Relative Motion Parameters Estimation of a Non-Cooperative Spacecraft From Visual Information

Abstract

In this work, we consider the problem of determining parameters of the relative motion of a non-cooperative spacecraft (NSC), which is in free uncontrolled motion, based on the results of measuring the distance to this vehicle and its attitude quaternion. The measurements are assumed to be made by some computer vision system (CVS). A specific type of СVS is not considered. It is supposed the CVS measures the distance and attitude of the so-called graphical reference frame rigidly fixed on the NSC. The parameters of relative motion include the distance vector to the center of mass (c.m.) of the NSC, the attitude quaternion of the principal inertia axes of the NSC relative to the CVS reference frame, the attitude quaternion of the graphical reference frame relative to the NSC principal reference frame, the ratio of the inertia moments, the position vector of the c.m. in the graphical reference frame. The problem is solved using a dynamic filter based on the ellipsoidal estimation method. The method implies knowledge of the maximum values of the measurement noise only, the stochastic noise characteristics are not assumed to be known and therefore are not used. The properties of the proposed algorithm have been demonstrated using numerical simulations. The results obtained are supposed to be used in the development, creation, and testing of a navigation system for the rendezvous and docking of a service spacecraft, developed by a group of enterprises in the space industry of Ukraine under the leadership of the Limited Liability Company “Kurs–Orbital”.