Vol 53, No 1 (2017)

Various aspects of mathematical modeling of the inclination parameter converter based on two double-axis accelerometers in a single integrated design are considered. Possible variants of design patterns of such a converter are presented. Additional turns of the accelerometer sensors mounted in the converter body are considered. Generalized static mathematical models for two double-axis accelerometers as part of the inclination parameter converter are obtained, which ensure accurate determination of the spatial orientation angles of an object: zenith and sighting (apsidal) angles.

A problem of control of quadrotors in a leader–follower formation is considered. A method is proposed, which allows control actions for the follower robot to be formed only on the basis of information about the follower motion parameters and the relative positions of the leader and follower.

This paper presents a method using a two-position system to determine the spatial coordinates of a moving radiation source from one bearing measurement and relative energy measurements of the received signal taking into account the effect of its reflection from the Earth surface. The passive location problem is solved for low elevation angles taking into account the curvature of the Earth and using a polynomial model of source motion. An algorithm for the parametric identification of this model using a measurement sample of increasing size in a regularized formulation is developed, and the accuracy characteristics of the method are analyzed.

The phenomenon of four-wave mixing in passive optical networks with wavelength-division multiplexing of channels has been studied. This paper presents the results of modeling the distribution of combination frequencies over the spectrum as a function of the number of channels and the channel frequency spacing. To suppress crosstalk between the channels at combination frequencies, it is proposed to divide the spectrum into two parts and select a guard band between them. The effect of combination frequencies on the signal transmission quality is considered as a function of the channel power, channel frequency spacing, and transmission length.

Computer simulation was performed for the measurement process of the parameters of MIOL-Akkord bifocal diffractive-refractive lenses in which the central area of the diffractive element is reduced and spherical aberrations of the eye are compensated. The spatial-energy characteristics of an ideal diffractive lens are preliminarily calculated using existing formulas. The simulation of the process of controlling the intraocular lens parameters has shown that the intensity distribution along the optical axis does not characterize the diffraction efficiency, which is the total (integrated) intensity in the beam cross section at the focus. It has been found that due to the mutual influence of diffraction orders, it is difficult to measure the absolute diffraction efficiency and it is better to evaluate only the relative efficiency.

This paper shows that the near-surface layer of a lithium niobate single layer 15 μm in depth is essentially different from the rest of the volume of the material from the standpoint of composition, structure, and mechanical properties. The pointed out differences are due to the effect of cutting, polishing, and smoothing of the lithium niobate plates, which increase the density of point defects and dislocations. The increasing density of the structural defects leads to uncontrollable changes in the conditions of the formations of waveguides and the drifting of characteristics of integrated optical circuits. The results obtained are very important for the manufacture of lithium niobate based integrated optical circuits.

This paper describes the stochastic models of electron-hole recombination in inhomogeneous semiconductors in two-dimensional and three-dimensional cases, which were developed on the basis of discrete (cellular automation) and continuous (Monte Carlo method) approaches. The mathematical model of electron-hole recombination, constructed on the basis of a system of spatially inhomogeneous nonlinear integro-differential Smoluchowski equations, is illustrated. The continuous algorithm of the Monte Carlo method and the discrete cellular automation algorithm used for the simulation of particle recombination in semiconductors are shown.