When the United States’ military stealth tech bomber was rumored and then when it made a public debut, it was the first-time advanced stealth technology was a reality instead of something out of a science fiction novel.
Even as the US was working on the tech to hide the profile of the bomber, work was underway on how to detect it. Since unmanned aerial vehicles (UAVs) are now an internal part of the world’s major militaries, stealth tech is integral to these aircraft. Again, the US is leading the pack, but China, France and Great Britain are also making major strides with China closing the gap rapidly.
Where concealment is concerned with military matters the top things that must be hidden are:
Staying as quiet as possible is critical as next generation long-wave infrared search-and-track sensors worries some analysts about the engine and propeller noise. Anyone who’s ever heard a small civilian drone knows the buzz. Helicopter pilots say they do not fly but beat the air into submission and create a lot of noise at the same time. Prop and jet-driven UAVs are sound machines.
The private sector is making strides in killing propellor noise. While the Rowe brothers creation, a shroud around the prop, is designed for drones in the movie industry, the sound-killing tech can easily translate across to UAV applications with a few tweaks. Another company has tweaked the propeller blade to get a noise reduction.
Silencing the jets on UAV may also take a page from the civilian world. Georgia Tech and Lockheed Martin are tackling the jet noise issue on several fronts. NASA is investing heavily into a new generation of supersonic passenger planes that promise “60 to 65 decibels per boom (at least as heard from the ground).” A normal conversation is 60-70 decibels at 3-5 feet.
Combustion is hot. Electrical motors cut way back on the heat produced, but batteries add weight which reduces flight time. One solution being explored by some is a combination UAV. It runs off a fueled engine until it closes in on a target, then switches to battery operation. This cuts the heat signature and the noise when noise-reduction measures are also included. Mission accomplished, it eases away and restarts the engine to either recharge the batteries for another run or the ride home.
It may appear that sacrificing stealth to move is a trade-off that must happen. Not precisely. A UAV must fly, but it the body of the UAV does not have to change shape. In a conventional aircraft, ailerons move. These dictate how a plane turns, climbs and descends by changing the shape of the wind foil (wing or rudder). The blades on a stealth helicopter are often a giveaway.
A new military stealth tech drone from BAE Systems in MAGMA in-flight trials has no moving external parts. As Popular Mechanics reports, ‘Control surfaces can also affect an airplane’s carefully shaped stealth profile, as the fin-like device moves upward or downward, momentarily making the aircraft slightly more visible to radar.”
A slight advantage is all that’s needed to get a lock and take measures against the incoming craft.
Hiding by color is the oldest form of stealth around; think stripes on a tiger. Mirrors that reflect the surroundings are great for hiding, depending on the surroundings. But cloaking tech vis a vi Harry Potter invisibility cloak or a Klingon cloaking technology may not be as silly as it sounds. It is a step closer to reality. This kind of tech has the possibility of blocking everything but sound; muffling technology will take care of that.
Hiding transmission signals is very difficult to do. Radio waves, even a tight beam, are going to spread. Using code, rapid frequency jumping and burst communications are ways around eavesdropping. Laser communication is the best we can do right now to avoid detection. Since lasers spread very little, intercepting means being in the direct line of transmission, which then becomes easy to detect because of signal degradation or transmission delays.
The arms race does not have a finish line. As soon as a new advancement comes online, someone is hard at work trying to defeat it. The South China Morning Post says the military there has a “T-ray,” terahertz radiation, radar that penetrates anti-detection coatings on manned and UAVs. This is not new tech, but a modification of existing technology. T-rays are used in industrial applications to spot defects in layered metals.
As Defence Aviation says, the key to defeating the military stealth tech may be as simple as incorporating a whole suite of detection systems into one array. While a UAV may beat one, two or three of the detection methods, that means it must compromise on something else. “The U.S. Navy and Lockheed are already working in these areas of stealth technology thereby creating the need to develop even more sophisticated sensors that cue radars about the invisible blackbirds that roam our skies,” the website says.
Retired USAF officers Maj. Gen. Mark Barrett and Col. Mace Carpenter sought to answer in a report, “Survivability in the Digital Age: The Imperative for Stealth,” produced by the Mitchell Institute for Aerospace Studies. “Over the long run, the U.S. will engage opponents who field increasing numbers of powerful digital multi-band radars,” the authors wrote.
To see what tomorrow can bring, look to science fiction. What was pure speculation 50 years ago is now held in your hand, so you can watch funny cat videos downloaded from a server on the other side of the planet.
The race for better military stealth tech can be in two camps. Cloaking technologies which are already underway and anti-gravity. Conspiracy theory websites are full of stories of government work on anti-gravy devices but have little in the way of concrete proof of the claims.
So is anti-gravity going to be a thing? No one knows. But it is being researched. Get past the “how could it work” to “what could it do” and the implications are stunning. We already know gravity can bend light so using the tech to thwart detection systems should be even simpler. However, making anti-gravity happen is many years off, if ever. Newer military stealth tech aircraft are on the horizon in the USAF B-21 and the Navy’s X-47B UAV.
