The data acquisition function is fulfilled by Acquisition Service in the form of operational service provision.

The CSC Acquisition service is tailored to the technical baseline of each CSC satellite family and includes in particular:

• X-Band Acquisition service, in line with the Sentinels satellite downlink operations technical baseline
• EDRS Acquisition service, in line with the Sentinel-1 and Sentinel-2 satellites downlink operations technical baseline
• Ka-Band Acquisition service, foreseen to fulfil the needs of some Expansion missions

Multiple Ground Stations may be necessary to jointly fulfil the acquisition needs of a given satellite unit and in any case, multiple Ground Stations are necessary to fulfil the overall acquisition needs. The same Ground Station may serve one single or several Sentinel missions, depending on its acquisition capacity and the various mission needs. Each Acquisition Ground Station contributing to the CSC acquisition operates autonomously with respect to the others, the allocation of downlink operations for each Ground Station being performed by the Mission Planning system of each Sentinel after being de-conflicted by the Sentinels Resource Allocation (SRA) system.

X-Band Acquisition

The scope of the X-Band Acquisition function is defined with the aim of minimising the need for Copernicus specificities (e.g. hosting, e.g. processing to Level-0 data). Accordingly, the functional scope is focussed on the Copernicus missions data acquisition, data downconversion, demodulation, satellite CADU data stream generation and delivery. Multiple Acquisition Ground Stations are necessary in the GS architecture to jointly satisfy the downlink needs of all flying missions. Each Acquisition Ground Station operates autonomously with respect to the others, the allocation of downlink operations for each Ground Station being performed by the Mission Planning system of each Sentinel after being de-conflicted by the

Sentinels Resource Allocation (SRA) system. The same Ground Station may serve one single or several Sentinel missions, depending on its acquisition capacity and the various mission needs.

EDRS Acquisition

The EDRS service covers the following functions:

• Regular definition of the EDRS Links available for the data downlink planning.
• Optical Sentinel-EDRSGEO Link operations and Ka-Band Sentinel payload and HKTM data acquisition based on associated link schedule, including down-converter and demodulation
• Generation of Sentinel CADU data stream for the scheduled passes
• Transfer of generated Sentinel CADU stream to the EDRS Interface Point
• Maintenance of the EIP, ensuring its availability for consumers and handling of the CADU rolling policy

The EDRS Acquisition is a Sentinel-1 and Sentinel-2 element.

EDRS downlink visibilities are settled by the SRA in interface with the EDRS Mission Control Operations (MOC) and used by each Sentinel mission planning as part of the available downlink resources, together with the X-Band available passes.

Ka-Band Acquisition

The observation requirements of the Copernicus missions currently in operations (i.e. Copernicus Sentinel-1,2,3,5P,6) are compatible with a downlink of payload data in X-Band. In contrast, the increased volume of data generated by some of the Copernicus Expansion (COP EX) missions requires Ka-Band to fulfil the demanding downlink capacity.

The COP EX missions will also implement the CFDP protocol for the transmission of the payload data between the satellite and the ground.

The scope of the Ka-Band Acquisition function is identical to the X-Band Acquisition function and it covers the following functions:

• Regular retrieval of station scheduling information from the Mission Planning Interface Point, as made available by the mission planning element.
• Ka-Band acquisition of Sentinel satellites payload and HKTM data based on associated acquisition schedule, including down-converter and demodulation (HKTM is downloaded in every orbit in Ka-Band).
• Generation of Sentinel CADU data stream for the scheduled passes.
• Transfer of generated Sentinel CADU stream to the Ka-Band Interface Point (CADIP) within required timeliness
• Maintenance of the CADIP, ensuring its availability for consumers and handling of the CADU rolling policy

The Ka-Band Acquisition is a common element for the Copernicus missions: The functional scope of the Ka-Band Acquisition is defined in order to be generic and fulfil the acquisition needs for all flying Copernicus missions requiring the Ka-Band downlink operations.