CNN — 

Last fall, as Ukraine won back large swaths of territory in a series of counterattacks, it pounded Russian forces with American-made artillery and rockets. Guiding some of that artillery was a homemade targeting system that Ukraine developed on the battlefield. 

A piece of Ukrainian-made software has turned readily available tablet computers and smartphones into sophisticated targeting tools that are now used widely across the Ukrainian military. 

The result is a mobile app that feeds satellite and other intelligence imagery into a real-time targeting algorithm that helps units near the front direct fire onto specific targets. And because it’s an app, not a piece of hardware, it’s easy to quickly update and upgrade, and available to a wide range of personnel. 

US officials familiar with the tool say it has been highly effective at directing Ukrainian artillery fire onto Russian targets.

The targeting app is among dozens of examples of battlefield innovations that Ukraine has come up with over nearly a year of war, often finding cheap fixes to expensive problems. 

Small, plastic drones, buzzing quietly overhead, drop grenades and other ordnance on Russian troops. 3D prinoters now make spare parts so soldiers can repair heavy equipment in the field. Technicians have converted ordinary pickup trucks into mobile missile launchers. Engineers have figured out how to strap sophisticated US missiles onto older Soviet fighter jets such as the MiG-29, helping keep the Ukrainian air force flying after nine months of war. 

Ukraine has even developed its own anti-ship weapon, the Neptune, based off Soviet rocket designs that can target the Russian fleet from almost 200 miles away. 

This kind of Ukrainian ingenuity has impressed US officials, who have praised Kyiv’s ability to “MacGyver” solutions to its battlefield needs that fill in important tactical gaps left by the larger, more sophisticated Western weaponry.

Ukrainian servicemen of National Guard operate with a homemade anti-aircraft machine gun to destroy drones in Mykolaiv, Ukraine.

While US and other Western officials don’t always have perfect insight into exactly how Ukraine’s custom-made systems work – in large part because they are not on the ground – both officials and open-source analysts say Ukraine has become a veritable battle lab for cheap but effective solutions.

“Their innovation is just incredibly impressive,” said Seth Jones, director of the international security program at the Center for Strategic and International Studies.

‘Real world battle testing’

Meanwhile, the war in Ukraine has also offered the United States and its allies a rare opportunity to study how their own weapons systems perform under intense use – and what munitions both sides are using to score wins in this hotly fought modern war. US operations officers and other military officials have also tracked how successfully Russia has used cheap, expendable drones that explode on impact, provided by Iran, to decimate the Ukrainian power grid. 

Ukraine is “absolutely a weapons lab in every sense because none of this equipment has ever actually been used in a war between two industrially developed nations,” said one source familiar with Western intelligence. “This is real-world battle testing.”

For the US military, the war in Ukraine has been an incredible source of data on the utility of its own systems.