Evaluation of Satellite’s Point-Ahead Angle Derived from TLE for Laser Communication

Abstract

AbstractAdvances in lasers, optics and electronics for Satellite’s optical communication are opening the possibility of very high performance near Earth space links with data rate up to several Gbps. Being the divergence of the laser beam typically of tens of $$\mu$$ μ rad, an extremely high precision pointing is needed to correctly establish and maintain data optical link. In particular, the relative motion between the satellite and the ground station shall be accurately evaluated to estimate how to correct pointing angles for future orbital locations. This correction is made via a point-ahead mirror (PAM) mechanism, which deviates the laser beam by an angle called point-ahead angle (PAA). The purpose of this paper is evaluate the possibility of accurately estimate the point-ahead angle in advance using the two-line elements sets for the orbiting satellite, which are available before the ground station overpass. The study evaluated TLE-based orbital evolution of Sentinel-6 satellite, comparing the results with the high precision data obtained by laser ranging from the crustal dynamics data information system (CDDIS). The maximum error observed between the estimated and measured point-ahead angles was less than 1$$\mu$$ μ rad, demonstrating the possibility of this point-ahead correction technique for LEO orbiting satellites.