What happens to drone if GPS is fed wrong location data ?

[Paci Fista]

Driving my car near to a US Embassy in a foreign country some time ago I noticed that my Google Maps application on my phone was showing my position in another location, half a kilometer or so away from my actual position, on another street altogether. I passed again the next day, same thing happened. Away from the Embassy, and the problem solved itself. I looked up the issue and found that the actual satellite signals are never to be tampered with (except in war situations I suppose), but today saw a demonstration video on Youtube where a UK guy showed how to use a 'RFHack' device to successfully position his phone/Maps in Kansas... So I guess the technology is around and used to screen off potential targets from GPS-led attacks.
I don't intend to fly my drone around any Embassy, but, just out of interest, what would happen to a flight in case some jokers (or law enforcement) start using this hack with powerful antennas and you happen to fly in their beam ? Technical comments also welcome.

 

[zocalo]

Interesting question, with a particular relevance to certain groups in the Middle East at present, I suspect, so kinda topical too.

If we're specifically talking about spoofing GPS, rather than the RF bands used for comms with the RC, then I can't see it having any effect on collision avoidance (that is optical and local to the drone), and the drone will fly quite happily without a GPS lock in any event. Realistically, that would mean that the only real impacts would be that it would indicate an incorrect position (and maybe bearing too?) on your RC screen, and the IPTC GPS data on any images would obviously be off as well. The only thing I can see that might have issues would be if you passed through such an zone while doing an RTH, but even then I'd assume it would adjust course once it cleared the area. Mess with the RC comms as well though, and I'd expect it to respond as with any loss of comms scenario and attempt an automatic RTH, which will then have issues until it clears the area of interference.

FYI, I read an article some time ago about ships passing near one of those Chinese military bases created on a South China Sea island all suddenly finding GPS showed them at the same point 50km or so away (and in-land to boot!), yet it was taken as more of a curiousity than a navigation hazard. GPS might be a US system, but they're definitely not the only ones capable of spoofing it.

 

[sar104]

At least one country has been confirmed to use GPS spoofing in the vicinity of certain facilities, and it's likely to be more common than realized. If you were to fly a DJI aircraft into such a situation then it would cause a GPS Position NoMatch IMU error. If that persisted then the aircraft would switch to ATTI mode.

 

[anotherlab]

Driving my car near to a US Embassy in a foreign country some time ago I noticed that my Google Maps application on my phone was showing my position in another location, half a kilometer or so away from my actual position, on another street altogether. I passed again the next day, same thing happened. Away from the Embassy, and the problem solved itself. I looked up the issue and found that the actual satellite signals are never to be tampered with (except in war situations I suppose), but today saw a demonstration video on Youtube where a UK guy showed how to use a 'RFHack' device to successfully position his phone/Maps in Kansas... So I guess the technology is around and used to screen off potential targets from GPS-led attacks....

The Russians have been doing this whenever Putin visits somewhere sensitive. The BBC reported last year that a non-profit think tank documented over 10,000 distinct GPS spoofing incidents conducted by Russia. This causes havoc with commercial shipping.

...I don't intend to fly my drone around any Embassy, but, just out of interest, what would happen to a flight in case some jokers (or law enforcement) start using this hack with powerful antennas and you happen to fly in their beam ? Technical comments also welcome.

If someone is spoofing the GPS signals, it's not going to be in a tight beam. If you are within the radius of their range, your GPS receivers will be affected.

 

[zocalo]

At least one country has been confirmed to use GPS spoofing in the vicinity of certain facilities, and it's likely to be more common than realized. If you were to fly a DJI aircraft into such a situation then it would cause a GPS Position NoMatch IMU error. If that persisted then the aircraft would switch to ATTI mode.

Depends on the approach. If the system is jamming GPS, then this is what I would assume would happen too, but OP's post was more about spoofing GPS. In that case, the receiver still appears to be getting valid GPS data, only it's either a fixed location somewhere else (as was the case with the Chinese example I gave above), or on more advanced systems will be offset by a given amount (which later Chinese systems appear capable of doing).

Either way, I don't think it's going to cause the drone to fall out of the sky - it'll either switch to ATTI or just report its position incorrectly while in the zone of influence, with collision avoidance and flight controls continuing to function as normal. Besides RTH, the only scenario where I can see this potentially being a problem is if you are flying a waypoint mission BVLOS and not paying attention - in all other situations you should still be able to safely bring the bird home manually quite easily. Even if you're BVLOS, as long as you don't panic and have a reasonable idea where you are in relation to the drone and of the lay of the land, then you should be able to use the camera to navigate back to a point where you can bring it home, using ATTI mode the whole way if need be.

 

[sar104]

Depends on the approach. If the system is jamming GPS, then this is what I would assume would happen too, but OP's post was more about spoofing GPS. In that case, the receiver still appears to be getting valid GPS data, only it's either a fixed location somewhere else (as was the case with the Chinese example I gave above), or on more advanced systems will be offset by a given amount (which later Chinese systems appear capable of doing).

Either way, I don't think it's going to cause the drone to fall out of the sky - it'll either switch to ATTI or just report its position incorrectly while in the zone of influence, with collision avoidance and flight controls continuing to function as normal. Besides RTH, the only scenario where I can see this potentially being a problem is if you are flying a waypoint mission BVLOS and not paying attention - in all other situations you should still be able to safely bring the bird home manually quite easily. Even if you're BVLOS, as long as you don't panic and have a reasonable idea where you are in relation to the drone and of the lay of the land, then you should be able to use the camera to navigate back to a point where you can bring it home, using ATTI mode the whole way if need be.

I was referring to spoofing rather than jamming. Jamming won't cause the IMU error - just an immediate switch to ATTI. Spoofing will cause an IMU error and a delayed switch to ATTI.