The paper reviews existing methods of spacecraft navigation and attitude control on near-earth orbits, including the methods utilizing earth-based external trajectory measurement stations, global navigation satellite systems, inertial on-board navigation systems and star trackers. The proposed method is based on the obtaining and processing of a set of sky images on-board of a spacecraft that is moving along a near-earth circular orbit. Image processing results are used to fi nd the coordinates, velocity and attitude of a spacecraft in inertial space.

In this paper, we consider the need to assess the influence of the parameters of a linear time-invariant causal system in the processing of quadrature amplitude modulation signals of various positionality and constellation diagram irregularity. We describe the equations that determine the energy balance of a radio line and the total losses arising in route. We have developed mathematical expressions to assess the equivalent energy losses caused by the irregularity of amplitude-frequency and phase-frequency characteristics of the frequency selection filters. We propose a procedure to assess the non-noise losses in the frequency selection filters when designing high-speed radio systems for transmitting the information.

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Purpose of research. Development of a methodology for determining deviations of pilotless aircrafts from a given trajectory in conditions of signals loss from navigation satellites.Methods. The technique is based on functional relationship between deviation parameters of pilotless aircrafts from a given trajectory and changes in longitudinal and transverse parallaxes of overlapping images of the underlying surface due to these deviations. Mathematical description of computational procedures for deviation parameters determination used methods of functions approximation and mathematical processing of measurement results with accuracy estimation of obtained results.Results. A methodology that includes monitoring, assessing the level and determining the magnitude and direction of deviations of pilotless aircrafts from a given trajectory was developed. A system of nonlinear equations describing functional relationship between deviation parameters and changes in parallax of overlapping images of the underlying surface is obtained. Linearization, normalization and solutions of this system of equations by the least squares method were performed. Analytical relations were obtained for a posterior accuracy assessment of the obtained results.Conclusion. The technique provides parameters detection and determination of uncoordinated deviations of pilotless aircrafts from a given trajectory with an accuracy commensurate with satellite navigation methods. The proposed approach makes it possible to reduce the number of processed corresponding points in overlapping images and the dimension of the problem being solved in comparison with known methods. This significantly reduces the level of computational and resource costs, which is of great importance for the use of developed technique on the board of miniature pilotless aircrafts.

The authors analyze the existing ways of blurring elimination. It determines the technique and problem solving procedure of blurring correction in electro-optical scanning systems on board a spacecraft. The proposed technique is implemented at the initial stages of the survey and is based on the optimization of CCD matrix sampling rate according to the maximum of parameters dispersion of brightness image fields. In contrast to the known approaches, brightness differences of adjacent lines of survey route are values to be measured. The results of testing the technique on conditional frames of lines with different degrees of blurring obtained by distorting the signals of a real space image are presented. The authors’ new approach based on the established functional relationship between the level of blurring, survey parameters and errors of their determination was applied for the blurring simulation. The obtained results prove the possibility of reducing the initial blurring of images being formed on board a spacecraft to the magnitude of tenths of a pixel.