Algorithm for implementation of the «third decision scheme» of increasing the efficiency of search and synchronization of difficult broadband noise like signals

The construction of telecommunication networks with a guaranteed level of quality of service involves assessing and ensuring the security of both the networks themselves and information flows from unauthorized access and various kinds of interference, in particular at the 1st (physical) level of the network. In this regard, research in the field of creating recurrent code sequences with improved systemic, correlation, secretive, imitation-resistant properties is constantly relevant. In particular, research in the development and application of derivative nonlinear recurrent sequences, as a central element in the developed theory of the «third decision scheme». Goal of the work is to develop an algorithm for increasing the efficiency of search and synchronization of broadband signals in the form of double derivatives of nonlinear recurrent sequences, which directly uses the features of their code structure, the properties of determinism of their auto- and cross-correlation functions. The results of the research and development of the efficiency of the algorithm for accelerated search and synchronization of broadband complex signals in the form of phase-shift keyed derivatives of nonlinear recurrent sequences, which implements the principles of the «third decision schema» The developed algorithm, based on the use of double derivatives of nonlinear recurrent sequences as wideband signals, can be applied in the construction of promising packet radio networks.

Recurrent relationships for reflection coefficients of electromagnetic wave potential representation modes in manylayered spherical environment excitation problem

In theoretical assessments of the electrodynamic characteristics of multilayer screens of electromagnetic waves, the concept of the input impedance of a wave on the surface of the screen is used [1]. In [2], an approach was proposed that is not based on this characteristic, and direct recurrence relations were obtained both for the reflection coefficient of a plane wave from a multilayer screen and for the coefficient of transmission of such a wave through this screen. In [3], this approach was applied to solving problems of excitation of a layered medium by localized sources. In this paper, we generalize the approach to the case of a multilayer medium with another simple layer geometry (with interface in the form of concentric spherical shells). The solution of excitation problems is based on the representation of the Hertz potentials of waves of electric (magnetic) types in the form of series in spherical harmonics. Each harmonic defines the angular distribution of radially converging and diverging modes of the representation of potentials in layers free from external sources. The recurrence relations for the reflection coefficients of convergent (diverging) modes of representation when sequentially adding interfaces are a consequence of the boundary conditions. One of the equivalent forms of these relations is derived from the condition for the existence of a nontrivial solution of a system of linear equations for the amplitudes of converging (diverging) modes in adjacent layers. The other is based on a simple physical model of the process of interaction of a converging (diverging) mode in a layer with a layered structure, which it covers (which covers it). For a field source inside one of the layers, one can determine the representation of potentials that this source would excite in an infinite medium with permeabilities similar to a layer. The amplitudes of the modes of representation of this «primary» field and the reflection coefficients of the modes of representation from structures at the internal and external boundaries of the layer, found from recurrence relations, determine the amplitudes of the modes of the total field of the layer incident on these boundaries. To determine the amplitudes of the modes of representation of the potentials of the fields in the remaining layers, recurrence relations can also be used, in a certain sense inverse to the recurrence relations for reflection coefficients. If a layered structure is excited by a plane wave (scattering problem), the total field potentials (of the electric and magnetic types) are the sum of radially converging modes in the potentials describing the incident plane wave and radially diverging modes formed by the reflection of these converging mod from structure. With the proposed approach, the complexity of solving the excitation problems of the considered layered structure remains almost unchanged with an increase in the number of layers. In essence, only the number of repetition cycles of the obtained recurrence relations increases. The proposed approach is conceptually simple, the final recurrence relations are physically transparent. The work does not represent the full facilities of the approach. Within the framework of this approach, recurrence relations for the permeability coefficients of multilayer spherical shells of the structure under consideration, recurrence relations during its layer-by-layer formation or formation from several multilayer shells can be found.

Microstrip antenna array with an inclined surface and an increased distance between patches

A new technique for designing a path antenna array with an inclined beam is proposed. It boils down to finding a certain combination of parameters that use the secondary main maxima of the diagram as the main beam and at the same time guarantee the greatest distance between the emitters that does not yet lead to the occurrence of secondary main maxima in the antenna radiation pattern. This simplifies the geometric structure of the antenna, reduces its cost, simplifies the microstrip power system, and reduces the mutual influence of individual elements in the antenna array. To combine the possibility of reducing the radio visibility of the antenna by changing the orientation of the antenna opening while maintaining its emissivity in a given viewing plane, it is possible to implement an antenna with a main beam deviated from the normal. The efficiency of reducing backscattering for the radar range due to the tilt of the antenna outside the operating frequency band of the antenna is investigated. Thus, when mechanically scanning the antenna, due to the fact that the main beam of the antenna array is deviated from the normal, it is possible to achieve a significant reduction in the average backscattering pattern of at least 25 dB. It is known that improving the safety of small aircraft at low altitudes, as well as on take-off and landing sites, is directly related to the introduction of a small weather radar, which warns of the presence of dangerous phenomena along the flight path: thunderstorms, turbulence, and wind. When the onboard radar is operating in thunderstorm or turbulence detection modes, the presence of re-reflections from the Earth's surface can lead to the formation of false areas that are dangerous for flight. You can reduce the likelihood of such false zones by spatial filtering of interference from the ground using antennas with a low level of side lobes in the lower hemisphere. The relevance of the problem of reducing the influence of interference from the ground on the correctness of the wind speed estimation in the weather radar is confirmed by publications. They are focused on filtering interference from the earth's surface in the frequency domain for ground-based weather radars or for airborne radars, but by the main beam of the alignment diagram and the rule of its elevation to avoid touching the ground. The second part of the research is devoted to reducing the influence of re-reflections from the earth on the probability of forming false areas of dangerous weather events in the weather radar. To reduce the impact of interference, it is proposed to install an antenna with an upward tilt.

