In-orbit and Networked Optical Ground Stations Experimental Verification Advanced Testbed (INNOVA): The High-performance and Compact Ground-tracking System

The high-performance and compact groundtracking system has been developed for the terrestrial free-space optical communication network facility called in-orbit and networked optical ground stations experimental verification advanced testbed “INNOVA”. It consists of the “dual” 2-axis gimbals, the fine pointing mechanism (FPM), the optical widerange acquisition sensor (WAS), the optical coarse acquisition sensor (CAS), the optical tracking sensor (FPS), the wavefront correction sensor (WCS) and the deformable mirror for the adaptive-optics (AO) function, and the high-performance controller. The FPM, WAS, CAS, FPS, and AO function are unified as the optical module, and its beam-direction is directly controlled by the 2-axis gimbals. A CMOS image-sensor base of InGaAs is commonly applied to WAS, CAS, FPS, and WCS; the acquisition ranges for WAS and CAS are each tuned by the telescope magnification, and the accuracy of CAS and FPS is determined by the focus distance. In the optical module, the beam-direction is aligned to the optical-fiber by FPM based on the measurement signal of WAS, CAS, and FPS. The “dual” 2axis gimbals have the mechanism of the coarse and fine axes for each azimuth and elevation axis. The corporation control between the gimbals and FPM is achieved using the synchronized WAS, CAS, FPS, and WCS signals. Then, 40Gbps digital coherent optical transponder / 10Gbps IMDD optical transponder can be chosen for the free-space optical communication on the system. Keywords—free-space optical communications; precision optical sensors; ground-tracking control system; adaptive-optics module; 40Gbps/10Gbps optical transponder

[1]  Shigeru Murata,et al.  The new tracking control system for Free-Space Optical Communications , 2011, 2011 International Conference on Space Optical Systems and Applications (ICSOS).