Calibre Interview: Helen Weedon, Satcoms Innovation Group

Calibre Defence met with the Satcoms Innovation Group to gain a deeper understanding of satellite communications (Satcoms) and the key issues the group identifies for the coming years.

Satellite communications (Satcoms) are a critical element of modern warfare, whether providing urgent updates to a carrier strike group operating far beyond the reach of high-frequency radio in the Indo-Pacific, or controlling uncrewed ground vehicles in Ukraine. Without Satcoms, militaries face significant limitations in communicating over very long distances. While a few options exist, such as troposcatter, which can provide decent bandwidths at ranges up to 250 km by bouncing very high-power radio waves off the troposphere, these transmissions experience substantial signal power loss. This necessitates large and powerful transmitters and receivers. Additionally, troposcatter is generally unsuitable for inter-theater communication—for instance, from London to Afghanistan. Satcoms are therefore crucial for bridging this gap and will become increasingly so as initiatives like CJADC2 in the US, Collaborative Warfare in France, and Project ASGARD in the UK gain momentum. To learn more about this topic, Calibre Defence met with Helen Weedon, Managing Director of the Satcoms Innovation Group, an industry body that collaborates with companies in the satellite sector to promote innovation and efficiency.

GEO, LEO, and pLEO

Two orbits primarily dominate the Satcom space: Low Earth Orbit (LEO) and Geostationary Equatorial Orbit (GEO). LEO satellites are much closer to Earth than GEO, orbiting at altitudes typically between 160 km and 2,000 km. The International Space Station, for reference, orbits at approximately 400 km. LEO satellites travel very quickly, around 7.8 km per second, a speed essential to counteract Earth’s gravity. This speed and proximity offer several benefits, including lower latency, higher-resolution imagery, and rapid revisit times—a LEO satellite can orbit the Earth in about 90 minutes. However, they have a smaller “footprint” (the area of Earth they can see), requiring dozens or even thousands of them in constellations to provide continuous, workable solutions.

GEO satellites orbit much higher, at approximately 35,786 km. This altitude, combined with their position directly over the equator and zero inclination, means they appear stationary from Earth. While subtle gravitational influences from the Moon and Sun can cause them to trace a small, slow “figure-eight” pattern over a sidereal day, for practical purposes, they maintain a fixed position relative to the ground. This enables them to cover a very large area of the Earth beneath them.

Therefore, for GEO Satcoms to work from the ground, you typically only need an antenna that can be pointed at a fixed position in the sky. With LEO Satcoms, in contrast, it is necessary for the ground antenna to actively track the rapidly moving satellite, and the communication link will be seamlessly switched between different satellites as they pass through their orbit.

“This doesn’t mean that one is better than the other; they are different, and you want to be able to use them both for different things,” Helen Weedon from the Satcoms Innovation Group explained over a call in early July. “Sovereign geosynchronous constellations (like the UK’s Skynet or France’s Syracuse system, for example) are typically X-band, sanctioned by governments for government services. They undergo a rigorous process to ensure information security throughout the network and hardening against radiation and other nuclear events,” Helen added. This hardening means they are designed to resist a nuclear blast, and the communication links between the satellites and the ground are encrypted and hardened against jamming and interception. All of which adds significant cost, which is why GEO Satcoms have generally been the preserve of governments.

“Starlink is a commercial product meant for commercial use, which also means it can be turned off in certain areas,” Helen noted, before adding that “these pLEO (proliferated LEO) constellations become political because they are so big and do so much, yet they are not assured like sovereign capabilities.” Again, this does not mean that one is inherently better than the other, she emphasized. “There are times when you need the extra security of GEO, but there are other times where LEO makes more sense. It really depends on the situation.” One of the factors to consider is cost; using GEO satellites can incur considerable sums for a unit, even for relatively short exercises, while commercial LEO options might be significantly cheaper. Helen did sound a cautionary note on this: “You do need to train like you fight. So, if all of your training is on Starlink, and you finally deploy somewhere austere and you haven’t built the relationships and knowledge of your equipment to make it work, you will have to develop that knowledge and experience very quickly.”

The costs and relative resilience of LEO orbits to kinetic attacks are driving some defense interest for specific use cases, such as controlling drones over the Indo-Pacific. However, sovereign capabilities are making a comeback. The satellite industry, including many members of the Satcoms Innovation Group, meets for a conference every year. “This year, the big push seems to be towards having sovereign capabilities, which ensures that forces always have access to reach-back,” Helen said, summarizing her conversations at the 2025 Satellite Conference in Washington D.C. However, the major change from previous drives for sovereign capabilities is the significant growth of commercial companies within the space domain. “The commercial world has a lot of experience in operating satellite fleets and can form partnerships to provide sovereign capacity alongside the commercialization of orbital slots. GEO is limited in terms of orbital slots, so you could add a commercial Ku-band package alongside a sovereign X-band package to reduce or share costs,” Helen explained. There is some evidence of companies taking this approach with LEO; ICEYE, in particular, blends its commercial and defense offerings, and Helsing is planning a similar approach to its partnership with Loft Orbital.

