By Karen Craigmyle.
In today’s world, we’re accustomed to having a seamless flow of data surrounding us at the touch of our fingers. Wi-Fi, 5G mobile phone connectivity, high speed internet, laptops, and television broadcasts for example are a range of applications and examples of how technology invisibly shapes our lives.
Frequently, we hear about spectacular rocket launches and deployment of sophisticated satellites into space to satisfy this demand for data. Beyond these spacecrafts, the ground segment is just as an essential part of the satellite communication network infrastructure. It is responsible for delivering these technological breakthroughs to the market, where cost, optimisation, and compatibility with the next generation of LEO satellites must be taken into account to give connectivity to space.
At Celestia UK we are designing and developing antennas to support ultra-high throughput satcoms. Our electronically scanned phased array antennas offer significant advantages over mechanically steered antennas, such as a smaller footprint and greater efficiency, and greater reliability (since there are no moving parts, compared with the motor system of a large parabolic dish).
Given the increasing number of Low Earth Orbit (LEO) satellites, gateway antennas which are electronically steerable, and have multi beam capabilities are increasingly desirable to maximise the data transferred to these satellites will minimising the area of land used to locate the antennas.
In this article, we will explore some the technologies Celestia UK is utilising to advance innovation in the space sector. Looking at the role played by the technology no-one sees – all the work, thought, and design that goes on behind the scenes that’s invisible from the outside but necessary to bring any improvements to market.
Satellites are deployed into space and have very directional antennas, that must be compatible with the ground antenna. Successful links between the satellite and the ground antenna rely upon compatibility between the antenna on the satellite and on the ground.
Additionally, there is a need for frequency coordination of constellations of satellites; different frequency bands are tailored for specific applications, and so there is a significant effort required in ensuring adherence to different regulations, and regulatory bodies that the satellite and ground segment must take into consideration.
Ground segment, Gateway Antenna and System testing
In addition to the space segment which involves deploying and operating satellites in space with varying orbits and frequencies, the ground segment is an equally critical part of the infrastructure, ensuring that the RF signals from satellites in space, are managed in such a way that communication flows through the network seamlessly.
The ground antenna is responsible for transmission and reception of these signals and relaying them through the rest of the communication system network. Antennas are fundamental in capturing, conditioning, and amplifying these signals. Unlike a personal antenna such as a TV dish on the wall in your home, a Gateway antenna manages much larger amounts of data from multiple users, with signal management supported by the underlying ground network.
Antenna and System testing
These gateways follow an incremental build-up process, starting with the integration of lower-level components and sub-systems, leading up to operation of the full system.
A gateway antenna must be reliable and operate and perform even in challenging conditions such as snow and wind. In order to ensure that this happens, it is necessary to build a confidence in the system, and therefore a thorough test campaign must be carried out. Testing of the system performance needs to be repeatable and reliable and under controlled conditions.
At Celestia we are fortunate to have several anechoic chambers, which we use to test our antennas and systems. These chambers can be configured to test different frequency types, and different polarisations. The chambers also have software to measure Key Performance Indicators and parametric data e.g. power, gain, axial ratio etc.
An anechoic chamber blocks out electromagnetic signals to provide a ‘quiet’ environment (i.e. no unwanted reflections) which allows the test engineers to analyse the performance of the antenna in end use representative environment. The test allows us to test in a controlled and repeatable way without interference. An anechoic chamber is invaluable when it comes to testing the capabilities of electronic beam steering and simulating the tracking of a LEO satellite pass.
When we are happy that the antenna system is performing as expected and we have completed as much comprehensive testing as possible in the anechoic chamber, we will take the antenna system into open space and perform field trials, during which we can demonstrate successful links with the satellite in transmission and reception.
Working at Celestia UK
The work we do here at Celestia UK is incredibly rewarding, as we play a pivotal role in advancing society through innovation in a thriving Scottish satellite communications and space industry.
The work is very satisfying as we deliver important innovation to society within a rapidly growing sector in Scotland. Our diverse team encompasses a wide range of roles, including test technicians, software and hardware engineers, radio frequency experts, mechanical engineers, and project managers.
We have a dynamic team of over 30 professionals based in Edinburgh, with collaborative connections extending to Portugal and Spain.
About the author
Karen is the Principal Systems Integration Engineer at Celestia UK. She gained a BSc Honours in Mathematics at the University of Aberdeen, and then completed an MSc Satellite Communications Engineering degree at the University of Surrey. She has over 20 years’ experience of multi-disciplinary projects in Satellite communications, Radar Systems, and Ground Antenna systems. In her current role at Celestia UK she is leading the integration and testing of electronically scanned Antenna Gateways and the support required for on-site installations.