Simulation model and on-ground performances validation of the PAT system for the SILEX program

Abstract

This paper presents a description of the simulation model and the on-ground performances validation of the Pointing Acquisition and Tracking (PAT) subsystem of the european SILEX program (Semiconductor laser Intersatellite Link Experiment).The SILEX scenario is composed of two terminals mounted on low Earth orbit (SPOT 4) and geostationary orbit (ARTEMIS) spacecrafts. Due to the limited laser beam divergence angle (typical intersatellite distance of 45000 km) a very accurate pointing performance is required. The PAT subsystem is in charge of the initialization of link (acquisition), of the tracking of incoming beam and of the pointing of emitted laser beam. Taking into account all disturbance sources (host spacecraft vibrations, electromechanical or optical noises) the pointing performance is less than 2irad over a frequency bandwidth of 1 kHz.In a first part, a short presentation of the retained strategies (phases of the PAT mission, operating modes) and functional architecture (control laws, sampling frequencies) is given.

Broadband Laser Doppler Frequency Shift Emulator for Satellite Laser Communication

“…Satellite laser communication has become one hot topic in recent years due to its intrinsic merits of high data rate, strong immunity to electromagnetic interference, small antenna size and low power consumption [1]- [3]. However, the communication performance suffers from the optical carrier's Doppler frequency shift (DFS), since non-geostationary satellites change their relative positions to other satellites or ground stations quickly.…”