Chinese scientists use Starlink signals to detect stealth aircraft and drones

Starlink
(Image credit: Starlink)

Stealth aircraft, such as the F-22 and F-35, are designed to evade conventional radar systems located on the ground, but they are detectable from space. Chinese scientists have successfully used Starlink satellite signals to detect a stealth target during a radar experiment in the South China Sea. This new method could be applied to future military technology and stealth aircraft detection, reports the South China Morning Post

In the experiment, a DJI Phantom 4 Pro drone, roughly the size of a bird, was used to simulate a stealth aircraft. The radar cross-section of the drone was similar to that of actual stealth fighters. But instead of relying on traditional ground-based radar emissions, the drone was detected by analyzing electromagnetic signals from a Starlink satellite passing over the Philippines. 

The detection method relies on forward scatter, where an object like a plane or drone disrupts electromagnetic waves from a satellite, causing small signal disturbances, which are captured and analyzed to determine the object's location. This technique does not require the radar to emit signals, making it harder for adversaries to detect or jam. The experiment detected fine details of the drone, including rotor movements, despite challenges like the small antenna and low altitude. The researchers used an undisclosed algorithm and an unspecified high-performance processor to process the captured signals. While the method is still in development and not ready for military use, the technology shows potential for detecting drones and stealth aircraft. 

With over 6,000 satellites in orbit, Starlink's satellite network is vast, emitting high-frequency signals to provide extensive coverage. Although these signals are encrypted and not available to customers in China, the research team managed to build a receiver using commercially available components to capture and process the data. 

Traditional stealth aircraft are designed to evade radar detection using special materials and shapes to reduce electromagnetic wave reflections. Meanwhile, drones are usually too small for conventional radar to detect them. However, the Chinese experiment showed that using third-party satellite signals like those from Starlink can bypass these stealth features, making it possible to detect such aircraft regardless of their design. 

This experiment is part of China's efforts to enhance its anti-stealth capabilities. Other approaches include using large satellite constellations, over-the-horizon radars, and advanced anti-stealth radar systems on warships, all aimed at countering any U.S. military presence in the region.

Anton Shilov
Contributing Writer

Anton Shilov is a contributing writer at Tom’s Hardware. Over the past couple of decades, he has covered everything from CPUs and GPUs to supercomputers and from modern process technologies and latest fab tools to high-tech industry trends.

  • Rdslw
    I dont think starlink is necessary mention here, as it should work the same with any EM wave emiter that is abundant in the wild. Issue is range and how many antenas, and how much compute you need for it.
    for me it feels like it depends on very short range effects, so it would use a lot of compute 24/7 to warn you when you are already dead.
    Reply
  • bit_user
    Rdslw said:
    I dont think starlink is necessary mention here, as it should work the same with any EM wave emiter that is abundant in the wild.
    Like what, pulsars? Seriously, I think the idea is that it needs to be in orbit above the thing you want to detect. I doubt the spectrum of pulsar emissions would work for this.

    Starlink satellites aren't just orbiting in a haphazard way, they're orchestrated to fly in orbits that space them somewhat evenly over the territories they're meant to cover.

    Rdslw said:
    Issue is range and how many antenas, and how much compute you need for it.
    for me it feels like it depends on very short range effects, so it would use a lot of compute 24/7 to warn you when you are already dead.
    Synthetic aperture radar has always relied on significant amounts of computation, so that's nothing new to the field. This was probably prototyped on a GPU or FPGA. For deployment, they could use a FPGA or even a custom ASIC, in order to achieve the necessary compute performance.

    The idea is probably that they'd position these monitoring stations far enough away from targets that they would have advanced warning before the bombs started falling.

