From AI to Starlink: How drone tech is reshaping war in Ukraine

As the war in Ukraine drags into its fifth year, drones have come to completely dominate the front line -- a transformation in modern warfare that is being watched around the world.

Here is a look at the technology that is reshaping the war, four years after Russia launched its full-scale invasion by pouring tanks and men over the border:

- Kill zone -

Ranging from cheap commercial devices designed for civilian use to explosive-packed miniature aircraft, drones are responsible for up to 80 percent of battlefield damage, Ukraine's Defence Minister Mykhailo Fedorov has said.

"Modern warfare is now impossible without drones," Koleso, a Ukrainian infantry soldier, told AFP in eastern Ukraine.

The front line has been transformed into a "kill zone" stretching up to 20 kilometres (12 miles) deep -- "an area between two sides where nothing can survive because it's constantly monitored by drones", military expert Kateryna Bondar explained.

Soldiers can only operate there in small groups, moving fast and with their eyes fixed to the sky, hoping to stay undetected.

Heavy pieces of artillery, as well as sluggish tanks and armoured vehicles, are too slow and visible -- making them easy targets for both sides.

Unwilling to send more men that necessary into the kill zone, Ukrainian troops use ground drones to ferry supplies to dangerous areas and to evacuate wounded soldiers.

- Fibre optics -

Maintaining a stable connection between the drone and its operator, controlling it remotely, is a crucial task.

"That's where the real race is happening -- communications and connections," Bondar said.

Initially, most drones operated on a radio connection.

But they proved vulnerable to electronic warfare -- the practice of jamming and intercepting enemy craft, causing them to drop out of the sky or lose connection to the operator.

Russia has turned to drones controlled by ultra-thin fibre-optic cables, largely immune to electronic jamming.

In scenes that resemble a dystopian sci-fi movie, their widespread use has left swathes of frontline cities and fields entombed in webs of cable.

- Starlink -

In another alternative to radio control, Ukrainians have begun attaching Starlink terminals to drones.

This allows them to fly using a satellite internet connection.

"We need to fly far away with a stable video signal and stable control," said Phoenix, a commander from Ukraine's Lasar Group, a pioneer in the use of Starlink.

Russian troops soon started copying, until Ukraine pushed Elon Musk last month to disable unauthorised Russian terminals.

The move disrupted both Russian and Ukrainian systems, military observers said.

The US-based Institute for the Study of War said the switch-off likely helped enable a localised, but rapid, Ukrainian advance in the southern Zaporizhzhia region in early February.

- Air defences -

The spread of drones has forced a revamp of air defence systems.

Firing advanced missiles -- which can cost millions -- to down drones worth just a fraction of that is too expensive a response.

Alongside jamming, Ukraine has also developed cheap interceptor drones built specially to destroy other craft mid-air.

"We opened the chapter of the war of drones with drones," said Marko Kushnir of General Cherry, a leading interceptor drone maker.

Roads near the front have been equipped with protective nets attempting to stop attacking drones, while trucks fitted with anti-drone cages and drone jammers speed along them.

Machine guns are also a last resort to shoot down drones from the sky.

Ukraine's Western allies have increasingly looked to Kyiv's experience after Russian drones made repeat incursions into European airspace in recent months.

- AI -

Engineers are racing to equip drones with artificial intelligence to improve their performance.

Ukrainian firms such as The Fourth Law (TFL) say they have developed so-called terminal guidance, which allows AI to take control of a device in the final moments before impact.

This is meant to improve the accuracy of strikes, especially as connection is typically lost in the final moments before a hit.

"Russia and China are also developing such technologies, and if our countries don't... we will lose," said TFL's Maksym Savanevskyi.

But full autonomy remains some way off.

"AI is performing a helping function rather than substituting human," said Bondar, the military expert.

"I thought they could simply remove people from battle equipment, that it could be fully automated. That's a naive view," said former Google CEO Eric Schmidt, now head of SwiftBeat, a company that supplies AI drones to Ukraine's army.

"For the foreseeable future, you'll have drones first, people second," he told a conference in Kyiv.

All the way on the eastern front, Koleso said foot soldiers would always remain relevant.

"Until you plant the flag yourself, with your own hands, and take the position, it cannot be considered yours," he said.