A Method for Constructing the Trajectory for an Unmanned Aerial Vehicle in a City
A synthesis method for the reference trajectory of an unmanned aerial vehicle that flies around obstacles of urban buildings in the horizontal and vertical planes is proposed. To solve this problem, for the first time a conformal mapping is constructed for a collection of rectangles that approximate the obstacles on the digital map of a terrain.
The research is to develop tabular-analytical and tabular-approximating methods of altitude evaluation statistics calculations according to a digital height map. The subject matter is the comparative evaluation of the relief height statistics calculations methods. The analysis of mathematical expectation and height dispersion method errors by means of tabular-approximating method is provided. The aim is to increase the accuracy of flight altitude evaluation according to a digital height map while counting prognostic flight path by means of on-board inertial navigation system. As a result of a numerical experiment using the tabular-analytical method the following boundary values of errors are defined: the maximum error of mathematical expectation does not exceed 0,3 meters for a mathematical expectation evaluation and 0,25 meters for root-mean-square deviation of relief height evaluation. The research results allow recommending the tabular- approximating method for practical use during low-altitude aircraft flight echelon formation. Also it is necessary to pointout the fact that the needed computing resources do not depend on planned coordinates errors during a fixed flight time.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.