In the technologically escalating battle between drug smugglers and law enforcement, U.S. agents are looking to Israel's "underground Iron Dome" for a new tool to gain the upper hand.

Technological Arms Race

Drug smugglers have been very resourceful when it comes to the technologies they've developed and used to get their illegal product across the U.S. border.

From mobile car ramps that span up and across the border fence to ultra-light aircraft, to makeshift submarines -- even marijuana-firing cannons and catapults -- the technological arms race at the border has exploded with a certain type of innovation over the last few years.

But one tried-and-true, go-to tool for smugglers has always been tunnels, which with technological advancements have become quite sophisticated, hard to detect, and longer than ever.

Last week, a drug smuggling tunnel was discovered along the California-Mexico border that set the record for the longest cross-border tunnel ever discovered in Southern California. According to the Department of Justice's accounting, the tunnel was estimated to span 800 yards, and likely a lot longer due to its "zig-zagging" route, as Assistant U.S. Attorney Timothy Salel put it.

"It stretches from a house in Tijuana, Baja California, Mexico to an outdoor fenced-in commercial lot in an Otay Mesa industrial park, about 500 yards north of the international border," said Salel.

"It is equipped with rail and ventilation systems, lights and a sophisticated large elevator leading from the tunnel into a closet inside the Tijuana residence," he added. "It is one of the narrowest tunnels found to date, with a diameter of just three feet for most of the length of the passageway."

Finding Tunnels The Old Fashioned Way

Federal officials only found the tunnel after following suspects to the tunnel's hidden exit, underneath a dumpster.

"On the surface, few would ever suspect that traffickers were moving multi-ton quantities of cocaine and marijuana worth tens of millions of dollars in such an unassuming way, through this rabbit hole in the ground, in full view of the world around it," said U.S. Attorney Laura Duffy.

Most smuggling tunnels are only found through old techniques -- tips from informants or tailing suspects as they pick up an underground shipment at an exit point -- according to drug trade analyst Sylvia Longmire, who spoke with Fox News Latino.

But what if authorities could detect tunnels along the border from the surface?  

Underground Iron Dome

That's the hope that has the U.S. government earmarking $120 million over the next three years and partnering with Israel to help develop a new tunnel detector.

Current detection technology is mostly limited to finding dense or metal-laden objects close to the surface, like land mines, or discovering huge geological anomalies deep below, like natural gas deposits and sinkholes. More sensitive, sophisticated techniques are needed to find tunnels, which exist between those two extremes of size and depth.

The Israeli government, under threat from tunneling terrorists like Hamas, has been developing such a system for at least the past five years. Codenamed project "Hourglass," Israel has already invested the U.S. dollar equivalent of more than $60 million in the system, involving help from more than 100 technology, defense, and engineering companies.

First shrouded in secrecy, the tunnel detector hit public awareness after it was successfully used by Israel Defense Forces to uncover a very sophisticated concrete tunnel used by Hamas -- it was over twice as long as the record-breaking tunnel discovered in California last week.

Israeli media has been describing the technology as the underground equivalent of the country's Iron Dome anti-missile defense system. The Iron Dome, of course, was also an Israeli technological breakthrough that the U.S. decided to help fund and develop.

How Does It Work?

So far, we don't know exactly what the tunnel detecting system entails.

Publicly known details of the tunnel detection system have been, unsurprisingly, scarce. But according to the Financial Times' first report on the U.S. government's decision to get involved with funding and development, experts believe the system involves planting sensors in the ground and using algorithms to interpret the data.

Detecting tunnels under construction through vibration could be one aspect, but an easier task than finding them after they're already built.

For the latter situation, the system might even involve using controlled explosions to detect hidden geological anomalies, much like the way the oil industry uses to find new pockets of crude.

Never-Ending Escalation

Nevertheless, experts in smuggling expect that even if U.S. authorities successfully develop ways of detecting drug tunnels, the technological arms race will just escalate.

As Nelson Balido, CEO of the Border Commerce and Security Council, told Fox News Latino, there's already a new innovation in smuggling technology that authorities are on the lookout for: drones.

"As these tunnels become more prevalent and the systems to detect them gets better, drug traffickers are going to be using newer methods," said Balido. "The biggest problem for authorities when it comes to drones is that you can't detect them because they're so small."

Time to start developing a drone detector.