gs4EO ground segment is built using a combination of 4EO products, working in a coherent and synchronized way, although all of them can also be used as independent applications. Each application communicates with the remaining GS using file based interfaces, easing its integration with other external solutions.
Each of them is controlled by means of advanced user interfaces, in many cases web-based, and can be operated remotely. They are also highly configurable, using XML files.
Their main characteristics of gs4EO can be summarized as follows:
- State-of-the art.
- Proven operationally at ESA
- Flexibility. Scalability. User Friendly.
- Designed for maximising S/C return
These products are already being used in different ESA and Spanish Governmental missions, like plan4EO or monitor4EO, used by Sentinel-2, of archive4EO, process4EO and calval4EO in Ingenio/SEOSAT, and all of them are the basis for the Ground Segment of our own missions, DEIMOS-1 and DEIMOS-2.
DEIMOS-2 Ground Segment includes the complete on-ground facilities to control, monitor and commercially exploit the mission.
DEIMOS-2 Ground Segment is developed according to the following main drivers:
- Limit the GS development and operation costs ensuring that the required mission objectives can be fulfilled by relaying in standard and open source components when possible.
- Use DEIMOS’ know-how and expertise from previous Earth Observation projects and studies. Re-use existing DEIMOS’ assets.
- Create an integrated system that can be operated with the minimum number of personnel and as automatic as possible.
- Implement an open and flexible architecture to ensure its expandability and its portability to future missions, as well as its integrability with external applications
It has been developed using the gs4EO suite of products.
Figure 1: Deimos-2 Ground Segment High Level Architecture
Thanks to its modular design, the gs4EO suite of products can be used to customize the ground segment according to the customer’s requirements: various individual products can be assembled in different ways to implement different deployment configurations. This modularity also provides extraordinary flexibility in order to accommodate more than one Earth Observation mission in the ground segment, with different levels of integration.
The deployment shown above is the most typical set-up of all the GS elements, providing all the ground segment capabilities required by the mission. With this solution, customers would mainly access the S/C resources via the User Services, and all data downlink and processing would be performed in the single “central” ground segment (CGS).
It is possible to provide customers with their own Ground Stations and/or Data Processing and Archiving capabilities. Here we find different increasingly complex ground station concepts that can be summarized in two main categories: a VRS (Virtual Receiving Station) or a DRS (Direct Receiving Station).
The Virtual Receiving Station (VRS) is a system conceived for customers who do not have a receiving antenna, or do not want to receive data of a specific satellite. In this scheme, the acquisitions can be planned by the customer, but the data is downloaded at the “central” premises (e.g. DEIMOS ones), and then delivered as fast as possible to the customer. Processing can be done at customer or DEIMOS premises, depending on the selected option.
The Direct Receiving Station (DRS) is a full-fledged ground segment conceived for customers who have a receiving antenna. In this scheme, the acquisitions can be planned by the customer, data is downloaded at customer premises, and can then be processed and archived within the user ground segment.
There are different levels of integration between the User Services and Mission Planning systems of the VRS/DRS and the Central Ground Segment. In its most basic solution, the customer will use the user4EO at its premises, to perform feasibility studies, identify possible acquisitions opportunities, and request (via e-mail) the images to the operator’s CGS. The next step is to use the advanced user4EO module, allowing the operator to perform image acquisition request assessment with automatic connection to the central plan4EO system that will provide automatic feedback about the request acceptance and status.
In the most advanced solution, the customer is provided with a complete User Services and Mission Planning system that would allow the customer to, based on the commercial exploitation agreements, have full freedom in the use of the allocated S/C resources. The customer system is of course connected to the CGS Mission Planning where a highly sophisticated optimization algorithm is used to ensure the customer agreements are fulfilled, maximizing the overall mission return.
Figure 2: Advanced Direct Receiving Station
Many gs4EO components have multi-mission capabilities that allow the integration within the GS of third party missions. The clearest example is the inclusion, within the VRS or DRS of other satellite acquisition and data processing chains. The archive component allows the storage of data from different satellites and the integration effort will depend on the specific interfaces of the third party missions. Typically:
- Interface with the third party Central Ground Stations, to send acquisition requests, get G/S pass schedule, and receive orbital and other auxiliary (e.g. calibration) data. Although user4EO is designed to include new S/C with relative low effort, it is also possible to accommodate third party user services and adapt interfaces to connect to other VRS/DRS 4EO components (e.g. catalogue). track4EO can support multiple downlink requests from different S/C.
- Interface with the data processors. Although process4EO implements standard interfaces at ESA, it might be needed some encapsulation and modifications to trigger the third party processors.
- Interface between S/C and G/S, that may require dedicated HW
The following is an example of integration with another mission:
Figure 3: Multi-mission Direct Receiving Station (DRS)