Non-cooperative target positioning and tracking algorithm based on bearings only measurement

With the vigorous development of space technology, positioning and tracking of non-cooperative target become an important problem within the domain of space surveillance and safety. Because of the perturbation effect, orbital plane changes with time in the inertia frame, then the real position and velocity vector beyond the plane which is spanned by initial position and velocity, so the classical Laplace model is not suit for the dynamics model with perturbation forces. With consideration of perturbation effect on the normal direction of orbit plane, in this paper, the Laplace model of spacecraft motion was extended and founded in the space which is spanned by position vector, velocity vector and the multiplication cross vector of both, then a new tracking algorithm of non-cooperative target was studied based on bearings only measurement. Results show that non-cooperative target could be well tracked and positioned only with bearings measurement when the number of tracking devices is equal to or greater than two, so the new method could be used in the domain of space surveillance and invade target early warning.