Challenger 3: Inside the TrueHunter Commander Sight with Thales

The Challenger 3 will become the heart of the British Army’s combat power for the next generation. At its core is a very lethal weapon system, realised through a potent mix of a new gun, and the thermal imaging TrueHunter Commander Sight from Thales.

As British soldiers deployed to Kuwait in 1990 ahead of Operation Desert Storm, they took with them the new Challenger 1, an evolution of the Chieftain main battle tank that had entered service in 1967. The tank had a mixed reputation, its lack-lustre performance in the 1987 Canadian Army Tank Shoot, had shed doubt on its ability to fight a war. But it did offer something that Chieftain did not – a thermal sight. The Thermal Observation and Gunnery System (TOGS) had been designed and integrated by a company that is now part of Thales from 1983. The L11A5 rifled main gun was known to be relatively effective with its APFSDS and HESH rounds out to 1,200 metres. 

Capt Tim Purbrick commanded a Troop of Challenger Main Battle Tanks during the 1991 Gulf War. On February 26th, 1991, his troop had moved to Objective ZINC and spent the morning watching an MLRS barrage fall on Iraqi positions. They knew there were several battalions of tanks ahead of them, most likely T-55s or T-62s. The day before, the British 1st Armoured Division had mauled Iraq’s 48th Infantry Division, capturing its commander, and the barrage that Capt Purbrick observed was likely elements of the largest British artillery bombardment since World War 2. His crew settled down for some rest, and the 2iC and his tank began digging scrapes for the troop’s tanks. Purbrick took up position in his turret and started scanning: 

“I took the first watch scanning the horizon, visually and thermally, flicking between the two systems. I used the commander’s grip switch, [a pistol grip used to rotate the turret], generally a 90 degree or wider arc in front of your tank. I had been scanning for 10 or 15 minutes…When suddenly, in the distance I started picking up hot spots on the thermal sight. What the hell were they? They were moving from north to south and then, it appeared, away to the east. At the range they were and with the degraded sight picture, I couldn’t tell what they were. But they were targets.”

Purbrick and his troops sprung into action, firing HESH and APFSDS rounds at the distant dots on their TOGS screens. That engagement had little success, the Iraqi vehicles were a long way away. But the next morning, they found more T-55s to their front, hidden behind sand berms. They set about engaging them, hitting a tank at 3,600 metres, and a fuel truck at 4,700 metres. The Challenger 1 gained some respect after the Gulf War, but its days were numbered, and it was replaced by the Challenger 2 from 1994. Challenger 2 carried on the TOGS legacy with TOGS 2, mounted in the barbette above the barrel. It was not independent, and tied to the rotation of the turret and elevation of the barrel. But still, thermal imaging was here to stay.

Seeing clearly: Challenger 3 and the TrueHunter sight

Tanks are all about the guns. Guns are the reason tanks exist, and getting those guns into the most dangerous places so that they can suppress enemy infantry, destroy their strongpoints, and fight back against armour is the reason for all of the armour. However, the L55 that will arm Challenger 3 entered service in 2001, it is hardly a new weapon. Yes, KNDS France with its mighty Ascalon 140 mm gun is positioned to change the field, introducing mammoth firepower that few platforms could survive. But, if the guns are the same, it is the sights that will set Challenger 3 apart. Calibre Defence met with Syd Gould, a former British Army tank commander who served on Chieftain, Challenger 1 and then Challenger 2, and now works for Thales. As well as Stewart Macpherson, Head of Digital Strategy for Thales UK to learn more about the Challenger 3’s new sighting system, and what it brings to tank warfare. 

“Moving from Chieftain, which was not stabilised and then Challengers that were and could fire on the move because of their optronics was fantastic. This next step is like moving from iPhone 7 to iPhone 13,” Syd explained, reflecting on his time in the British Army.  “The clarity of what you are seeing at a greater distance will help the crews fight at that longer distance. The improved ranges and the ability to see and fire further, will keep the crews safer at that point in time,” he explained. Think back to Challenger 1 engagement in 1991, “At the range they were and with the degraded sight picture, I couldn’t tell what they were. But they were targets.” Captain Purbrick had to reach back up his command chain, eventually reaching brigade level, to confirm that there were no friendly units to his front. 

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“It’s ok if everyone in front of you is the enemy, but the enemy could be anywhere now. If the vehicles are dictated as the enemy, then fine. But the clarity of the sight is really key, because it improves the time to engagement by enabling better target recognition,” Syd explained. The L30 rifled gun fitted to the Challenger 2 has proven its ability to engage targets at long range, but Challenger 3 and its L55 are designed to work together with the TrueHunter Commander Sight from Thales.

