Position determination of resident space objects via triangulation with two passive-optical staring systems

Abstract

The number of space objects orbiting the Earth is rapidly increasing. An opportunity to detect and measure the position of space objects are passive optical staring systems, e.g. our system called APPARILLO. While staring systems are capable of measuring highly accurate equatorial coordinates of space objects via an astrometric calibration, they do not provide information on their altitude unless the space object is assumed to fly on a circular orbit. In this work we discuss an approach in which the altitude of a space object is measured via triangulation (simultaneous observation with two staring systems placed at different positions on Earth). Based on theoretical calculations, we estimate that the triangulation with two staring systems can provide the altitude of a typical space object in a low Earth orbit with an accuracy as low as 200 m. This is two orders of magnitude better compared to a simple circular orbit approximation that can be used for a single staring system.