When I first got the Hudl, I played with the GPS receiver, and was impressed by the number of satellites it managed to see (14 or 15). I put that down to having a receiver chipset with more than the 12 channels available in the SiRFStar-III equipped PDA I've had for a few years. Even then, I was a bit surprised that 15 GPS satellites were actually visible (given the size of the constellation and the sky view from any point on the Earth).
The other day, I played with the GPS Status app, and spotted that it was reporting Satellite Vehicle IDs (SVIDs) greater than 32. I guessed that it must be picking up GLONASS, and, reading the GPS Status user manual, that is indeed what it means for SVIDs between 65 and 92.
In reply to captain paranoia: I've considered this too, using my tablet as a GPS device when out and about. I'm not sure how practical it is though... my old nexus 7 has rubbish battery life and same for my Galaxy S3 phone.
If I use the GPS in either, the phone/tablet will most likely be dead after 3 or 4 hours, if not close to dead!
Your best bet is to probably root the device, and then stop all un-needed functions that run in the background so that it becomes a GPS-only device when you want it to.
I have a solar panel that I use sometimes, mostly only when camping or travelling to try and get some extra juice. The decent ones are expensive though. You can also get USB battery packs that take standard AA batteries