OpSTAR - Optical Synchronized Time and Ranging
Laser terminals have revolutionized space communication, with Germany in the leading position. DLR Institute of Communications and Navigation has been looking at ways to significantly advance the operations of a GNSS by introducing this optical technology into the navigation domain with the proposed Kepler system architecture.
The OpSTAR mission aims at in-orbit demonstration of optical inter-satellite links to autonomously synchronize satellite clocks, obtain accurate inter-satellite ranging to improve orbit determination, and exchange data with low latency and high throughput. OpSTAR will also be a testbed for validating the system and processing architecture of a GNSS fully integrating optical inter-satellite links for more robust and accurate global navigation and timing services.
In February 2025, the European Space Agency ESA has contracted phases A and B1 of the OpSTAR In-Orbit Demonstrator to a consortium led by OHB Systems including DLR Institute of Communications and Navigation and more than 30 European companies from more than 12 countries.
ESA
Our contribution
The role of DLR Institute of Communications and Navigation in OpSTAR focuses on
- the development of optical elements enabling synchronization and ranging functions over optical links,
- the design and operations of optical ground stations and
- a system synchronization testbed to verify operations and performance of the envisioned autonomous satellite synchronization system.
Further, DLR Institute of Communications and Navigationis is involved in the definition and design of novel system and processing architectures to advance Position, Navigation and Timing (PNT) services based on GNSS equipped with an optical payload. System-level performance analyses will be enabled by an accurate software-based simulator to jointly process optical and L-band observations.
OpSTAR architecture
The OpSTAR In-Orbit Demonstrator (IOD) is formed by four main elements:
- a space segment of two MEO satellites, each supporting an optical payload comprising of two or more optical terminals, and a navigation payload to broadcast navigation L-band signals;
- a ground optical testbed, consisting of two optical ground stations, a data processing facility and all necessary interfaces for accurate timing synchronization and its verification;
- a mission control center, handling all routine operations of the two OpSTAR satellites, providing support for mission execution and experimental verifications;
- an end-to-end GNSS system simulator for extrapolating and assessing GNSS and user performance.
High-level OpSTAR mission goals
With the proposed OpSTAR IOD, simultaneous bi-directional optical links will be established between two MEO satellites and a number of dedicated optical ground stations..
The OpSTAR IOD aims at achieving the following mission objectives:
- demonstrate the use of optical inter-satellite links and optical ground-to-space links with embedded Position, Navigation & Timing capabilities;
- demonstrate the benefits of optical PNT technology with respect to state-of-the-art GNSS for system and end user performance;
- assess the system-level benefits for a fully optical Global PNT system enabled by optical links utilizing the OpSTAR IOD assets;
- contribute to the development of (European lead) open standards for optical PNT links (physical, data link and network layers) for space systems;
- demonstrate the improved system resilience and long-term autonomy enabled by Optical PTN technology;
- contribute to the demonstration of a multi-layer PNT system of systems.
A successful execution of the OpSTAR IOD mission will pave the way to the transition towards a multi-layered navigation system (such as Galileo or LEO-PNT) with significantly enhanced capabilities in terms of signal-in-space quality, reliability, resilience, and overall system operability and performance.
Projects
In the Kepler Vision project, the Institute of Communications and Navigation is refining the Kepler concept and continuously developing it according to requirements defined by the relevant institutions.
With Kepler, the Institute of Communications and Navigation has presented a system proposal for a 3rd generation global satellite navigation system (GNSS) – enabling significant navigation performance improvements compared to current GNSSs.
In the COMPASSO project, the Institute of Communications and Navigation, together with the Galileo Competence Center and the Institute for Quantum Technologies, is testing several optical elements (optical clocks and frequency combs) in low-earth orbits aiming at raising the TRL via a technology demonstration mission.
OpSTAR in ESA FutureNav program: ESA - ESA to develop optical technology for navigation
More information
Article on OpSTAR in the magazine “InsideGNSS”
https://lsc-pagepro.mydigitalpublication.com/publication/?i=851733&p=52&view=issueViewer )