With GPS-Guided Munitions, Ukraine’s Pilots Could Hit The Russians Almost 100-Percent Of The Time

The U.S. Defense Department reportedly plans to equip the Ukrainian air force with satellite-guided bombs.

The Pentagon’s proposal to give the Ukrainians Joint Direct Attack Munitions, or JDAMs, could result in the most important single upgrade for either the Ukrainian or Russian air force since Russia widened its war on Ukraine back in February.

That’s because the JDAM is accurate, whereas almost all the other munitions the Russian and Ukrainian air arms are hanging on their MiG and Sukhoi fighters and bombers … aren’t.

At present, a section of two Ukrainian Sukhoi Su-25 attack jets or Mikoyan MiG-29 fighters might expend a combined four unguided rockets or bombs for a chance at destroying a single target.

With JDAMs, the same two Su-25s or MiG-29s carrying two 500-pound JDAMs apiece feasibly could destroy four targets in a single sortie—and potentially at lower risk.

All that is to say, JDAM could change the air-power calculus as the Russia-Ukraine war grinds into its 10th month.

The JDAM plan, first reported by The Washington Post, isn’t a sure thing. It might still require the approval of U.S. president Joe Biden or his staff.

But if the transfer goes forward, it’s obvious what it would require: hardware and contract labor from U.S. defense firm Raytheon, bombs from U.S. military stocks and training for Ukraine’s fast-jet pilots.

It could happen quickly and without much fanfare. Consider how swiftly, and quietly, Washington this spring worked with Kyiv to modify the Ukrainian air force’s MiG-29s and Sukhoi Su-27 fighters to carry American-made, radar-destroying High-Speed Anti-Radiation Missiles.

JDAM isn’t really a bomb. It’s a guidance kit—one that fits on a variety of existing unguided munitions. The $25,000 kits, manufactured by Boeing, add a GPS seeker and steerable fins to 500-, 1,000- and 2,000-pound bombs.

It works something like this. A jet hauling JDAMs fly toward the battlefield. The pilot might already know the GPS coordinates of the enemy forces they want to strike. They also can receive updated coordinates mid-flight from spotters on the ground.

The pilot punches the target coordinates into a console that relays the data via a digital connection—a “MIL-STD-1760 interface”—that programs the bomb. They drop their bomb then fly away. The bomb picks up signals from GPS satellites, figures out where it is and where its target is, and navigates until it hits something solid.

As one of the first cheap and easy-to-integrate precision munitions, JDAM profoundly changed aerial warfare when it debuted in U.S. service in the late 1990s.

During World War II, an unguided bomb was likely to strike within 1,000 feet of its target. Thirty years later during the Vietnam War, the U.S. Air Force began using laser-guided bombs that usually struck within 400 feet of their aim-points. With JDAM, a bomb is likely to land 40 feet or less from its target—close enough to damage or destroy it, almost every time.

“What’s the significance of using JDAMs as we have seen in multiple conflicts?” U.S. Air Force brigadier general Pat Ryder, the Pentagon’s press secretary, said in October. “[It’s] the ability to conduct precision strike, to be able to strike a target that you want to strike when you want to strike it.”

That’s “a distinct advantage on the battlefield,” Ryder said.

Compare that to the Russian method of aerial bombing, which the Ukrainians largely have copied. Lacking reliable satellite navigation, guidance kits and advanced training, the Russian air force still mostly assigns its pilots to drop unguided bombs or fire unguided rockets at pre-surveyed map coordinates. Kremlin planners pick the coordinates based on whatever battlefield intelligence they’ve received.

That results in Russian pilots risking their lives and planes to drop lots of bombs on map grids where there may or may not be anything worth destroying. Worse, they do so inaccurately. So even if there happens to be a Ukrainian tank or some other target in the vicinity, it’s unlikely any single bomb is going to inflict any damage.

It’s not quite World War II, all over—but it’s close.

If the Ukrainian air force integrates JDAM, gets a steady supply of guidance kits and can connect crews and planners with good sources of intelligence on the ground, it can begin knocking out a Russian target with almost every bomb it drops.

The key to it all is the MIL-STD-1760 interface. The problem, for the Americans and their Ukrainian allies, is that the MIL-STD-1760 was meant for Western-style aircraft with digital avionics. Basically, the planes and JDAM already spoke the same language.

Perhaps anticipating a day when the United States might need to rearm old analogue aircraft with new digital weapons, Raytheon over the last decade or so has patented a variety of interfaces for translating between MIL-STD-1760 data and other signal formats. Electrical translators, basically.

To see these translators in action, check out the Philippine air force’s aerial campaign targeting Islamic terrorists back in 2012. Raytheon modified The Philippines’ Vietnam War-vintage OV-10 turboprop attack planes to carry JDAMs, which the OV-10 crews then used to blow up the terrorists’ jungle hideouts.

We’ve already seen evidence of similar interfaces in use in Ukraine. It wasn’t long after the Ukrainian air force first copped to firing HARM missiles at Russian air-defenses that a photo circulated online depicting a hastily-crafted missile pylon, bolted to a MiG’s wing, that must contain a new data interface.

A similar interface, probably also made and installed by Raytheon, should allow a Ukrainian pilot, sitting in their MiG-29, Su-25 or Su-27, to send target coordinates to their JDAMs.

Can the Americans spare the bombs? The U.S. Air Force, U.S. Navy and U.S. Marine Corps between them have bought hundreds of thousands of JDAMs. But they also have dropped many of them in various wars and training exercises since the late 1990s.

In fact, U.S. JDAM stocks, while classified, might be pretty low. The Air Force bought just 1,900 JDAMs in its 2022 budget—a 90-percent reduction compared to the 31,000 JDAMs it paid for as part of the 2019 budget. But the production rate should begin to increase. The Air Force wants 4,200 JDAMs for 2023.

As U.S. forces acquire new JDAMs, Biden through his legal “drawdown” authority could send older JDAMs to Ukraine. It’s this same drawdown authority that equipped the Ukrainian air force with older HARMs within just a couple months of the Russian invasion in February.

Ukrainian pilots, flying the roughly 100 fast jets the Ukrainian air force has left, might need a bit of training before they can begin tossing JDAMs at the Russians. Expect them to embrace the most creative tactics.

One advantage JDAM has over older precision-bomb types is that its seeker, which communicates with overhead satellites, has a wide field of view—especially compared to, say, a laser-guided bomb. An LGB peers down at the ground, looking for the reflection of a specially-encoded laser. Hills, trees and buildings can block that laser light and send the munition off course. GPS-guided munitions suffer no such constraints.

So a pilot doesn’t need to think too hard about the bomb’s needs. Instead, they can focus on aggressive flying that protects them from enemy air-defenses. Ukrainian pilots have taken to flying really, really low—treetop height, really—to mask them from Russian radars.

With a load of 500-pound JDAMs underwing, a Ukrainian MiG pilot can stick to their low-flying habit. As they near the target zone, they can pitch up, release a bomb and send it arcing toward the enemy before they pull a hard turn, pop decoy flares and dive back toward the ground to escape enemy missiles.

The JDAM, hurtling in the general direction of the target, can find its GPS signal all on its own—and home in.