This article discusses approaches to connecting space-based assets to a ground station network. It was produced in collaboration with ground station network operator Leaf Space, a participant in the satsearch membership program.
In many ways a small satellite is only as valuable as the data it sends back to Earth. Unless the test and demonstration of the launch aspect was your primary goal, without an accurate and predictable way of communicating with a spacecraft it may as well be an expensive cube-shaped rock stuck in Earth’s orbit for a few years!
Every year we’re seeing new sensing, propulsion and control technologies for smallsats come to market, opening up affordable opportunities for manufacturers and mission designers. But these new sub-systems require effective data up- and down-links, and a modern ground segment solution, if the full value is to be gained.
Ground station services are a sector where innovation in recent years has dramatically simplified the demands on satellite operators, particularly through the development of shared networks. In this post we discuss shared satellite ground station networks and how a satellite operator can connect to one, using the example of Leaf Space’s Leaf Line network.
The power of the ground station network
A ground station network is a distributed collection of existing (and proprietary for Leaf Space) ground station facilities and antennae spread around the world. It is accessed through a single, consistent system that provides value-added coverage for Earth-satellite data exchange.
A shared ground station network brings several distinct advantages compared with developing a bespoke solution:
- The costs, time commitment and resources needed are substantially less with an existing network. There is no need to develop and deploy antennae around the world or build the data infrastructure needed to access your satellite – just plug straight in to optimised resources that are already up and running.
- Shared ground station service providers are responsible for your datalink’s uptime and quality on an ongoing basis, ensuring that the service is uninterrupted and operates as required. This is particularly important in the event of outages or failures.
- New improvements and cutting-edge innovations in the sector are more likely to be assessed, tested, deployed and seamlessly integrated into an existing satellite ground station network by a specialist partner with a commercial incentive to run the best possible operation.
In addition, for companies unable to develop their own ground segment a ground station-as-a-service is imperative for applications that require enterprise-level security and reliability for the network. This is particularly important for commercial ventures.
When to plan the ground segment during mission design
It is important to consider which ground control station solutions will work best for the mission very early in the design process.
The type of communications equipment required needs to be carefully chosen to achieve mission goals (minimising weight and volume) while also working effectively with the satellite ground segment solution needed to control the satellite and access your data.
In addition, although a shared network such as Leaf Space’s Leaf Line is a simple and highly scalable option, there is a small investment of time and resources required so that everything can get up and running seamlessly. Adding a ground station solution at short notice could result in the mission not achieving its full potential in terms of data access, or worse, cause a delay in launch.
However, advancements in interoperability and software mean that is possible to access the Leaf Line network if your satellite is already in orbit under certain conditions.
In addition, one of the ways that Leaf Space has worked to minimise the setup requirements and simplify mission planning is in the pre-integration of radios. Thanks to the SDR-based ground stations, a number of common radio models have already been integrated by developing and deploying specific DSP software patches on the shared network, so that satellite developers using these products can get up and running faster and for lower costs.
The following radios are pre-integrated in the Leaf Line service (with further models in development which will soon be integrated):
| Radio | Manufacturer | Frequency | Modulation |
|---|---|---|---|
| SR2000 | GomSpace | 2025-2120; 2200-2290 | QPSK |
| AX100 | GomSpace | 140-144; 399-403 | GFSK/GMSK |
| SRS-3 | Satlab | 2025-2110; 2200-2290 | GMSK |
| Li-1 | AstroDev | 137-144; 399-403 | FSK/GMSK |
The setup process
Connecting a satellite to a ground station network is a straightforward process that can be carried out at various stages of a mission’s planning and development (though the earlier the better, as explained above).
We’ve broken down the main steps that customers typically follow to get up and running on the Leaf Line network, which are broadly similar to comparable services.
Step 1 – determine initial requirements
Firstly, you need to know the main specifications of the service that your satellite or constellation will require. This will include details such as:
- Your company details and personal contact information
- Details of currently orbiting satellite or planned mission and launch timings
- Satellite(s) orbits
- Primary satellite functions, data exchange and transceiver requirements
In addition, it will be very helpful if you understand what frequencies would be most suitable for your mission’s needs. The Leaf Line network includes ground stations that can operate in the following frequencies:
Step 2 – refine solutions
Once the service provider has received your initial set of requirements there will be a process of discussion and refinement of the solution between you and the engineers responsible for overseeing the network.
This is a vital part of the process. As a mission designer you are probably clear on your specific coverage and pass timings/frequency but it will help to discuss all the options with the ground segment network provider.
You might find out that there are alternative or additional setups that could add new capabilities and capacity to your mission with little or no extra cost or resource, maximising your investment.
Leaf Space has found for example that many missions don’t require ground antennae based at the poles, which can lower costs and simplify ground network requirements.
Step 3 – integrate mission
Once the requirements are understood and all necessary equipment is up and running, your mission can then be integrated into the satellite ground segment network (potentially including integration of the transceiver protocols in the SDRs used for the ground station network, if they are not currently supported by Leaf Space’s ground station network).
This stage will enable you to further tweak and refine the parameters of your ground segment use for your particular needs.
Step 4 – testing
Once integration is complete the next task is to test the entire service, either on the ground or with the satellite in orbit.
Both the up- and down-links (where relevant) will be tested as well as your access to the data that the ground station network acquires and secures on your behalf.
This is an opportunity to calibrate your mission control and management software systems to work optimally with the incoming data.
Step 5 – activate
Now all systems are ready for use and you are good to go!
Once your satellite is launched (or re-calibrated if already in orbit) you will then be able to access your data according to the requirements and schedule that you have agreed with the service provider.
And if your requirements change during the mission’s lifetime, it is possible to scale the service up or down as needed enabling you to react and respond to the exciting opportunities that space is bringing to us all.
To find out more about Leaf Space and see the details of the Leaf Line shared ground station network service, please view their supplier page here on satsearch.