The Satcoms Innovation Group and Flat Panels

Much of the focus on space technology often remains on the launches and satellites themselves. In fact, some sources suggest a disproportionate amount of investment is directed into launch operations, which represent a smaller fraction of the overall space economy. This is, of course, understandable, as there is no space industry without launch operations, but it does mean that the ground segment receives less attention. There have been recent developments in satellite antennas—specifically, the flat panel antenna—that are particularly useful for satcoms, and they are a key focus of the Satcoms Innovation Group.

“When it comes to Satcoms on the move, 5-10 years ago it was small parabolic antennas,” Helen explained. “There were a lot of ‘comms on the pause’ where they would stop and quickly set up a flyaway kit to get an update. You would set it up when you paused, but the problem was—what if you couldn’t pause?” A parabolic antenna is likely what comes to mind when you think of satellites: a large circular dish with a feed antenna at its center. The dish (or parabolic reflector) serves to focus all received energy at its center, where the feed antenna is. This is excellent for focused energy, but it means the user needs to know their own position and the satellite’s position in the sky, which is less of a problem with GEO because they are geostationary. For Satcoms on the move, the antenna needs to be able to receive signals at various angles (e.g., 20 degrees of elevation) to maintain visibility over the horizon, but it is primarily tracking the satellite in relation to the antenna’s movement. A LEO satellite, however, will move very quickly, which makes tracking them difficult, especially on the move. Flat panel antennas have the potential to change this; they are similar in some ways to the developments that have occurred in active electronically steered radars.

The flat panel is an array of antenna elements that are electronically steered to find and track satellite signals as they come to the Earth’s surface. There are, however, many limitations, and two key terms to consider are “skew” and “link budget.” “With flat panels, the further you move away from the vertical (the antenna’s boresight), the worse the signal gets; this phenomenon is termed ‘skew’,” Helen explained. “As you move away from 90 degrees (perpendicular to the panel), the skew gets worse and the performance drops off, sometimes quite rapidly. Knowing that drop-off is important for measuring antenna performance,” she added. This drop-off is one of the current driving points for the Satcoms Innovation Group, as there is a lack of comprehensive testing being undertaken for flat panel antennas. “If you have only tested it to 45 degrees, then you might find your routers are not connecting at 20 degrees,” for example, she said. “Digital twins are important, but the twin has to be based on physical testing. If you design the antenna in your design software and take what the software says it is going to be and put that into your digital twin, you don’t know if it will actually do that,” she added, referencing the current focus on digital twins as a means to reducing the requirements for physical testing.

Quadsat, a member of the Satcoms Innovation Group, provides antenna testing using drones. Importantly, it can use two drones to measure the ability of a flat panel to switch between two LEO satellites. Testing in this way can help ensure that the flat panel antenna meets the stated performance standards and delivers the required connectivity. “There are other ways to test, but they [Quadsat] make it more accessible by taking the test range to the antenna; the typical route is to take the antenna to a testing range and use a live satellite,” Helen went on to explain. This adds cost and time to programs that are already likely to be under significant pressure.

“Link budget” is the second term to bear in mind with flat panel antennas and Satcoms on the move. Helen summarized the term as follows: “A link budget accounts for all the gains and losses of a signal as it travels to and from space. Gain-over-noise-temperature (G/T) is the primary metric used to assess the received performance of an antenna and therefore its link budget. The ‘temperature’ refers to the system noise temperature; the electronic equipment creates noise, which diminishes the power of the satellite signal and generates heat in the process.” This is the reason that NASA’s deep space communications systems are cryogenically cooled, she continued. “You also need to know the grounding of the antenna, which is also important for reducing noise from surrounding metal components.”

So, why does this matter to the Satcoms Innovation Group? The body includes many members, including providers of satcoms and providers of satellite equipment, including antennas. Remember earlier in the article, how much of the investment is in the launch segment? This is indicative of the industry in general; some businesses deal with orbital assets, while others focus on the ground segment and may not provide both the antenna and satellites. If you consider your home broadband, the provider might be a large company like Vodafone, but the router will come from another company. Satcoms are similar. “If those numbers that the manufacturer gives to a satcoms provider are incorrect and they put them into their planning tool, then the user may end up being planned at a different quality than what is expected,” Helen explained. Using that home broadband analogy again, it would be similar to the router provider claiming it can handle 150 Mb/s when it can only handle 100 Mb/s. The testing offered by Quadsat is seen as one of the routes to helping address this and improving the ability of the Satcoms industry as a whole to meet its users’ needs.

Wrapping Up

“One thing we talk about a lot at the Satcoms Innovation Group is collaboration, and the whole point of the organization is to help the industry come together and discuss common problems and come up with solutions. And the more involvement we can have from the defense side, getting involved and contributing to those conversations, the more the commercial side can help them,” Helen concluded. There is increasing cooperation between defense and the commercial sector, especially in the space domain. This is in part because the commercial sector, led primarily by SpaceX, has reduced the costs of getting to space so significantly, which now means that states can establish sovereign capabilities for a fraction of the cost of previous launches. However, it seems that there is ample room for increased collaboration and innovation in the field of satcoms, with many potential opportunities and benefits to be realized.

By Sam Cranny-Evans, published on 7 August, 2025. The lead image is a US Marine Corps photo by Lance Cpl. Nathaniel Q. Hamilton. It shows Marines with 2nd Marine Division testing a Small Form Factor Satellite Communication (SATCOM) on the move (SOTM) device, while it’s attached to a Utility Task Vehicle (UTV).