigation satellite systems is significantly lower than their umber required for improvement of structure security of navigation signal based on their stochastic use. On the basis of the revealed drawbacks of the known discrete quasi-orthogonal code sequences, the necessity to develop new methods is substantiated allowing to obtain their required number together with statistic properties comparable with the best values of discrete quasiorthogonal code sequences applied as navigation signals in global navigation satellite systems.Keywords: Global navigation satellite systems with code channel division; structure security of navigation signals; stochastic use of binary quasi-orthogonal code sequences.

The objective of the article is to develop the structure of a system for transmitting information with code division of channels and stochastic usage of systems of binary quasiorthogonal code sequences obtained on the basis of functional transformations of pseudo-random arguments, as well as a description of the principle of its functioning. The aim of the article is to develop a method for transmitting information in satellite communication systems and global navigation satellite systems with code division of channels and stochastic usage of binary quasiorthogonal code sequences obtained on the basis of functional transformations of pseudo-random arguments, providing an increase in structural secrecy. The elements of novelty are obtaining a new structure of an information transmission system with code division of channels and increased structural secrecy, as well as a description of the main stages of the information exchange method based on this system. The method differs from the known ones by stochastic use of binary quasi-orthogonal code sequences obtained on the basis of functional transformations of pseudo-random arguments. The main result of the article is that the presented method of information transmission makes it possible to reduce the impact of deliberate imitating interference and cases of substitution of the signals used by increasing the structural (signal) secrecy of the information transmission system with code division multiplexing and stochastic usage of systems of binary quasi-orthogonal code sequences.

The article solved the problem of finding analytic dependency showing the influence coefficients of the second diagonal Hermitian matrix by correlation and spectral properties defined by it in the amplified sense of orthogonal signals. The analytical dependences between the coefficients of the second diagonal of the Hermitian matrix and the correlation and spectral characteristics of ensembles of discrete orthogonal signals in the amplified sense are determined. The use of formulas allows for specific selection of ensembles orthogonal in the amplified sense signals, which reduces the time of synthesis. When the values of the diagonal coefficients modules are constant, the arguments of these coefficients do not affect the values of the modules of the unit elements of sets of discrete orthogonal signals in the amplified sense. The value of the eigenvector arguments of a two-diagonal Hermitian matrix is determined by the arguments of its diagonal coefficients. Correlation functions of signals with equal values of modules of unit elements are determined only by the values of their arguments. For certain ratios of modules and arguments of coefficients of second diagonal Hermitian matrix and corresponding minors can be obtained the required levels of lateral peaks of the correlation functions and the values of the relative effective width of the spectrum of the synthesized ensemble of discrete orthogonal in the amplified sense signals.

The article describes the influence of lighting on the accuracy of users authentication in access control systems on the iris. The low contrast of the iris image is the reason that increases the number of errors because of different lighting at the stages of registration and authentication of the user. Depending on the wavelength of light in which the iris is registered, various details appear on it, and their severity depends on the type of eye. Most light eyes give the clearest picture in visible light. On the contrary, the structures of dark eyes clearly appear in the infrared range. It is recommended to use an iris biometric authentication system with the functionality of visible and infrared scanning ranges. Then the system should evaluate the quality of the images obtained in the visible and infrared scanning ranges and select the best quality. This lead to the addition of a new step in the recognition algorithm, which increases the running time of the algorithm as a whole. To compensate the time required for that, it is recommended to use an optimal set of modules of residual classes system, which will improve the performance and technical characteristics of digital filters.