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Egads, the news coverage of this is horrible fear mongering. The researchers from UT built a system to protect against GPS spoofing. In order to prove that the

Egads, the news coverage of this is horrible fear mongering. The researchers from UT built a system to protect against GPS spoofing. In order to prove that their protection system works, they had to demonstrate that GPS spoofing is feasible. Without exception, every news item on this only mentions the spoofing part, and not the protection part. Military unmanned systems use encrypted GPS that is not vulnerable to the attack demonstrated. Its possible to make a vehicle fly erratically, or even cause it to crash by spoofing GPS. But to take control requires a lot more than what was demonstrated. An error of 1us in the spoofed signal corresponds to 1000ft -- that's why the actual descriptions of the vehicle say 'banked hard' or 'veered' off course. GPS jamming is so much easier than spoofing and results in the same thing.

erikb 14y ago
Do you have some reasonable sources about GPS jamming? From what I know, GPS should be protected against jamming through signal spreading, which means you should be only able to do it with investing unreasonable amounts of resources.
- asynchronous13 14y ago
  Is this good enough? http://www.jammerall.com/categories/GPS-Jammers/ http://www.jammerall.com/categories/GPS-Jammers/ Low-cost GPS jammers are $30-$50 dollars, though they are illegal to sell or to use. Jamming is a simple matter of sending out a signal more powerful than the signal received from the satellites. 100mW transmitter is more than adequate in close range.
rabidsnail 14y ago
> GPS jamming is so much easier than spoofing and results in the same thing. Does it? Can't the drone tell that the GPS input that it's getting is inconsistent and fall back to flying home using dead reckoning?
- asynchronous13 14y ago
  Technically, yes it is possible for an autopilot to use dead reckoning for navigation without GPS at all. (we didn't use GPS to navigate to the moon, right?) However, all commercial autopilots that I know of rely on GPS to some degree. The difference is the use of low-cost gyros and accelerometers. They are good enough when augmented with GPS, but not good enough all alone. Edit: the low-cost sensors can be augmented with sensors other than GPS too, like vision processing. This has been demonstrated but is not yet in widespread usage. I expect to see this become more common due to demonstrated vulnerabilities in GPS.
  - jandrewrogers 14y ago
    State-of-the-art inertial navigation technology has approximately the same precision as state-of-the-art GPS. Even modern run-of-the-mill interferometer-based inertial systems are precise enough for most purposes. The unique value of inertial navigation is that it requires neither receiving nor sending a signal that can be jammed or spoofed, hence why the military uses it for everything.
    - Cushman 14y ago
      Out of curiosity, how precise are we talking? I assume the top-level military tech is classified, but if I buy off-the-shelf parts, how far can I fly and still land on the runway using pure dead reckoning?
    - asynchronous13 14y ago
      1960's inertial navigation systems have better resolution than today's consumer GPS. The issue is not the technology, it's the cost, size, and weight. The small, light, and low-cost sensors fueling the current wave of UAVs are not the most accurate technology available, but that doesn't mean they aren't useful.
      - einhverfr 14y ago
        The concern I would have with inertial navigation over long distances is the possibility of drift. You might have good resolution over short distances, but what about hours and hours? What if your vectors are not quite right, or you get drift in your gyros (and LR gyros are prone to drift in certain circumstances)?
lallysingh 14y ago
> GPS jamming is so much easier than spoofing and results in the same thing. If that drone is in a homogenous-looking area, say a desert with litte habitation, it wouldn't be hard to slowly get the drone to a different target than desired, possibly having it think another car or house is its target.

erikb 14y ago

Do you have some reasonable sources about GPS jamming? From what I know, GPS should be protected against jamming through signal spreading, which means you should be only able to do it with investing unreasonable amounts of resources.

asynchronous13 14y ago
Is this good enough? http://www.jammerall.com/categories/GPS-Jammers/ http://www.jammerall.com/categories/GPS-Jammers/ Low-cost GPS jammers are $30-$50 dollars, though they are illegal to sell or to use. Jamming is a simple matter of sending out a signal more powerful than the signal received from the satellites. 100mW transmitter is more than adequate in close range.

rabidsnail 14y ago

> GPS jamming is so much easier than spoofing and results in the same thing. Does it? Can't the drone tell that the GPS input that it's getting is inconsistent and fall back to flying home using dead reckoning?

asynchronous13 14y ago
Technically, yes it is possible for an autopilot to use dead reckoning for navigation without GPS at all. (we didn't use GPS to navigate to the moon, right?) However, all commercial autopilots that I know of rely on GPS to some degree. The difference is the use of low-cost gyros and accelerometers. They are good enough when augmented with GPS, but not good enough all alone. Edit: the low-cost sensors can be augmented with sensors other than GPS too, like vision processing. This has been demonstrated but is not yet in widespread usage. I expect to see this become more common due to demonstrated vulnerabilities in GPS.
- jandrewrogers 14y ago
  State-of-the-art inertial navigation technology has approximately the same precision as state-of-the-art GPS. Even modern run-of-the-mill interferometer-based inertial systems are precise enough for most purposes. The unique value of inertial navigation is that it requires neither receiving nor sending a signal that can be jammed or spoofed, hence why the military uses it for everything.
  - Cushman 14y ago
    Out of curiosity, how precise are we talking? I assume the top-level military tech is classified, but if I buy off-the-shelf parts, how far can I fly and still land on the runway using pure dead reckoning?
  - asynchronous13 14y ago
    1960's inertial navigation systems have better resolution than today's consumer GPS. The issue is not the technology, it's the cost, size, and weight. The small, light, and low-cost sensors fueling the current wave of UAVs are not the most accurate technology available, but that doesn't mean they aren't useful.
    - einhverfr 14y ago
      The concern I would have with inertial navigation over long distances is the possibility of drift. You might have good resolution over short distances, but what about hours and hours? What if your vectors are not quite right, or you get drift in your gyros (and LR gyros are prone to drift in certain circumstances)?

lallysingh 14y ago

> GPS jamming is so much easier than spoofing and results in the same thing. If that drone is in a homogenous-looking area, say a desert with litte habitation, it wouldn't be hard to slowly get the drone to a different target than desired, possibly having it think another car or house is its target.