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The Small Optical Ground Stations Focal-Optics Assembly (SOFA)

Knopp, Marcus Thomas and Immerz, Andreas and Giggenbach, Dirk and Köhler, Alexander (2022) The Small Optical Ground Stations Focal-Optics Assembly (SOFA). In: IAC 2022 congress proceedings, 73rd International Astronautical Congress (IAC), Paris, France. 73rd International Astronautical Congress (IAC), 2022-09-18 - 2022-09-22, Paris, Frankreich.

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Official URL: https://dl.iafastro.directory/event/IAC-2022/paper/68520/


Due to an ever-increasing demand for bandwidth and capacity, the microwave spectrum has become a highly limited resource in satellite communications. Therefore, free-space optical communication is being deployed in operational space systems like the European Data Relay Satellite system. Besides, laser-based space-to-ground connections will complement radio downlinks in upcoming Earth observation and science missions allowing for data rates in the 10 to 100 Gigabits per second range. To make the latter a success, a large number of Earth-based receiving stations, so-called Optical Ground Stations (OGS), will be needed, as the mitigation of cloud coverage requires the implementation of a site diversity scheme. On this backdrop, we have developed a fully-integrated, low-cost instrument as a supplement to standard telescope optics, transforming astronomic observatories as well as commercial off-the-shelf (COTS) portable telescopes into optical ground stations – the Small OGS Focal-optics Assembly (SOFA). In the SOFA, pointing, acquisition and tracking functionality is implemented by low-resolution machine vision allowing for arcsecond-level accuracy in combination with COTS telescope mounts. Free-space detection of the laser downlink signal is realized with both a large area Positive Intrinsic Negative (PIN) diode for power assessment and a small area Avalanche Photodiode (APD) for data reception. All sensors make use of the telescope optics’ primary beam path obviating the need for elaborate co-alignment systems, hence, mitigating the associated boresight offsets. The SOFA concept is based on a modular design allowing for expansion with further components like laser beacons or different detector variants. Here, we present the opto-mechanic SOFA arrangement and its prototypic implementation by additive manufacturing at an amateur-grade astronomic telescope. Upcoming campaigns are geared to demonstrate its functioning for the reception of optical downlinks from low Earth orbiting (LEO) spacecraft carrying laser communication terminals of the DLR Institute of Communications and Navigation.

Item URL in elib:https://elib.dlr.de/192151/
Document Type:Conference or Workshop Item (Speech)
Title:The Small Optical Ground Stations Focal-Optics Assembly (SOFA)
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Knopp, Marcus ThomasUNSPECIFIEDhttps://orcid.org/0000-0002-6819-6279UNSPECIFIED
Köhler, AlexanderUNSPECIFIEDhttps://orcid.org/0000-0001-9759-1166UNSPECIFIED
Date:20 September 2022
Journal or Publication Title:IAC 2022 congress proceedings, 73rd International Astronautical Congress (IAC), Paris, France
Refereed publication:No
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:Free-space optical communications, direct-to-Earth laser links, optical LEO downlinks, optical ground station, laser communication
Event Title:73rd International Astronautical Congress (IAC)
Event Location:Paris, Frankreich
Event Type:international Conference
Event Start Date:18 September 2022
Event End Date:22 September 2022
Organizer:International Astronautical Federation (IAF)
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Communication, Navigation, Quantum Technology
DLR - Research area:Raumfahrt
DLR - Program:R KNQ - Communication, Navigation, Quantum Technology
DLR - Research theme (Project):R - Project Global Connectivity - HAP [KNQ], R - Responsive Space
Location: Oberpfaffenhofen
Institutes and Institutions:Responsive Space Cluster Competence Center
Institute of Communication and Navigation
Responsive Space Cluster Competence Center > Ground Segment
Deposited By: Knopp, Dr Marcus Thomas
Deposited On:19 Dec 2022 12:08
Last Modified:24 Apr 2024 20:53

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