A method of preliminary solution of the problem of space robot navigation based on the results of measurements carried out using its onboard optronic equipment is presented. The initial data of the navigation problem are the directional cosines of the space robot orientation vector in the absolute geocentric equatorial coordinate system with reference to time during one revolution. Analytical expressions are obtained for determining unknown parameters of the motion of the space robot center of mass in the form of Keplers elements of the orbit. It is shown that to determine the right ascension of the ascending node, the inclination and the semi-major axis of the orbit of the space robot, information about the orientation of its radius vector at various times is used, and to determine the perigee argument, the moment of passing the perigee and the eccentricity of the orbit, the angular orbital speed of the space robot is used, which is determined by the results of evaluating the speed of change in the orientation of its radius vector over time. The presented results can be used in the development of software for navigation systems that allow autonomous determination of the parameters of the space robots orbit using onboard electro-optical sensors in the absence of a priori information about the parameters of the reference orbit or signals from satellite radio navigation systems.

The results of comparative estimation of the accuracy of autonomous navigation of small spacecraft in formation flying are presented. To carry out the research, the “zenith” method and the method of navigation by orbital references were chosen. These methods are based on measurements of the angular position of the Earth and an orbital reference point relative to navigational stars. Assumptions concerning the central terrestrial gravitational field and the normality of errors of the on-board navigation measurements with known constant variability were introduced in the studies. The studies were carried out using the theory of analytical estimation of the accuracy of spacecraft autonomous navigation methods. The use of this theory makes it possible to obtain the covariance error matrix of the required vector of navigation parameters and to estimate the potential (maximum achievable) characteristics of the accuracy of the navigation methods used. A dimensionless navigation error coefficient was chosen as an indicator of the accuracy of small spacecraft navigation method. The coefficient is associated with the elements of the main diagonal of the covariance matrix, it characterizes the precision properties of the method, is integrated by nature and does not depend on the volume and accuracy of the results of navigation measurements. The criterion of expediency of applying the method of determining the parameters of motion of the spacecraft center of mass is based on the comparison of navigation error rates. The presented results allow us to make reasonable choice of the method of autonomous navigation and of the composition of the onboard control of small spacecraft in formation flying.

Рассматривается метод оценивания точности системы автономной навигации космического аппарата, заключающийся в определении аналитическим путем ковариационных матриц погрешностей навигации, полученных на основе изме-рений, производимых адаптивным бортовым информационно-измерительным комплексом при наличии возмущающих факторов космического пространства. Исследование процессов и принципов функционирования бортовых систем управле-ния космических аппаратов (КА) связано с определением целесообразности использования новых технических решений по созданию перспективных систем автономной навигации. В ходе этих исследований решается комплекс задач, одной из которых является анализ по-тенциальной (предельно достижимой) точности определения параметров движения центра масс КА при выбранных составах датчиков первичной навигационной информации (да-лее -датчики).Для проведения аналитических исследований точности систем автономной навигации (САН) КА используются детерминированные и стохастические методы, разработанные в рамках научной школы под руководством проф. Л. Ф. Порфирьева и представленные в моно-графии [1]. При этом объективная информация о характеристиках точности исследуемой САН КА формируется с помощью стохастического метода начального оценивания, который получил развитие в работах [2][3][4][5].В результате применения этого метода можно аналитическим путем найти ковариаци-онную матрицу погрешностей навигации КА, т.е. матрицу-вектор па-раметров движения центра масс КА в момент времени 0 t , который соответствует началу мер-ного интервала навигационного режима:

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An analytical solution to the problem of determining the parameters of motion of an orbiter’s center of mass is presented on the basis on the results of measurements carried out using the optical system of a space robot located in orbit coplanar to that of the orbiter. The “space robot-orbiter” line-of-sight angle and the line-of-sight rate in the moving orbital system of coordinates of the space robot are selected as initial parameters that are measured by the space robot’s on-board optical system. Along with the known orbital parameters of the space robot they are used to solve the problem of determining the parameters of motion of the orbiter’s center of mass. When solving this task, assumptions are introduced concerning the central gravitational field of the Earth, the coplanarity of the orbits of the space robot and of the orbiter, absence of influence of the atmosphere, the moon's attraction and the pressure of the solar wind on the motion of the space robot and of the orbiter, absence of errors in the results of measurements performed by the space robot’s on-board optics. Analytical expressions are obtained to determine the unknown parameters of motion of the orbiter’s center of mass. The results presented can be used to develop methods allowing standalone determination of parameters of the orbit of unknown orbiters using on-board optics of a space robot.