The Iranians claim they did this.
Frankly, I doubt it. The GPS signal used by the military is encrypted. Unless they broke the encryption, they won't be able to spoof it.
And frankly, I doubt they broke the encryption -- even if they somehow got their hands on a device that uses the encrypted code. It's standard to use one-way encryption -- i.e. you might be able to decode it, but you can't generate an encrypted message that will be accepted.
The article said that EVERYTHING BUT GPS was encrypted. So they just attacked the weak point.
I know it’s kind of shocking to me. But that thing was completely in tact...no way they got it by accident.