The skies are crowded.
There are more aircraft and more types of aircraft flying in the National Airspace System in the U.S. than ever before. There has been an astronomical rise in the number of drones alone; civilian-owned unmanned aircraft systems registered with the Federal Aviation Administration reached more than 1.5 million in 2020. That included more than 1.1 million for recreational use.
That could create enough congestion to cause safety problems and flight delays if it were left unchecked. A number of technologies, including some from Raytheon Intelligence & Space, a Raytheon Technologies business, could help mitigate these problems.
"We're seeing a lot more aircraft and a wider variety — some big, some small, some that go fast, some that don't — and these present a challenge for air traffic controllers because they all want to fly to the same places," said Kip Spurio, Raytheon Technologies managing director of air traffic systems. "We need new technology for a more complicated sky."
Reach for the STARS
Raytheon Technologies' Standard Terminal Automation Modernization and Replacement System, or STARS, is used by air traffic controllers at airports and Terminal Radar Approach Control facilities to monitor and direct air traffic up to 60 miles around airports and up to 14,000 feet in the air.
The STARS program receives radar data and flight plan information and presents them to air traffic controllers so they can monitor, control and accept hand-off of air traffic. Through 68 airports and other sites, including many of the world’s busiest airports, STARS handles approximately 80 percent of the air traffic in the U.S.
"STARS is a replacing all of the FAA's old analog, single color, round displays," said Spurio. "It's like buying a new iPhone; you need to add all the latest and greatest apps to really take advantage of its processing power. STARS will allow the FAA to add apps and enhancement packages down the road."
Low power, high performance
Raytheon Technologies' Skyler is a one-meter-square, low-power, Active Electronically Scanned Array, or AESA, software-defined radar. While originally designed to be networked to provide high-definition weather monitoring at all altitudes, Skyler can be adapted for different applications.
"Besides weather, we have customers interested in networking these on cell towers and buildings every 20 miles or so to monitor small drone traffic," Spurio said. "It also has no moving parts, so Skyler is more reliable and easier to maintain, which gives it a longer lifetime and less upkeep costs."
The FAA projects that there could be four million drones in the hands of hobbyists and commercial users by 2021. Whether flying in the cockpit or with the joystick, all pilots must "see and avoid" other aircraft and obstacles. That can be difficult with a drone; you can quickly lose sight of a small quadcopter once it reaches higher altitudes or when it's obscured by obstacles like trees or buildings.
The U.S. Air Force found the FAA's "see and avoid" restriction especially challenging because they needed to fly their unmanned aircraft systems, like the Global Hawk and Predator, from U.S. bases to nearby ranges, which meant crossing 20 to 30 miles of civilian airspace.
"The Air Force used to have to resort to ground spotters every couple of miles or so, as well as having chase planes follow the drone, which wasn't very practical," Spurio said. "Then we modified STARS so that it could use radar data to alert Air Force drone pilots of any obstacles. It's called Ground-Based Detect and Avoid — the only system certified by the FAA to fly drones beyond visual line of sight."
The systems are located at Cannon Air Force Base, New Mexico, and Beale Air Force Base, California.
"We've also got a system housed in a bus that we could drive anywhere the Air Force wants it," Spurio said. "We can even tow a Low Power Radar behind us, and then set it up as our surveillance source."