### INFORMATION TECHNOLOGIES AND SYSTEMS, COMPUTER TECHNIQUE

SETS OF GMW-LIKE SEQUENCES
FOR DIGITAL INFORMATION TRANSMISSION AND PROCESSING SYSTEMS
Victor G. Starodubtsev

383

Two sets of sequences similar to Gordon-Mills-Welch (GMW) sequences in finite fields GF(2S) for values S=2 mod 4 are presented. Sets of GMW-like sequences are characterized by a five-level periodic autocorrelation and a four-level cross-correlation function. For these sets, the maximum value of the modulus of the mutual correlation function Rmax = (2S/2+1–1) is less than the same value for Gold sequences equal to (2S/2+1+1). The power of one of the sets, FFG1, is equal to half of the sequence period M1 = (N+1)/2 = 2S/2. All sequences of this set are balanced, that is, their weight is equal to V = 2S/2. The power of the other set of GMW- like sequences, FFG2, is approximately equal to the period of the sequences M2 = (N+1) = 2S/2. The sequences of FFG2 set are unbalanced, that is, their weight can take four values V = [2S/2-1(2S/2+1); 2S-1; 2S/2-1(2S/2–1); 2S/2 (2S/2-1–1)]. It is shown that formation of sets of GMW-like sequences with these power and correlation characteristics is possible only for periods N = 63, 1023, 16383, 262143, for which there exist GMW sequences with verification polynomials of degree 2S.

CONDITION FOR CYCLIC CODES CONSTRUCTING
FOR COMPOSITE CODE SCALES OF DIGITAL ANGLE CONVERTERS
Ozhiganov Aleхander A., Pavel Pribytkin

394

The necessary and sufficient condition for cyclic correction codes construction for composite code scales of digital angle converters for a given minimum code distance and the information capacity of the converter, is formulated and proved.

ESTIMATION OF THE SPREAD OF AERODYNAMIC CHARACTERISTICS
IN MULTIFUNCTIONAL AIR PRESSURE RECEIVER
Aleхandеr A. Pavlovskiy, Soldatkin Vyacheslav V. , Soldatkin Vladimir М.

398

The prospects of using a single (integrated) multifunctional air pressure receiver (APR), providing the perception of all the parameters of the incoming air flow necessary to determine the altitude and speed characteristics of the aircraft movement, are substantiated. The requirements for the air pressure perception errors regulated by the aircraft Airworthiness Standards, are justified. The reasons for the technological dispersion of the aerodynamic characteristics of the channels for the perception of air pressure in manufacturing a multifunctional receiver are considered. To quantify the effect of technological dispersion on the aerodynamic characteristics of a multifunctional APR and the measurement errors of altitude and speed parameters in the wind tunnel, studies of a batch of axisymmetric APR manufactured according to the same design documentation and the same technology on the same equipment and passed the acceptance of the QC department according to geometric parameters are carried out. According to results of the study on a certified aerodynamic installation that has passed the next verification, graphs of the change in the aerodynamic coefficients of the total (dynamic) and static pressure of the APR at the air flow velocity of 150 km/h and the change in the angle of bevel of the incoming airflow in the range from 0 to 30° are determined and constructed. The obtained results create prerequisites for identifying requirements for normalization of characteristics and ensuring the interchangeability of axisymmetric multifunctional APR in aerodynamic systems for measuring the altitude and speed parameters of aircraft and other objects of aviation equipment.

### OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

INVESTIGATION OF THE POSSIBILITY OF COMBINING A FIBER-OPTIC COMMUNICATION LINE
AND AN OBJECT MONITORING SYSTEM
Andrej O. Zenevich, Siarhei V. Zhdanovich, Evgeny V. Novikov, Tatiana A. Matkovskaia, Tatiana G. Kovalenko

406

Currently, fiber-optic communication lines have become the main medium for data transmission, and fiber-optic sensors are increasingly being used to monitor the state of various objects, the sensitive element of which are sections of optical fiber with macro-bends. The possibility of combining a fiber-optic communication line and an object condition monitoring system on the basis of a single fiber is shown. It is proposed to use a wavelength of 1310 nm for transmitting information, and 1490, 1550 and 1625 nm for monitoring the state of the object. An experimental setup is proposed, which provides the possibility of simultaneous use of optical fiber for data transmission and information retrieval from the monitoring system. Parameters of the optical fiber macro bends that can be used in the sensors of the monitoring system are obtained. It is shown that macro-bends with such parameters practically do not contribute to additional attenuation of optical radiation at a wavelength of 1310 nm. The maximum number of sensors that can be used in the monitoring system with such macro-bending parameters is determined. The results of the research can be used in the creation of telecommunication systems combined with systems for monitoring the condition of objects.