Global registration by optical radiation of lightning discharges on aboard a low-orbit spacecraft

Registration of the coordinates of lightning by their optical radiation has already been implemented on geostationary spacecraft in the wavelength range of 777.4 nm. However, the algorithms for processing the registered signals, as well as the volumes of information flows, have not yet been sufficiently studied. The choice of the sensor for the global registration of optical radiation of lightning on board a low-orbit spacecraft is substantiated. The prospects of using photodiodes in the difference-ranging method for determining coordinates are shown.The characteristics of lightning detection using matrices and LEDs have been studied. The prospects of using photodiodes in the differential-range-finding method for determining coordinates are shown. It is shown that the registration of optical lightning radiation on board the spacecraft by photodiodes provides the characteristics of detection and false alarms of a higher quality compared with the use of CCD matrices.

Algebraic solutions in determining the coordinates of the radiator by the results of multi-position measurements of field strength

On the basis of the hypothesis of equality of the measured and true values of the amplitude of the field strength, an algebraic solution for estimating the unknown coordinates and the energy parameter of the radiator is obtained. Initially, by compiling and solving a redefined system of linear equations by pseudo-rotation of matrices, the coordinates of the emitter are determined under the assumption of independence of the distance to the reference point from the coordinates of the emitter. Then make and solve the square equation concerning distance to a reference point with the subsequent estimation of coordinates and an energy parameter. The ambiguity of the algebraic solution is resolved by comparing the maximum likelihood functional and choosing the parameters at which its maximum is reached. According to the simulation of a cellular-type system in multiplicative noise, the results of algebraic solutions by the maximum likelihood method and the calculated ones are close, except for a special zone where anomalous changes occur due to the limitations of the coordinate determination method. Algebraic solutions for maximum likelihood estimation provide an increase in the calculation speed of about 500 times. The proposed principle can be used in solving the ambiguity of algebraic solutions in systems of difference-rangefinder type and in the inverse problem of self-positioning of the receiving point by the amplitude of the electromagnetic field of beacons with a known location. The article contains 4 figures, a list of references from 9 sources.

A practical use of experimentally observed changes in air pressure near conductor with electric current

The possibility of practical application of the results of investigations of air environmental pressure changes in the vicinity of a conductor in which electric current flows is shown. The one-to-one match of environmental pressure changes to alterations of electric current can be applied under transfer of a regulated movement to mobile parts of micro and nanodevices. In accordance with the trends in the development of fields science and industry that require precision accuracy, the modes of small controlled movements of working parts are of greatest interest. When the same current pulses are fed into electric circuit of the described device, the rapid alterations of the pressure are well repeated. The correspondence is observed in a wide range of electric current amplitude and pressure values. The observed peculiarities of the pressure change were used for a regulated shift of the miniaturized holder. In the experiments, when the current in the conductor was altered, the air pressure in the pipe changed resulting in the motion of membrane and the holder that was fixed on it. Small shifts were monitored in microscope. For a convenience to watch the movements of the holder, a glass plate with a defect was placed beneath the holder. Upon a start of a current pulse, the pressure in the working pipe volume increased and by the action onto the elastic membrane caused the movement of the holder fixed on the membrane. When the pulse started, the holder rapidly reached a maximal value of the shift. After reaching the maximal value of the shift, the position of the holder remained almost unchangeable. After turning off the current pulse the holder went back to its original position. The controlled motion of the holder shown in the paper is in the range from less than 2 up to 200 microns. At lower values of pulse current amplitudes, the movement of the holder is less. The consistency of the results was determined solely by the parameters of the electric current pulse. The movements less than 1 micron became possible by applying small values of the current amplitudes. The experiment was carried out in which a plastic cylinder with the inner diameter c.a. 8 mm was attached to the tap of the glass pipe. The teflon piston was installed inside the cylinder, with the ability of free movement inside this cylinder. When a series of current pulses were supplied to the electric circuit from a signals generator, the piston made fast reciprocating motions, which could be easily watched visually. The results of the performed investigations suggest the possibility of widespread use of the effect of the fast pressure change of air environment near the conductor upon current alteration for solving scientific and technical problems. It is possible to create new devices, among others for nanotechnologies, which have great advantages in comparison with existing ones. One can obviously predict application for the creation of micro- and nano-instruments what has a great importance up to date. The simplicity of making such instruments lets us consider that the effect of one-to-one match of the pressure change to the electric current alterations in the working camera is prospective.

