The objective of this activity is develop an optical ISL breadboard, based on the re-engineering / adaptation of existing optical ISL equipment used for communications, suitable for MEO Radio navigation Satellite Constellation and SatCom Constellations (LEO or MEO) covering inter-satellite data transmission, inter-satellite ranging and inter-satellite time and frequency transfer.
Improvement of the terminal acquisition and repointing capabilities to improve network and data management. Improvement of the Satellite Orbit Determination and Time Synchronisation for Radio navigation Systems.
Space optical communicationshas experienced a significant growth in interest with important research and development efforts, various in-flight demonstrations and space operational systems already making use of it. In the field of inter-satellite links, optical technology provides clear advantages in terms of bandwidth for data transmission, confidentiality and time transfer. Inter-satellite links are also of growinginterest and use in SatCom Constellations (LEO or MEO) and also in Satellite Radio navigation Systems. For SatCom Constellations inter-satellite data transmission, but also inter-satellite ranging are vital for effective network management, which includes also ranging and time synchronisation capabilities. Frequent repointing may be required for large constellation systems.
For Radio navigation Systems there is a distinct use case for intersatellite links: Improvement of the Satellite Orbit Determination and Time Synchronisation. This normally requires the collection of the inter-satellite ranging and on-board clock data between one satellite and a subset of the rest, gathering sufficient constellation-level observations within few minutes, which may be later blended with other ranging and clock observations.
The scope of this activity is to develop an optical ISL breadboard (consisting of one optical terminalEngineering Model and two optical counter-terminal Breadboards), based on the re-engineering of existing optical ISL equipment usedfor communications, also suitable for MEO Radio navigation Satellite Constellation covering the following use cases: Frequent inter-satellite ranging, in and across plane, for improvement of Orbit Determination and Time Synchronization, through a fast switching of the inter-satellite link. Inter-satellite data transmission (to exchange for instance telecommand and telemetry, mission data andranging/clock observations from other satellites). Inter-satellite Time and Frequency Transfer.
The objective is to demonstrate that a compact optical ISL solution can be (re-) engineered based on prior heritage to fulfil the GNSS and SatCom Constellationssystem needs. The specific targets are as follows: Optimise pointing and acquisition of the inter-satellite link down to the 10secondrange, with a minimum slot (bi-directional for ranging and data) duration per link of ca. 30 seconds. Maximise ranging accuracy and time and frequency transfer performance of the inter-satellite link. Data rate up to 10Gbps for SatCom Constellations and higher than 1.5Mbps for Radio navigation Satellite Constellations. Maximum power of approx. 150W and Mass below 30kg. Reliability 0.99 for a lifetime of 13years (cold redundancy maybe proposed in case reliability cannot be fulfilled by a single optical terminal) for Radio navigation Satellite Constellations. Cost optimization for SatCom Constellations. Demonstration in an on-ground testbedwith hardware-in-the-loop for different geometrical configurations (i.e. adjustable baseline and orientations emulating in-orbit frequent inter-satellite ranging) Secondarily, assessment of the capability to support ground-to-space communication and ranging forIn-Orbit Testing indicating the ground station requirements and its feasibility. Assessment of the capability to support in the future a demonstrator for Quantum Key Distribution for satellite-to-satelllite and ground-to-space.