Forecast and Correction of the Orbital Motion of the Space Vehicle Using Regular Quaternion Equations and Their Solutions in the Kustaanheimo–Stiefels Variables and Isochronic Derivatives

Abstract

The regular quaternion equations of the orbital motion of a spacecraft (SC) proposed by us earlier in four-dimensional Kustaanheimo–Stiefel variables (KS-variables) are considered. These equations use as a new independent variable a variable related to real time by a differential relation (Sundman time transformation) containing the distance to the center of gravity. Various new regular quaternion equations in these variables and equations in regular quaternion osculating elements (slowly varying variables) are also constructed, in which the half generalized eccentric anomaly, widely used in celestial mechanics and space flight mechanics, is used as a new independent variable. Keplerian energy and time are used as additional variables in these equations. These equations are used to construct quaternion equations and relations in variations of KS-variables and their first derivatives and in variations of Keplerian energy and real time; the isochronous derivatives of the KS-variables and of their first derivatives and the matrix of isochronous derivatives for the elliptical Keplerian motion of the spacecraft are found, which are necessary for solving the problems of predicting and correcting its orbital motion. The results of a comparative study of the accuracy of the numerical integration of the Newtonian equations of the spatial restricted three-body problem (Earth, Moon, and spacecraft) in Cartesian coordinates and the regular quaternion equations of this problem in KS-variables are presented, which show that the accuracy of the numerical integration of regular quaternion equations is much higher (by several orders) of the accuracy of numerical integration of equations in Cartesian coordinates. This substantiates the expediency of using regular quaternion equations of the spacecraft orbital motion and the quaternion equations and relations in variations constructed in the article on their basis for the prediction and correction of the orbital motion of a spacecraft.