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In regards to long range commercial drone control, according to wireless technology company Qualcomm, “5G connectivity will enable a worldwide boom in drone use, for fun, research, and business.” But for now, U.S. drone activity is limited to line-of-sight control. Regulations will need to catch up to the fast-developing technology.to enable the future of long range commercial drone control.
“A Highway in the Sky”
Research on the control of drones parallels work being done on autonomous vehicle technology. Dr. Harita Joshi of the University of Warwick spoke to Telecom TV about the development of ultra-reliable and low latency 5G networks that would allow for accurate communication with self-driving cars. Others are talking about “self-flying aircraft”.
China Mobile used the term “flying automotive” when referring to the 5G drone network they were testing with Ericsson in 2016. Achieving end-to-end latency of 15 milliseconds, their 5G drone was able to make handovers between towers shared with normal cell phone users.
Commercial long range drone control is in deep development. Take Alphabet (aka Google) who's been working on ways to deliver mobile connectivity from the air. In 2014 they bought Titan Aerospace and turned it into Project Skybender. The aim was to launch a fleet of lightweight, solar-powered drones that would fly in the upper atmosphere for up to 90 days at a time. Alphabet abandoned Skybender in 2016, preferring to concentrate on the use of balloons through their Project Loon. Another venture in long range drone control is Qualcomm, who want their unmanned aerial system (UAS) to be autonomous through development of UAS Traffic Management (UTM) controls.
Director of Marketing Maged Zaki blogged about the “Path to 5G: Building a highway in the sky for autonomous drones”. “When UTM systems are deployed, we envision fleets of drones flying missions autonomously while connected to operators and regulators.”
No one wants to worry about drones falling from the sky. The FAA in the U.S. has restricted drone usage to Visual Line of Sight (VLOS). However, in 2016 the FAA granted an Extended Visual Line of Sight (EVLOS) operations waiver to commercial drone company Precision Hawk.
But for Beyond Visual Line of Sight (BVLOS) control of drones, operators need something more for long range commercial drone control. “Many of the anticipated benefits of drones, including delivery, inspections and search-and-rescue will require a highly secure and reliable connection,” said Qualcomm’s Chris Penrose, senior vice president, IoT Solutions, AT&T, according to a press release.
Dr. Joshi underscored in her interview the problem of latency and the need to service vehicles traveling at high speeds. The ITU published “IMT Vision”, a paper about 5G, in which they addressed these issues: IMT-2020 would be able to provide 1 ms over-the-air latency, capable of supporting services with very low latency requirements. IMT-2020 is also expected to enable high mobility up to 500 km/h with acceptable QoS.
To achieve the goals of long range commercial drone control, researchers are experimenting with a range of bandwidth called millimeter-wave radio. The new band spans from 30 to 300 gigahertz. Way back in 1895 the polymath Jagadish Chandra Bose was experimenting in this spectrum. An August 2014 article in IEEE Spectrum tells the story: The intrepid scientist “sent a 60-GHz signal through three walls and the body of the region’s lieutenant governor to a funnel-shaped horn antenna and detector 23 meters away. As proof of its journey, the message triggered a simple contraption that rang a bell, fired a gun, and exploded a small mine.”
Despite the early research, attempts at harnessing millimeter-wave frequencies turned out to be extremely expensive and infeasible. The spectrum propagated poorly between towers and was scattered by rain. “The huge advantage of millimeter wave is access to new spectrum because the existing cellphone spectrum is overcrowded,” says Jacques Rudell of the University of Washington. The Guardian writer Mark Harris wrote about it when he broke the story “Project Skybender: Google's secretive 5G internet drone tests revealed” in 2016. Despite Skybender’s demise, plans to harness millimeter-wave technology continue.
Hobbyists have taken to drones as a new tech toy, but other use cases will contribute to the drone boom. Companies like Alphabet hope to deliver internet to remote and under-served areas. Drones are useful in disaster recovery, search-and-rescue, and hazardous material situations. Amazon has already done long-range test deliveries. Pizza delivery by drone is not far away. And drone racing – like the 2016 World Drone Racing Championships in Hawaii – is a growing sport.
AT&T Foundry offered “10 Bold Projections on the Future of Drones”. These include swarming technology, onboard analytics, IoT support, AI and robotics, and the use of drones for dynamic communications networks. Whatever commercial applications await drone technology, it’s clear that they will be dependent on secure, fast, and reliable communications. 5G technology will likely play a significant role in the evolution of long range drone control.
NextGen has worked with startups, defense contractors, and aerospace companies who build commercial drones for package delivery, police surveillance, and counter-intelligence needs. Our team of executive search recruiters have expertise in both aerospace UAVs, drones, stealth tech sensors, as well as wireless connectivity.