Some precision-guided weapons supplied by the United States to Ukraine have proven ineffective on the battlefield, their accuracy severely degraded by Russian jamming, according to Ukrainian commanders and Ukrainian military research projects.
Two classified Ukrainian reports found that the shells performed well when first used in combat but began to lose effectiveness as Russian forces adjusted their defenses, a problem that two artillery commanders said prompted the Ukrainian military to stop using the weapons.
This report was published by Washington postThe New York Times reported that the report, which focuses on the U.S.-made Excalibur, a 155-millimeter guided artillery shell, and the Ground-Launched Small Diameter Bomb, or GLSDB, was shown one of the reports by people familiar with the research. The second report describes it but has not been shown to reporters. The people requested anonymity because the reports contain classified military information.
Every war is a laboratory for weapons systems, and Ukraine has provided a testing ground for weapons that have never before been used against an advanced, high-tech foe like Russia. The performance of American and Russian weapons, both defensive and offensive, is closely monitored by the Pentagon and NATO, as well as Russia and China, with important implications for future weaponry.
More immediately, Ukrainian commanders say some of the weapons provided to them by the West have failed and are causing casualties.
Russia has deployed electronic warfare systems around static targets such as headquarters and command centers that could be targeted by Ukrainian precision weapons. The jamming signals from these systems were so numerous that they overwhelmed the GPS signals that guided Excalibur’s targeting software, said Thomas Withington, an electronic warfare expert and associate fellow at the Royal United Services Institute in London.
The data in the report confirms comments made in recent months by Ukrainian military officials, including former Army Chief of Staff Gen. Valery Zaluzhny, who said some Western projectiles gave Ukraine a clear advantage in its battles with Russian forces, but only for a short period of time.
General Zaluzhny called the Excalibur shell an example of a Western weapon that failed because its targeting system used GPS, or the Global Positioning System, which is particularly vulnerable to Russian jamming.
Ukrainian officials and military analysts say similar problems exist with artillery shells used by the Joint Direct Attack Munition (JDAM) and the High Mobility Artillery Rocket System (HIMARS), both of which rely on GPS.
The second military report said the GLSDB, a precision-guided munition produced jointly by Boeing and Sweden’s Saab, has a longer range than Excalibur and is also hampered by Russian electronic warfare.
Andrew Zagorodniuk, director of the Center for National Defense Strategy, a Kyiv research institute, said the Ukrainian army has stopped deploying GLSDBs on the battlefield.
An official from the Department of Defense’s Office of Press Operations, who spoke on condition of anonymity in accordance with military protocol, said in an email that the United States has provided Ukraine with more than 7,000 155mm precision-guided artillery shells since February 2022, but added that he could not provide more specific information.
“We are acutely aware of the electronic warfare threat posed by Russia to Ukraine, and that it continues to evolve,” the official wrote.
“As a result, we work closely with Ukraine and our defense industry partners to continually assess these threats and quickly provide solutions to help ensure Ukraine remains effective in a very complex EW environment. This includes the ability to deliver precision munitions on the battlefield,” the official wrote, using the word EW to refer to electronic warfare.
People familiar with the project said Ukraine started the study because of the severity of the targeting failures, but also out of a spirit of cooperation as NATO allies. One of the people said it was important for the Ukrainian military to give feedback to Western partners on how its weapons perform against advanced military powers such as Russia.
The researchers collected data on the use of nearly 3,000 Excalibur shells fired from U.S.-supplied M777 howitzers on the Bakhmut front in Kherson in the south, Kharkiv in the northeast, and the Donetsk region in the east from December 2022 to August 2023.
Report shows that the proportion of confirmed successful attacks has been declining over time From January to August 2023, the success rate dropped from a high of 55% to 7% in July and 6% in August, the months when Ukraine’s difficult summer counteroffensive reached its peak. At one point, only one of 19 Excalibur shells hit its target, according to a person familiar with the matter. At that rate, the report calculated, the cost of a successful attack would soar from $300,000 last January to $1.9 million in August 2023.
The commander of the Ukrainian artillery forces confirmed that when the “Excalibur” shells were first put into use in 2022, they had very high accuracy in shooting targets, but were later effectively offset by Russian interference.
“We have some problems with accuracy,” said a commander of the 45th Brigade artillery unit operating in the Donetsk region, whose call sign is “Musician” in line with Ukrainian military protocol.
The U.S. M777 howitzers used by Music’s team were praised for their capabilities when they were first introduced to the Ukrainian theater of operations in 2022. But Music said his unit stopped using the Excalibur shells in early 2023 because of their low effectiveness.
Instead, he said, they fired unguided artillery shells, which are less accurate and require large amounts of ammunition to hit their targets.
Another commander, Oleh, who gave only his first name for security reasons, said he sometimes received supplies of other weapons, including laser-guided munitions, that were less affected by Russian GPS jamming.
In the heat of war, it is not uncommon for weapon systems to lose effectiveness as determined adversaries always find new ways to counter them.
Military analysts say the most effective countermeasure to GPS signal jamming is to eliminate the source of the jamming. Withington said Ukrainian forces are focusing on destroying Russian fixed radars and other jamming equipment, especially in Crimea, so they can strike targets such as command posts and supply depots behind enemy lines.
At close range, both Russian and Ukrainian forces use mobile electronic jammers to deflect explosive drones, which use GPS to track their targets.
But Michael Bonnet, a RAND Corp. engineer and U.S. Navy electronic warfare expert, said Russian jamming is not indestructible. Countermeasures can include simple techniques, such as changing when and where munitions are fired. Guidance systems that rely on lasers or terrain maps can avoid the problem of GPS jamming. Western suppliers have also developed software patches for some projectiles to improve resistance.
“You always find a way to achieve your goals,” Mr. Bonnet said.
He noted that the Excalibur was designed in the 1990s, when GPS was in its infancy and electronic warfare technology was far less advanced than it is today. “Those old ones were fundamentally problematic,” he said. “They should have been equipped with better weapons sooner.”
Daniel Pate, a senior fellow at the Hudson Institute, a Washington research group, warned that Excalibur’s experience in Ukraine was an example of how advanced weapons systems could be hampered by a lack of software adaptability, and he urged the Department of Defense to foster a culture of innovation and agility that can adapt quickly.
“The Ukrainian radio has a life cycle of only about three months before it needs to be reprogrammed or replaced as the Russians optimize their electronic warfare against it,” Pat wrote in his testimony. “The new weapon system is only at peak effectiveness for about two weeks before countermeasures are deployed.”
