Design and Development of a Laser Fine Pointing Sensor

Abstract

Mission concepts that require high precision formation ying as gravitational wave ob- servatories or future geodesy missions rely on accurately determining the position (and/or accurately tracking) of a target satellite. The complexity of the pointing (tracking) sensor is related to the mission's requirements and the system's design. In this paper, a �ne point- ing sensor concept that avails on a laser link is presented. The sensor is designed to operate in the frequency range from 2 to 16MHz as it can be used in a heterodyne or homodyne con�guration. The sensor architecture integrates a �ne pointing mechanism to steer the laser beam and a quadrant photodiode to detect and track the target satellite. Signal lock is achieved using digital phase-locked loops hosted in a �eld programmable gate array. The robustness of the digital phase-locked loops in detecting the incoming laser signal has been tested with a heterodyne interferometer setup while other instrument's components have been tested using dedicated testbeds.