The aim is to increase the crew’s ability to engage targets at the outer limits of the range of the L55A1. For example, the DM63A1 armour-piercing fin-stabilised discarding sabot (APFSDS) round fired by the L55 has a maximum range of 4,000 metres, and the DM73 APFSDS that the L55A1 is able to fire can reach out to 5,000 metres. Other natures like the DM11 also have an effective range of 5,000 metres. You may already note that the Challenger 1 engaged targets at 4,700 metres, but again, the clarity is key – Purbrick was not sure what he was engaging, but knew he was looking at Iraqi vehicles. As Syd notes, battlefields are now more fragmented and the enemy could be anywhere, rather than straight ahead. This is why clarity is key. 

The Hunter-Killer

The Challenger 3 will be fitted with two sights, one for the commander and one for the gunner. The commander’s sight is the TrueHunter Commander Sight system from Thales; a variant of this is also fitted to the UK’s Ajax reconnaissance vehicles. “There are some subtle differences between the Challenger 3 and Ajax integration,” Stewart explained. “It means that the user has that familiarity but there are also economies of scale, shared pools of components that can be realised,” he added. But there are much bigger differences between the Challenger 3 and 2. Challenger 2 had a panoramic commander’s sight, but that sight did not include thermal imaging. Instead, the thermal sight was mounted in the barbette above the base of the barrel and shared between the commander and gunner. This meant that the crew could only scan one arc with the thermal imager, and that arc was also limited to the direction that the gun was pointing. This allowed for a limited hunter-killer capability, which is where the commander scans for targets with the panoramic sight, before passing them off to the gunner and loader to engage. However, they could only do this in daylight. 

“When I was a tank commander, we wanted to be able to see an independent thermal imager. The majority of the time we were deployed, we were using TI during the day and at night,” Syd told me. But he added that, “with this sighting system, anybody can initiate a hunter-killer engagement. If everybody is looking, including the driver, then they can initiate that process. The commander has to authorise it, but all of the sights can be used and fed into the central understanding.” The TrueHunter Commander Sight comes with the Thales SharpView series of thermal imagers, which also utilise new technology to improve their detection capabilities. 

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“The sensors themselves have moved to different technology from the original line scanning TI of Cr 2. One of the key differences is the use of MWIR for both commander and gunner, which gives improved atmospheric penetration. TI can sometimes struggle when there is a high water density,” Stewart explained. Line scanning was used by early thermal imagers and employs a single thermal detecting element within the sight, which would build the thermal image line-by-line. This increased the potential for distortion and lowered the resolution of the resultant image, it also used long-wave infrared (LWIR), which is much more sensitive to atmospheric changes and especially humidity – all of which could have been a factor when Captain Purbrick was finding targets at Objective ZINC. 

In addition, the Challenger 2 commander’s sight was air cooled and fitted with a compressor that required a lot of maintenance, Stewart recalled, he has worked on Thales sights for over a decade, including an upgrade to the Challenger 2 sight in 2019. The cooler for the TrueHunter Commander Sight is now integrated into the body of the imager, which helps with maintenance and improves resolution. 

But that’s not all, the TrueHunter Commander Sight is software-defined, including algorithms to help identify and track targets. “The detection algorithms essentially provide a full field of view target detection looking for hotspots and moving objects. There is also an upgrade path for DigitalCrew® with ML and AI,” Stewart added. DigitalCrew® is a suite of detection and tracking algorithms designed to alleviate operator burden. “Communication when things are busy is one of the fundamentals that you learn. You might have a Scottish driver, a Fijian loader, an Irish gunner, and an English commander. They all need to communicate using recognised orders. The training is there to be busy and challenge the crews, but if technology can help reduce the cognitive burden, then it frees up space in their mind to make decisions in a better way,” Syd suggested. 

“What I am interested in is the user community and Thales allowing that platform to complete missions in a different way. How might the crews use that capability and work as a team? There is a misconception that you need lots of vehicles, but if you have capabilities and can communicate effectively it means you can use the vehicles to the best advantage,” he closed by saying. 

The System Qualification Review for Challenger 3 is expected in 2026, which will finalise the build standard for the UK’s fleet of 140 tanks. It will be informed by trials that are currently underway, and delivery of the tanks is expected to be complete by 2030. 

Calibre comment: Clarity and lethality

The British Army is moving to a model that will see 40% of its combat power as “consumable” uncrewed systems, and another 40% as “reusable” uncrewed systems. The remaining 20% is to come from its crewed platforms. The move is essentially in response to what the British Government sees as an inexorable shift to drone-dominated warfare. So, the new capabilities of the Challenger 3’s TrueHunter sight will be incredibly important in this context as the 20% becomes vital to ensuring the remaining 80% can be deployed. Seeing further, but most importantly seeing more clearly, will help keep British armour out of reach of some of Russia’s ground-launched anti-tank missiles, and should give Challenger 3 crews the edge in tank-on-tank engagements. 

By Sam Cranny-Evans, published on 18th November, 2025. The lead image shows a Challenger 3 pre-production vehicle manoeuvring with its additional armour kit – or at least elements representing it – fitted. The TrueHunter sight is the green pedestal underneath the orange light on the turret roof. Credit: UK MoD Crown Copyright.