Drones look to the stars to make themselves stealthier

a circle of light seen in the night sky among bright stars
U.S. Marines with Air Combat Element, Marine Rotational Force – Darwin operate an uncrewed RQ-21A Blackjack at Bradshaw Field Training Area, Northern Territory, Australia on Aug. 13, 2020. (Image credit: U.S. Marine Corps photo by Cpl. Harrison Rakhshani)

A new celestial navigation system designed for drones could make them harder to detect by eliminating the need for GPS signal emissions.

Scientists from the University of South Australia have developed a new navigation system that allows uncrewed aerial vehicles (UAVs) — or drones, as they're more commonly known — to sense their location based on the stars in the night sky.

Such a system could make drones harder to detect and more resistant to jamming attacks that deny or disrupt GPS signals, one of the most common forms of long-distance navigation and positioning.

Using stars to navigate drones - YouTube Using stars to navigate drones - YouTube
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Celestial navigation, as this technique is known, has been used by humanity for thousands of years. Aircraft and spacecraft have used similar systems for decades, but this new system is designed to be low-cost and lightweight enough to be used on smaller drones, according to the researchers developing it.

"Unlike traditional star-based navigation systems, which are often complex, heavy and costly, our system is simpler, lighter and does not need stabilization hardware, making it suitable for smaller drones," said Samuel Teague of the University of South Australia (UniSA), in a statement.

The new system combines visual observations of the stars with standard autopilot technologies. In tests of the system using a fixed-wing UAV, researchers were able to pinpoint the drone's position within 2.5 miles (4 kilometers).

Such a capability could be used to operate drones in areas where GPS signals are jammed or degraded due to electronic warfare. This type of warfare targets the electromagnetic spectrum, through which radio signals and other emissions pass.

The researchers behind this new celestial navigation system say it could help not only with military missions, but also in peacetime operations like Earth observation.

"We have developed a navigation method that’s resilient, independent of external signals, and achievable with low-cost, easily accessible components. This makes it applicable to a variety of UAVs, from commercial drones to more advanced defense applications," UniSA scientist Javaan Chahl said in the statement.

"For instance, in environmental monitoring over remote locations or long-endurance surveillance missions where GPS might be unavailable or compromised, this technology offers a valuable new capability," Chahl said.

Russia has repeatedly jammed GPS signals in Ukraine throughout its nearly three-year invasion of the nation, using mobile jammers mounted on trucks. The U.S. Space Force has been developing and testing similar systems of its own.

But on the other hand, the capability to operate drones without the need to transmit and receive GPS signals could make it harder for militaries and other security forces to detect and defend against UAVs.

Several high-profile drone incursions above military facilities or sensitive facilities like nuclear power plants have shown that UAVs are already skirting air defense systems and pose a new threat for which there is no easy solution.

And as the ongoing war in Ukraine shows, the future of air warfare will likely move away from large, expensive fighter jets crewed by human pilots and toward smaller, less expensive drones that are easy to replace.

With that being the case, creating small, inexpensive celestial navigation systems will likely only accelerate the already-burgeoning future of drone warfare.

This research was published last month in the journal "Drones".

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Brett Tingley
Managing Editor, Space.com

Brett is curious about emerging aerospace technologies, alternative launch concepts, military space developments and uncrewed aircraft systems. Brett's work has appeared on Scientific American, The War Zone, Popular Science, the History Channel, Science Discovery and more. Brett has English degrees from Clemson University and the University of North Carolina at Charlotte. In his free time, Brett enjoys skywatching throughout the dark skies of the Appalachian mountains.

  • Unclear Engineer
    I don't think GPS navigation systems that receive the satellite signals emit any signals, themselves. They only need to detect the signals from the GPS satellites.

    And, I don't think that 2.5 mile accuracy is adequate for military targeting purposes.

    But 2.5 miles is pretty good accuracy for a person on a boat with a sextant. Of course, the person with the sextant has more time available than a drone moving at high speed.
    Reply
  • Meteoric Marmot
    Unclear Engineer said:
    I don't think GPS navigation systems that receive the satellite signals emit any signals, themselves. They only need to detect the signals from the GPS satellites.
    I expect that the emitted signal from GPS navigation systems isn't a result of intentional transmission, but rather is leakage from the local oscillator that is used to down-convert (heterodyne) the GPS signal to a frequency range where it can be processed.

    This technique is what police radar detector detectors use in areas where radar detectors are illegal.

    Given the highly-integrated nature and size of modern GPS receivers, I'm surprised that there is significant leakage at all. Moreover, I would expect any leakage to be largely directed upward as that is the direction the antenna(s) are facing.

    The other factor is that the onboard computer controlling the drone is likely emitting its own spectrum of radio noise so I don't see why that isn't also an issue -- one that will be common to any navigation method.
    Reply
  • Unclear Engineer
    I would also think that local jamming devices would be easier to detect and target than simple receivers.
    Reply