Problems with synchronization

I have Canopy Wireless at 5,7 GHz. My hub consists of 3 AP and 1 BH. Recently I started having problems with my GPS. It can track down only one satellite. I had to adjust AP to generate synchronization for my system. What can be the problem with GPS? What is better, to have one AP to generate and other to listen or all AP to generate synchronization? In that case, should I disconect GPS?

Check your all cables first, your GPS antenna installation (does this have a clear sky view?) and check the status on the CMM. The cable length to the GPS antenna should not exceed 30 meters!
If you are running an AP cluster it is not possible to let one/all AP('s) to generate sync unless you can provide enough channel separation. Try to fix your CMM installation first.