Chinese launch encrypted GPS
A Chinese company is launching an independent GPS service with a secondary, encrypted signal that can be used (presumably) by the military. There's a couple interesting applications for this -- for example, you could spoof the unencrypted GPS and foil guerrillas or enemy fighters while your forces remained correctly geolocated. You could even locally spoof GPS signals to give persistently wrong info about the location of sensitive installations while ensuring that your own people had good location data. Of course, this all goes to pieces if the adversary has a second GPS keyed into a rival system like Galileo or the US system.
In presentations April 23 here at the Toulouse Space Show, these Chinese officials nonetheless said their global Compass/Beidou system would be fully compatible with the U.S. GPS, European Galileo and Russian Glonass global navigation constellations.Link (via /.)Like GPS, Galileo and Glonass, Beidou/Compass would be free of direct user charges but also feature an encrypted signal for authorized users only, presumably including the Chinese military.
Chengqi Ran, vice director of the China Satellite Navigation Project Center, said the secure Beidou/Compass signal would be "a highly reliable signal dedicated to complex situations."
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This is, of course, the same strategic policy the US military had when it created the Global Positioning System. In fact, it originally deliberately introduced errors into the unencrypted GPS channels to reduce accuracy. I think this is no longer the case, though.
My father works for one of the contractors which developed GPS in the first place, and I remember thinking it was extremely cool when my dad borrowed a military issue "crypto keyed" receiver for family vacations.
Spike, you are right after September 18th, 2007, the US DoD stopped procuring satellites with the ability to purposely degrade the precision of civilian GPS signals.
I wrote about this subject in depth on my blog: http://www.gps.eu/how-the-government-enhances-gps-performance/
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Although there are many interesting things one could do with a GPS signal with encrypted side channel, persistently skewing measurement in one area through spoofing would be hard.
GPS and similar geolocation systems work through precise time-of-flight measurements using broadcast time signals from atomic clocks in satellites. Receivers get both satellite location information and "what time is it" information from each satellite. To spoof this in a way that would be seamless for a receiver moving into the distorted location, you'd need to produce a more powerful spoofed signal with distorted time or trajectory information that would match the currently available constellation of satellites well enough that the GPS receiver wouldn't loose its fix. You'd also want to keep the overall time signal close enough that local time wouldn't appear to jump too much.
If you don't care about the problem of what happens when the receiver moves into or out of the distorted region or matching the current time, you can broadcast whatever kind of spoofed signal you want, but this may not be very convincing for an adversary who was paying attention. It would be a lot easier just to locally jam the signal.
I give it 3 days before someone's decrypted the military side of it. Probably a 14-year-old in Belarus.
LORAN, FTW!
The US system has always had a similar capability.
Probably the reason they'd be launching it is so that they are not vulnerable to the US turning off the unencrypted GPS service. (Even if we no longer deliberately degrade the open service, I bet it can be turned off at a moment's notice.)
As to the Galileo system, if the EU ever fails to turn it off on US demand, the US DoD has threatened to shoot down their satellite network. (I can imagine some scenarios where that wouldn't be entirely unreasonable, though they may not be too likely.)
This would only make sense if the Chinese system was the only one available. So are policy-makers in China seriously considering removing US and Euro GPS satellites?
...Talk about moving from a cold to hot war in instants.
Seems foolish, yet why would they develop their own system with an encrypted channel (having their own system makes sense, it's the latter that's interesting).