Anyone else had this issue? I'm running IOS7 on an iPad 3 with no GPS. I use a Glonass 2000 receiver and bluetooth it to the iPad. The iPad is secured to my knee and the receiver is suckered onto the top part of the windscreen.

Not the first time it has happened but I was returning from Breighton last sunday and couldn't get the iPad to pick up a signal. I was taxiing out at the time so didn't have time to faff around with it but once in the cruise I tried shutting down the iPad and restarting-didn't work. I tried turning the bluetooth on and off, that didn't work (my passenger was a pilot so I handed over control to her while I was sorting it).

I tried turning the Glonass 2000 off and on, that didn't work either. I was getting a banner sign 'Searching for location' rather than 'Searching for satellites'. I had the wireless turned off so I know it wasn't searching for hotspots. All of a sudden it decided to play and was OK for the rest of the flight home. It's happened quite a few times now and in different aircraft, anyone any ideas? Is there a 'switch on procedure' I should follow?