A free-space laser communication system for bidirectional transmission of telemetry data in Gigabit Ethernet (GBE) protocol using a dual atmospheric effect mitigation approach. This free-space bidirectional GBE laser communication system utilizes an Optical Combining Receiver Array and a Framer/Forward Error Correction/Interleaver (FFI) device to mitigate the combined effects of atmospheric turbulence and channel fading. Since the FFI device is designed for Synchronous Optical Network (SONET) protocol, an intelligent (or smart) media converter is used to convert GBE telemetry data to SONET frames, which enables the FFI device to perform an error correction algorithm and provide a seamless error-free GBE laser communication link for distance over a kilometer. This bidirectional laser communication system can be implemented with low-cost commercially available components.

System for bidirectional free-space laser communication of gigabit ethernet telemetry data

A method for pointing control of a laser communication terminal on a spacecraft may include measuring a line-of-sight (LOS) error of the laser communication terminal. The method may also include estimating a LOS error of the laser communication terminal based on measurements from a spacecraft gyro and a gimbal gyro onboard the spacecraft. The method may further include switching from a LOS error measurement feedback to a LOS error estimate feedback to control pointing of the laser communication terminal during a power fade condition.

Ketao Liu

Papers

Gyro-aided pointing control for laser communications