    I think a key piece of information we don't know is how far off-oxis the aircraft can be, in order to be detected. I assume it doesn't have to fly directly in between the satellite and the receiver, but presumably it can't be too far off the axis between them. So, one key question is just how far?
    Reply
  • magbarn
    Let's say the Taiwan issue came to a head, couldn't the US government just force Starlink to shut down?
    Reply
  • Specter0420
    So the government just tells Musk he needs to disable the transmissions as they orbit over certain locations at certain times... That may tip China off, but there are ways around that like random outages before the attack. However, China is launching their own constellation system and it'll probably be more purpose driven for these types of uses.
    Reply
  • bit_user
    magbarn said:
    Let's say the Taiwan issue came to a head, couldn't the US government just force Starlink to shut down?
    Maybe, but that seems a bit drastic. Millions depend on Star Link, including for things like emergency services.

    What I was wondering about is whether the satellites can just go silent above sensitive areas. It seems this little trick depends on them continuously transmitting.

    Of course, that only helps as long as other constellations of satellites can't be used. I think China is already planning (maybe even started?) launching a fleet of its own low-altitude satellites. Plus, I wonder how many other satellites can be used, or is there something fairly specific to Star Link satellites, like the RF band they use?
    Reply
  • edzieba
    RF Shadow / forward-scatter bistatic and multistatic RADAR has been known for decades, and demonstrated years ago. As long as you have a consistent background source, the technique works. Starlink is nice because its a consistent overhead source, but other sources such as weather RADAR, over-the-horizon emissions (e.g. terrestrial TV and radio), and so on. There are other satellite constellations that can act as RF sources, e.g. Oneweb, Iridium, the various and growing SAR constellations (these are nice because they are VERY high power RF sources), etc.
    magbarn said:
    Let's say the Taiwan issue came to a head, couldn't the US government just force Starlink to shut down?
    Given how vital it has proven to be for Ukraine's continued connectivity, and how likely China is to attempt to disrupt undersea telecomms cables to Taiwan, that would be a poor strategic move.
    Reply
  • Mattzun
    edzieba said:
    RF Shadow / forward-scatter bistatic and multistatic RADAR has been known for decades, and demonstrated years ago. As long as you have a consistent background source, the technique works. Starlink is nice because its a consistent overhead source, but other sources such as weather RADAR, over-the-horizon emissions (e.g. terrestrial TV and radio), and so on. There are other satellite constellations that can act as RF sources, e.g. Oneweb, Iridium, the various and growing SAR constellations (these are nice because they are VERY high power RF sources), etc.

    Given how vital it has proven to be for Ukraine's continued connectivity, and how likely China is to attempt to disrupt undersea telecomms cables to Taiwan, that would be a poor strategic move.
    China already has an over the horizon radar which should have a similar ability to detect stealth aircraft.

    It is possible that using Starlink provides better coverage of the approaches to Taiwan, but this seems more like a cheap proof of concept than a military system. China would probably launch its own cheap satellites with a consistent rf source if it depended on the capability. They would probably get better results if the satellite wasn’t providing internet.
    Reply
  • pixelpusher220
    Another thing that blankets many modern battlefields is cellphone coverage. You can do the same thing with those signals and is I think the posited reason the F117 was downed in Bosnia years ago.

    We target comms infrastructure first for multiple reasons. Spot on comments about US 'turning off' Starlink as well as the fact that China's home grown 'Starlink' system will be built for such uses.
    Reply
  • bit_user
    edzieba said:
    Given how vital it has proven to be for Ukraine's continued connectivity, and how likely China is to attempt to disrupt undersea telecomms cables to Taiwan, that would be a poor strategic move.
    That occurred to me, as well. However, do you think Taiwan is really putting all its eggs in the Starlink basket, for this? Did they not invest in their own comms satellites, as a fallback for their undersea connections getting severed?
    Reply
  • edzieba
    bit_user said:
    That occurred to me, as well. However, do you think Taiwan is really putting all its eggs in the Starlink basket, for this? Did they not invest in their own comms satellites, as a fallback for their undersea connections getting severed?
    They have cohosted payloads on GSO satellites (ST-2), slots on other GSO satellites (INTELSAT, ASIASAT) and OneWeb coverage. The GSO links are relatively low bandwidth compared to national needs (and not suitable for mobile applications), and Onwewebn are still in the process of building out their initial constellation, and has not been tested in an actively hostile environment. More diversity and bandwidth is preferable to less.
    Reply