Performance and characterization results of a lasercom testbed for the pointing, acquisition, and tracking subsystem of a satellite-to-satellite laser communications link

The Aerospace Corporation has developed a testbed for studying pointing, acquisition, and tracking systems for lasercom terminals. The testbed consists of two configurable terminals that are currently set up to represent a GEO-to-GEO link. Each terminal has the ability to point open-loop, execute scan patterns, and track a received beam. The system operates in small-beam space and consists of a far-field space simulator and two lasercom terminals operating at 473 nm and 633 nm with representative hardware (fast steering mirrors, optical detectors, etc.). This paper discusses the software developed for the testbed and the characterization of its performance, which includes open-loop pointing accuracy and residual tracking error in the presence of applied disturbances. Analytical predictions are compared to experimental results. Each terminal has the ability to progress from acquisition to tracking mode and the two terminals together demonstrate the cooperative acquisition process.