The new stare & chase procedure at the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald

Abstract

The need of precise orbits of resident space objects to prevent collisions suggests the use of laser-ranging measurements for orbit determination and improvement. A major technical challenge is due to the rather small field of view of the laser if compared against other optical systems. Therefore, the lack of precise ephemerides poses a problem for the direct use of the Satellite Laser Ranging system (SLR). The Stare & Chase method attempts to bridge this gap by correcting the pointing of the telescope using a night-tracking camera. The aim of the current work is to determine the minimum requirements, in terms of number and type of observations needed to chase the object with the laser. In particular, the analysis is divided in two main steps. The first is to find the minimum number of measurements needed to generate ephemerides, after an orbit determination procedure, that will allow the tracking of the object within the same pass. The second step of the analysis is developed in order to find the portion of passage to be observed to ensure the re-acquisition of the object during a subsequent pass over the station. So that one can perform, once more, the Stare & Chase procedure to further improve the knowledge of the orbit of the object. All analysis are performed using real data acquired by the SLR system and the night-tracking camera of the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald (SwissOGS).