SpectraLoc: Inside the Danish ELINT capability that helps Ukraine

Danish company Quadsat moved from commercial satcom to defence and now its SpectraLoc ELINT capability is being used in Ukraine to find high value targets. This type of capability is crucial to ensuring that armed forces can find targets without giving their own location away. 

BLUF:

• Quadsat has moved from the commercial satcom world more fully into defence. Its Spectroloc system is now being used in Ukraine to support Ukrainian Armed Forces. 
• Passive detection in this way helps Ukraine to preserve life and counter some of Russia’s strengths. 
• It is a type of capability that would also be very valuable to NATO forces in Europe as it would help to degrade Russia’s layered air defences. 

When Russian forces invaded Ukraine again in February 2022, a few things about their concepts of operations were well-known. We knew that air defence would play an important role, and that counter-battery fires were key. Air defence because Russia would want to deter any outside information, keeping a local war local, rather than allowing it to escalate. And it would also be central to countering Ukraine’s own airpower, especially its drones like the Bayraktar TB2. Counter-battery is a core role for Russia’s artillery officers, who are charged with ensuring that their forces have firepower superiority. This means flattening enemy positions ahead of an advance and making sure their artillery cannot contribute to the fight.  

In both cases radars were expected to play a defining role. Russia employs dozens of air defence radars in different configurations. In accordance with their doctrine, they could be expected to defend critical nodes but limit the time that their radars are switched on, which makes finding them more difficult. The counter-battery fight was initially supported by a range of large Russian radars from the Zoopark family, as well as many smaller radars that are man portable. Russian counter-battery fire and air defences are effective, they limit Ukraine’s ability to amass firepower in any given area, and force its forces to fly more restricted routes. This means that finding and engaging those radars is and always has been a priority within Ukraine’s targeting process. 

So, in mid-November, 2025, Calibre Defence spoke with Klaus Aude, from the Danish company Quadsat. To some of you, this may sound like a surprising choice to learn more about targeting radars. Quadsat’s founders set out in 2017 to improve the testing and calibration of satellite communications antennas. By taking their laboratory to the radar, rather than the other way round, they could check that the satellites and ground components were functioning properly at lower cost than before. This business model went well, but in 2022 the company turned its attention to defence and developed the SpectraLoc capability with its own funds. The system is a passive electronic intelligence (ELINT) detector weighing less than 3 kg, which means it can be carried by a few different types of drone. ELINT is intelligence gathered by passively intercepting and analysing non-communications electromagnetic radiations (like radar and telemetry) emitted by foreign systems to determine their capabilities, operational patterns, and location. Doing it passively simply means that the detector is not emitting anything, it is sort of like a smoke alarm in that sense. 

“We took what was used for orbital systems and transferred it into electronic warfare (EW), it was a huge success and it was quite clear that we had something that was quite unique. At an altitude of 1,500 metres, they can detect targets out to a few hundred km plus,” Klaus explained over a call. Drone-carried EW is an important part of modern capabilities, it enables a force to detect and intercept signals over a battlefield without necessarily risking a large expensive aircraft like an RC-135 Rivet Joint or PEGASUS. There are also land-based systems that can be used for detecting radio frequency signals, some developed in Ukraine and many developed outside of it. The challenge for land-based systems is that terrain and clutter can interfere with RF signals, reducing the detection range. Placing the detector on a drone enables it to capture many more signals from a much greater range as the ground cannot get in the way of radar emissions. 

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“We cover 2 – 31 GHz with our satcom tech, but EW is 2-18GHz, most defence equipment is located within this area so that is where SpectraLoc is focused. But we can also narrow it down to a few GHz, you just need to pre-set it before deployment. In one customer trial recently they said “how the hell can you do this, it’s not natural?” And we said no, it’s not,” Klaus smiled as he told me. 

Using a single drone and SpectraLoc combination, it is possible to identify and geolocate a target. “We use angle of arrival for geolocation, it pinpoints a target multiple times, and when we have done that, we have a very strong indication of where the target is with a single drone. If you have multiple systems, then it goes much quicker and will be more accurate,” Klaus explained. Angle of arrival essentially means that the receiver on the drone measures the angle or bearing of the signal when it is received, which might be something like 45° northwest. Using an array of antennas, it is possible to measure the subtle differences between phases of the signal, as it must travel slightly different distances to reach each part of the antenna. 

Ideally, the drone would collect more than one bearing to triangulate the signals and provide a more accurate location for the target. “The unique element of the system is that each threat has its own fingerprint, and the operator can look in a specific frequency band and the waterfall to see how it emits. Together that gives a fingerprint of the station that is being detected. If it is detected one and then again a bit later, the operator can indicate that it is one system that has moved,” Klaus said. He added that so far they have worked with multiple companies on this project, including Skyeton, which recently established a presence in the UK, likely reflecting its interest in the UK’s Project CORVUS. 

The video above shows the final stages of an engagement against a Russian Kasta-2E radar. It is not known how the radar was found, but it would be possible for something like SpectraLoc to provide an initial cue of the target location that is then confirmed through visual reconnaissance.

Quadsat’s move into defence through SpectraLoc has been quite successful. “Before 2022, the business was 90% satcom, 10% defence, but that has shifted and it’s basically the reverse,” Klaus said. Adding that the latest funding round included Join Capital, which is entirely focused on defence. SpectraLoc also has applicability in law enforcement; according to Klaus, drug cartels in South America are increasingly using radars to alert them to the launch of police helicopters and aircraft. “Just put a quadcopter up to 500 m or more, and you basically have a range that is good enough in these scenarios. SpectraLoc could also be fitted to tethered solutions, high masts, aerostats and that sort of thing,” he explained.  

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As a result of the company’s success and growing reputation, “there is considerable interest in Quadsat, and we are looking at a range of interesting partnerships. It’s rare to be in this position as an SME, and it’s an opportunity for us to push our technology into the market in a much stronger way.” Klaus concluded by saying that there was a lot of interest from some of the major EW houses, “in many cases we complement the big EW companies. We do also compete in some situations, the larger EW houses try to rule in the business, but as an SME we try to hold on and focus on what we are good at, and it pays off.”

Calibre comment: Find, fix, strike 

The UK and others are fixated on the recce-strike process. Put simply, find a target, fix it in place, and strike it from a long way away in the shortest time possible. This is all well and good providing that the “find” element actually works. This requires complementary systems in space, in the air, and on the ground. However, relatively modest procurements of drones mean that a large force will likely struggle to resource all of its fires capacity with targets from that means alone. Additionally, finding air defence radars is, or should be, a higher priority for NATO forces. Doing this passively, and ideally from close to friendly airspace without risking big wing ISR platforms is a smart move, and would go a long way to improving the ability of countries like the UK to counter Russia’s air defence assets. 

By Sam Cranny-Evans, published on January 20, 2026. The lead image shows a HIMARS in service with Ukraine firing a guided missile at a target. Credit: Ukrainian MoD.