Acquisition and tracking control of satellite-borne laser communication systems and simulation of downlink fluctuations

Abstract

Fluctuation in the intensity of a downlink ͑satellite-to-ground͒ laser beam is examined by first measuring the acquisition time and pointing error of a satellite-borne laser communication system. The downlink intensity fluctuation is then simulated using a computer model that takes into account the effects of acquisition and tracking control, satellite attitude perturbation, and intensity fluctuation due to atmospheric turbulence. The simulation shows that when the tracking control-loop is closed, the major portion of the angular variation due to satellite attitude variation is corrected by the tracking control; scarcely any angular error in beam pointing remains.

Atmospheric tip/tilt compensation for laser beam tracking with amateur telescopes

“…The receiving optical efficiency η(0,0) is expressed by The impact of the platform-induced beam jitter and laser pointing stability were previously measured [1]. The noiseequivalent angle (NEA) is the angle of detection error caused by noise or beam jitter of the position detector, and it is a measure of the performance of laser tracking systems.…”

“…Laser beam tracking systems are important add-ons for high resolution image stabilized observations, for minimizing the signal fading effect in the field of optical free space communications [1] or to focus energy over long distance in highpower laser effectors. They are being used to eliminate system vibrations and to compensate for long-range atmospheric turbulence effects.…”

Study on Robust Control Technology of Opto-Electronic Tracking System

“…The mathematical model of the speed loop motor and the load is The controller of the speed loop adopts lead-lag compensation in the classical control theory [3]. It is designed by frequency characteristic method and its transfer function is…”

A real-time sub-μrad laser beam tracking system

“…Using a secondary tip/tilt mirror Japanese astronomers [4] successfully stabilized a XUV telescope mounted on a rocket to within 1.4 µrad to overcome the limited pointing accuracy of the rocket system. Laser beam tracking activities are also known in the industry (laser machining tools), medical section (eye trackers) and communication fields (free space laser communication) [5,6].…”