President Donald Trump has a vision of a "big, beautiful wall" made of concrete and steel on the US-Mexico border. In addition to that physical barrier, you could also see an armada of drones whizzing through the sky.

Many in the tech industry envision a drone-protected border as not just likely but inevitable, helping the US Border Patrol see farther and communicate better. Drones should make it easier for agents to distinguish immigrants and smugglers from the cows and coyotes that prowl along the border, advocates say.

"That could be the 21st century solution to the problem of protecting borders," said Chris Eheim, chief technology officer of Sunflower Labs, a home security drone startup, and a 15-year aerospace engineer. The US Customs and Border Protection agency already uses some massive military drones with 66-foot wingspans, but modern drone innovation could equip officers with smaller, cheaper aircraft that could be lofted from back of a truck.

Eheim's company isn't angling for border security business. But plenty of drone companies think their technology is a good fit. They include Tactical Micro, Fortem Technologies, AeroVironment, PrecisionHawk and Aria Insights.

Using drones at the international border would mark the latest expansion of these unmanned vehicles into our increasingly digital lives. Realtors use them to create spectacular promotional videos for properties, wedding photographers to take panoramic snaps of newlyweds, and pipeline operators to inspect their infrastructure. Amazon Chief Executive Jeff Bezos wants to deliver packages with the autonomous vehicles.

The drone option -- in addition to traditional concrete walls -- will likely get a closer look now that Trump is declaring a national emergency to obtain funding for border security measures. That move comes even as the president plans to sign a compromise bill that includes $1.38 billion for his marquee project. Congress passed the legislation Thursday to avert another government shutdown.

Already eyes in the sky for many law-enforcement agencies, drones are a likely prospect for border technology. Their cameras see farther than agents' eyes, and obstacle-avoidance sensors let them fly by themselves.

Customs and Border Protection didn't comment for this story. The White House didn't respond to a request for comment.

A 'smart wall'

Trump has demanded a 30-foot tall physical wall, made from steel or concrete and, in his view, harder to climb than Mount Everest. His unsuccessful attempt to fund the project led to the longest federal government shutdown in history, from December into January. Critics deride it as a "medieval" approach -- and scoff at the $5.7 billion Trump wants to pay for it.

Buying private property, digging trenches and erecting 30-foot-tall steel slats along even just some of the nearly 2,000 miles of the US-Mexico border is expensive and time-consuming. That's why high-tech drones are such an attractive alternative.

Rep. James Clyburn, a Democrat from South Carolina, supported the idea when he called for a "smart wall" in a January opinion piece in The Hill. Clyburn's virtual wall would use drones and sensors to create "a technological barrier too high to climb over, too wide to go around, and too deep to burrow under."

House Democrats offered a plan seeking, among other things, "cutting-edge technology along the border to improve situational awareness." The two sides worked on a $1.375 billion border security compromise to head off a government shutdown Friday. The package includes $100 million for drones and other surveillance technology.

"Drones are a natural fit for border security," said Diana Cooper, a senior vice president at PrecisionHawk, a company selling drone management tools. "It's much easier to retask a drone than a satellite."

But some activist groups aren't happy with the mass surveillance made possible by drones and other technology like facial recognition and biometric data including fingerprints for border security. One collection of groups, including Fight for the Future, Defending Rights and Dissent, Access Now, the American Arab Anti-Discrimination Committee, Free Press Action and Demand Progress, delivered thousands of signatures to House Democrats on Thursday from people opposed to the technology.

And in a letter to the House of Representatives last week, those and other groups said that Congress shouldn't expand funding for the border technology and that people far beyond should be concerned. "We know that the border is often a testing ground for surveillance technology that is later deployed throughout the United States. Ubiquitous surveillance technology poses a serious threat to human rights and constitutional liberties," the letter said.

Big drones, little drones

Drones -- also called unmanned aerial vehicles (UAVs) and unmanned aircraft systems (UASs) -- range from noisy quadcopters to massive payload-carrying mini-planes. Customs and Border Protection has used military-style Predator drones, which can fly as high as 9 miles, to look for illegal activity like smuggling near the border.

What's changing is that newer drones, smaller and cheaper than those big military alternatives, can be tailored for specific border uses. Among them:

Drone-equipped trucks. Tactical Micro already retrofits Border Patrol pickup trucks with a camera-equipped boom that reaches up 34 feet to give agents a six-mile view. So far, 14 are using the $340,000 systems. Now it's adding a drone that agents can send at the push of a button for closer inspections. "You can send a bird 100 feet above a target and tell what they're doing," CTO John Moulton said. "Is it mother and children? Drug smugglers with backpacks and rifles?"

Radar-aided drones. An agent can use Fortem Technologies' 1.5-pound tripod-mounted radar systems for a quick, long-range-scan during the day or night. An agent can then send a self-piloting drone to check out anything concerning the radar flags, said CEO Tim Bean. The systems should cost between $40,000 and $80,000 depending on whether it's used with small battery-powered drones or longer-range gas-powered models.

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Fixed-wing drones for longer flight duration. AeroVironment's drones can be lofted by hand and carried in a backpack. The company has already sold tens of thousands to the military, according to Steve Gitlin, the company's vice president of corporate strategy. A $200,000 Raven system comes with five aircraft, each weighing 5 pounds and able to fly 60 to 90 minutes.

Tethered drones for surveillance and communication. Aria Insights sells six-rotor drones that can hover 400 feet above the ground for long periods of time -- the record is 10 days -- because they're tethered to a ground station that supplies power. The drone can house two types of cameras or combine a single camera with a relay to expand radio communication range up to 40 miles, said Elizabeth Brozena, a vice president at the company. With a chain of drones tethered to trucks or buildings, "we can very quickly create a virtual wall," she said.

Drones wouldn't likely operate in isolation. Several executives saw their products as a good complement to walls, fences and other physical barriers.

And new sensor technology could help agents know where to dispatch drones. Fortem's radar sensors could be mounted to buildings. The same lidar scanners that are revolutionizing cars with 3D laser scanning could work on the border, too. Vibration-detecting geophones and buried fiber-optic cables can detect intruders.

High-tech troubles

Drones may be a boon for law enforcement, but some don't like how they can watch everything, all the time.

Constant surveillance in an area can mean privacy and civil liberties costs to residents and travelers in a border area, said Neema Singh Guliani, a lawyer for the American Civil Liberties Union who previously worked at the Department of Homeland Security.

"A lot of us would have objections to surveillance infrastructure in our communities that could track everywhere we went, every time we went to a doctor's office or a place of worship," she said. "It's capturing a large amount of personal data. And there's a history at the DHS of not putting in place the privacy protections that should be put in place."

Government scrutiny of existing border drones already raised concerns. A 2018 Government Accountability Office report found privacy problems with data handling, and a 2014 report found no evidence drones helped with goals like reducing border surveillance costs and apprehending people trying to cross the border illegally.

But tomorrow's drone technology is very different from the big Predators already guarding the country.

If you're on the border, you're likely to see more of them regardless of how today's political differences are settled, said PrecisionHawk's Cooper.

"Wall or no wall," she said, "the future is going to be reliant on drones."

First published at 5:00 a.m. PT.
Update 7:37 a.m. PT: Adds comment from activist groups opposed to border surveillance technology.
Update 8:25 a.m. PT: Notes that President Trump is officially declaring a national emergency.