Security multi-position radar systems: model, topology, structure

In accordance with the general ideas about the relevance, methods and means of protecting important protected objects, as well as the principles of constructing single and multi-position radar systems (radar), the features of radar perimeter protection are considered, with the presentation of it as a large hierarchical system of interconnected, united by a common purpose of functioning controlled subsystems. The measured radar parameters, advantages and disadvantages of security radars, as well as the advantages of multi-position radars over single-position ones are noted. The elements of a mathematical model of a multi-position radar are presented, for which: decomposition of technical protection as a large system; the features of the matrix-vector description of the parameters of the generated and received radar signals of a multi-position radar are considered; analyzed the topology of the security radar as a single object with the protected space; the concept of abstract protected elements is introduced and their relationship with the measure of the protected space in the general case of dimensions longer than three is determined. On the basis of the analysis, the requirements for the structure and placement of the security radar are formulated, which are interdependent on the dimension of the protected area, the topology of the security perimeter, the composition, structure, tactical and technical features of the security radar and tactical, technical, operational, environmental and economic quality indicators. The features of the formation of the structure and placement of single- and multi-position security radars under various initial conditions and requirements, as well as approaches to calculating the coordinates of the placement of their elements on the ground are shown.

Electromagnetic safety: from objects passportization to the state of territories analysis

The development of radio electronic means leads to an increase in the intensity of the electromagnetic field, which can have an impact on human health. In this regard, the urgency of the task of assessing safety by the electromagnetic factor increases. The principles of conducting an examination of electromagnetic safety (EMS) of radio-electronic equipment (REE) for various purposes are discussed in accordance with the requirements of current normative documents, as well as the requirements of ISO/IEC 98: 2008 and GOST R 54500-2011. A number of new concepts are considered, which are prescribed to be used to estimate the uncertainty of the initial data and the new data, as well as the final recommendations for the examination. A number of new concepts are considered, which are prescribed to be used to assess the uncertainty of the initial data and the new data obtained. Recommendations for the examination are given. It is noted that for large urban megalopolises, the transition from certification of individual radio-electronic devices to the compilation of maps illustrating the electromagnetic safety of residential areas is relevant. It is noted that for megalopolises, the transition from certification of individual REE to the compilation of maps illustrating the EMS of residential areas is relevant. The expediency of the transition from certification of REEs to mapping of territories by the EMS factor is shown on the example of examination of a large shopping mall in one of the regional centers of Russia.

Diagnostics of hypersonic plasma by method of intrinsic electromagnetic oscillations of open resonator with non-uniform inclusions

For various areas of radiophysics, plasma physics, studies of spectral and diffraction characteristics of open resonators containing various inhomogeneous inclusions within themselves are of great interest, the material parameters of which depend on spatial coordinates or on frequency parameters of the structure. Approximate models of optical resonators are based on integral equations, the nuclei of which are answered by non-self-conjugated completely continuous operators in some functional spaces (Hilbert or Banach spaces). The rationale for these equations does not seem mathematically correct enough. These equations are derived from the scalar formulation of the mathematically inconsistent Kirchhoff diffraction theory. Therefore, the relationship of these equations with the strict electrodynamic setting of the spectral problem is unclear and, therefore, the applicability of the corresponding models of optical resonators is unclear. The task set forth in the article is to build a strict mathematically justified and effective solution of edge problems about free and forced electromagnetic oscillations for one class of two-dimensional optical resonators with dielectric inclusions. The mirrors of this optical resonator are modeled by a final system of perfectly conductive open circular cylindrical surfaces, and the inclusions by a final system of circular cylindrical regions filled with dielectric medium. The wavelength, geometric parameters of the mirrors of the optical resonators, their mutual location, as well as the dimensions of the inclusions of a priori restrictions are not imposed. The main results obtained are also true for the case of an empty optical resonator that does not contain dielectric inclusions.

Contribution estimation of singular points in solving problems of radiation of HF VHF wire antennas arbitrarily located above the earth

The radiation solving the problem features of the wire antennas placed above the earth are considered. Based on the method of integral equations, the singular points contribution in solving radiation problems of the HF VHF wire antennas arbitrarily located above the earth is researched. The contribution of singular points is estimated depending on the frequency and parameters of the earth. It is shown that in the HF and VHF waves, their contribution of singular points is significant. The radiation solving the problem features of the wire antennas placed above the earth are considered. The value of elements of the Green’s tensor function is usually expressed in the Sommerfeld’s integrals form. The aim of this work is to estimate the contribution of singular points to the value of Sommerfeld’s integrals. Based on the method of integral equations, the singular points contribution in solving radiation problems of the HF VHF wire antennas arbitrarily located above the earth is researched. The contribution of singular points is estimated depending on the frequency and parameters of the earth. It is shown that in the HF and VHF waves, their contribution of singular points is significant.