MEASURING THE PAINT LAYER OPTICAL PARAMETERS WITH A COLORIMETRIC INSTRUMENT
Majorov Evgeniy E.

413

A colorimetric device is presented that determines not only the level of color correspondence between the test sample and the standard, but also provides measurements of optical reflection spectra in the wavelength range λ = 380–760 nm. The device uses special software to calculate, based on spectral data, the color coordinates of the object in a specified colorimetric system. Metal plates painted in white metallic, silver-light gray, silver-green, silver-red, silver-black colors were studied. Spectral dependences of the diffuse reflection coefficient for each sample under study are obtained.

### SCIENTIFIC AND PRACTICAL DEVELOPMENTS

MODELING OF DYNAMIC PROCESSES
IN THE COMPOSITE WINDING DENSITY CONTROL SYSTEM
Aleksey Yu. Kutin, Musalimov Victor M, Mikhail S. Malov

420

Despite the fairly long and successful practice of automating the methods of manufacturing hollow composite products, it is necessary to create a control system for the process of filament winding. The control system must take into account the relationship between the geometric parameters of the winding being created and the parameters of its strained state. In order to correctly account for the properties of the control object, a model of the dynamics of the processes of this method has been developed, subject to changes in the mass of the control object and its moment of inertia. The obtained equations are the basis for creating a control system, where the angular velocity of the mandrel and the increment of the winding radius are used as the control parameter.

DEFINING THE ORIENTATION OF THE STAND PLATFORM
FOR SEMI-NATURAL MODELING OF THE DYNAMICS
OF A NANOSATELLITE RELATIVE MOTION
Vadim D. Meshcheryakov, Nikolaev Peter N., Aleхandеr A. Khusainov

430

A technique for determining the orientation of the stand platform for semi-natural modeling of angular motion dynamics relative to the center of mass of a nanosatellite is proposed. The developed technique is based on the use of a stereo camera consisting of an infrared camera and a color camera of the visible spectral range. Each of these cameras is designed, respectively, for the formation of infrared and color images on processed photographs. The operation of both cameras is based on the use of a system of active optical markers emitting in the infrared and visible ranges. Based on the image taken by the infrared camera, the centers of optical markers are determined using the Hough transform. By the same method, extraneous artefacts are filtered out in the image obtained by a color camera by evaluating the fundamental matrix. After the color of the marker from the color image is determined, this feature is added to the obtained coordinates of the markers from the infrared image. After that, a triple of vectors is formed in the coordinate system of the stand platform and its orientation is determined in the coordinate system of the infrared camera. According to results of semi-linear modeling, the orientation error does not exceed 0.5°.

INFLUENCE OF SIZE DEVIATIONS OF GAS-STATIC SUPPORTS
IN PRECISION MEASURING EQUIPMENT
ON THEIR OPERATIONAL CHARACTERISTICS
Lilia V. Strok, Vladimir A. Kodnyanko, Viktor S. Sekatsky

443

The relevance of using gas-static bearings in moving parts of modern measuring equipment is shown. A mathematical model of a gas-static support with double throttling has been developed, which makes it possible to analyze the effect of deviations in the dimensions of the bearing and its operational characteristics. Recommendations are given for standardizing the accuracy of the outer diameter of the support, the diameter of the location of the throttling holes and the diameters of the throttling holes themselves. These recommendations can be used in the design of moving parts of precision measuring equipment.

CALCULATION OF CRACKS IN METAL STRUCTURES OF TRANSPORT INFRASTRUCTURE FACILITIES
Tkalich Vera L., Mariia E. Kalinkina, Korobeynikov Anatoliy Grigorievich, Pirozhnikova Olga I.

451

An actual approach to solving problems of the theory of cracks related to the so-called “extremal problems of mechanics” is presented. The problem of “brittle fracture” for a flat element in the presence of a rectangular crack in it, is considered. An analysis of the fracture change dynamics is carried out based on a mathematical model in partial derivatives. The calculations are performed with specific parameters of the material, in particular aluminum, of the elastic element and the load. The obtained results lead to conclusion on importance of geometric arrangement of the elastic elements in metal products of objects of transport infrastructure monitoring.