Development of a Modular, OCT 4.0 Compatible Modem for Optical Ground Stations.

Current procurement and development of optical ground terminals (OGT) focus on entire system concepts. Generally speaking, this encompasses the optical telescope, tracking system, and a modem. The modem is a complex part of this system and contains roughly 80% of the requirements levied in the Optical Communications Terminal (OCT) Standard. In response to this, Smart Logic, Inc. proposes a common modem design that can be used across these OGT designs seamlessly integrating into the various OGT architectures. The benefits of this approach will reduce cost and risk in this area of OGT design and development. The modem shall be designed and developed to meet the requirements defined in SDA, Optical Communications Terminal (OCT) Standard Version 4.0.0, 9100-001-09, 06/28/2024. The design concept will be modular with the anticipation of supporting other waveforms and rates as the SDA developmental tranches progress. The basic functionality of this modem will be based on the “Compact Optical Modem for Early Test”(COMET) modem designed, developed, and deployed by Smart Logic, Inc.  The COMET was developed to support the Naval Research Laboratory (NRL) in optical interoperability testing and qualification of optical communication terminals (OCT) for the SDA Tranche 0 Program. Similar modems have been developed by Smart Logic to support the Tranche 1 and the current Tranche 2 programs. The modem hardware will be implemented using a state-of-the-art field programmable gate array (FPGA) to provide the performance and modularity necessary to implement the SDA waveforms and desired data-plane interfaces.