Initial Orbit Determination Method for an Unknown Resident Space Object with a Matched Velocity Magnitude Association in the Frame Plane

The paper presents a method for solving the problem of initial orbit determination of an unknown resident space object based on a limited number of angular measurements. The angular measurements were obtained from a matched detection of the unknown object with an estimation of the velocity magnitude in the frame plane within two pointing regions of the optical system. Based on the estimated velocity magnitude, two position radius vectors were calculated, which were subsequently used to determine the velocity vector and orbital parameters of the unknown space object. The proposed method allowed the unambiguous computation of the orbital parameters of the Indefix/Ariane 42P satellite (NORAD: 27422) with an angular precision of up to 0.7 deg. in the inclination, longitude of the ascending node, and argument of latitude determination and an error in the determination of the semi-major axis of less than 27.5 km.