Optical Modem System

About The Optical Modem System

The Celestia STS Multi-Mission Optical Modem facilitates optical satellite communication, supporting data rates up to 10 Gbps. Compatible with multiple standards, the system is suitable for both optical ground station (OGS) integration and test environments. It consists of three primary modules: the Optical Modem unit, the Optical Front End (OFE), and the Workstation/ Data Ingest Server

Front Optical Modem Celestia-STS C-STS
Optical Modem and Optical Front End Celestia STS C-STS

Optical Modem Unit
The Multi-Mission Optical Modem Unit enables versatile satellite communication by supporting a wide range of standards, including CCSDS and various SDA specifications (2.1.2/EAGLE-1, 3.0.1, 3.1.0, and 3.2.0), as well as proprietary protocols. Featuring in-field re-configurability, the 19-inch rack-mountable unit is specifically engineered for integration into optical ground stations (OGS). Additionally, it can serve as a test instrument for lab-based validation of free-space optical communication space terminals.

Optical Front End
The optical Modem System provides flexible input and output configurations to meet site-specific requirements. The Optical Modem System is fully adaptable to the specific needs of the station and its connected satellites. The highly scalable Optical Front End (OFE) features a downlink interface with options for one or two single-mode or multi-mode receivers of up to 2.5 Gbps or 10 Gbps. The uplink interface supports standard one or optional two tuneable C-band optical transmitters designed for simultaneous operation on the same channel with a user-definable wavelength offset, typically ranging between 10–15 GHz. Additionally, the system includes a programmable digital skew feature on the data lines to compensate for downstream fiber and optical path variations.

Workstation/ Data Ingest Server
The Optical Modem System is managed via a workstation running the C-STS Control and Monitor software, which provides both a local Graphical User Interface and a Remote Interface (RIF). This LAN-based RIF enables seamless integration with an Optical Ground Station’s (OGS) overall control software, allowing the modem to function as a “black box” system. Additionally, an optional Raw Data Ingest Server can be supplied to save hard-decision data bits directly to disk. This powerful feature enables clients to analyze or process raw, unprocessed data using either C-STS tools or custom proprietary software. By providing transparent data recording, the system allows for flexible, non-standard offline processing of all data captured during a satellite pass.

Key Features

  • Standard compatibility: SDA 2.1.2/EAGLE-1, SDA 3.0.1, SDA 3.1.0 and SDA 3.2.0, CCSDS O3K RS Branch, custom proprietary standards
  • Multiple tuneable optical Tx outputs with programmable skew (optical C-band)
  • Powerful receiver for very low optical input powers
  • FC/APC input and output bulkhead connectors
  • 10Gbit LAN for data ingress/egress
  • Control and Monitoring software included

Data Processing

  • Hardware processing of digital bitstream from optical receiver
  • Bitstream decoding, FEC decoding and data extraction
  • Designed for baud rates of up to 11.3 Gps
  • Ingest raw data to disc: browse and process
  • Internal BER test data generation: PRBS or custom from file
  • Internal loopback tests: optical and electrical

Equipment Details

The Optical Modem System typically connects to the OGS optical bench via fiber, where optical transmit and receive data are processed directly by the Modem. For user data ingress and egress, the system provides a 10G LAN TCP/IP interface. To support test and validation, the modem includes a built-in test generator capable of producing PRBS patterns or loading user-defined test data from files, supporting both optical and electrical closed-loop testing. While the modem can connect directly to a customer’s existing ingest or processing system, Celestia STS also offers a dedicated server platform for local data storage. Furthermore, the Optical Modem is highly adaptable; it can be configured as a standalone data receiver and processor without the Optical Front End, and vice versa, to meet specific requirements regarding data handling and OGS requirements. Each Optical Modem System is delivered with comprehensive back-end software for control, monitoring, and data archiving

Information, specs & downloads

Download Optical Modem brochure

Heritage

The original Optical Modem was called the Optical Digital Converter (ODC) and was released in Q2 2019 while implementing the project of Optical Ground Station in collaboration with TNO (Netherlands Organisation for Applied Scientific Research). During implementation the ODC has been validated with several satellite optical terminals including the EAGLE-1 and Hyperion Technologies CubeCAT Laser communication module.