Two things fix it for me. I first try going into settings>location> and uncheck, and recheck the first two options. Leave Verizon location services unchecked. If this doesn't work, then a reboot usually does.
I have Droid 3 with the latest update. The phone is not rooted.
I had chances to use the GPS and Navigation on my Droid 3, last week on round-trip, from Richmond, VA to Baltimore, MD, about 160 miles each way and this week while working in Austin, TX.
When it works, it works well. I do not feel the problem is heat related as my Droid 3 never got hot. While in the Dorid 3 OEM car dock, I used Motorola car charger that I purchased from VerizonWireless Online at the same time as the Car Dock, so charger compatibility should not be the issue.
1st impression. I have a Honda Element. I never had GPS or Navigation problems with My OG Droid. I place the Droid 3 car mount in the top of the dash, in the same location as the Droid 1. I lost the GPS signal twice.
The first time, I think was due to the 'northerly' direction in a heavily tree/leaf covered area. (It also impacted my satellite reception here). I moved it slightly towards the windshield and it immediately picked up the GPS signals. This shows me that the internal GPS hardware/antenna is not in the same position as the OG Droid.
The second time, all GPS was lost. The app "GPS Status" could not pick it up. I tried, going through menu/settings/locations and this did not work. Once I fully rebooted (fully powered down/powered on), it worked fine for the remainder of the trip up and back.
Driving around Austin, I encountered the problem 3 times.
The first one occurred when I tried picked up the Rental Car at the Austin, TX airport. Could not acquire the GPS signal. Naturally, I put the phone into Airplane mode and took it out of airplane mode when I arrived. Again a reboot was necessary (Full Power Down/Power On). This may indicate a problem with restarting GPS when the phone comes out of Airplane Mode.
Twice last night - going to dinner and then going to the hotel after dinner. For both of these (Again a reboot was necessary (Full Power Down/Power On). The first time I was using the Motorola car charger, the 2nd time I used a RocketFish (BestBuy brand) car charger.
Finally this afternoon (10/19/2011). I flew from Austin, TX to Richmond, VA. For grins or giggles, I turned Navigation on. I expected there to be a problem acquiring the GPS signal. Was I ever amazed when it locked quickly and remained connected for the 25 mile trip home.
From my perspective, there seems to be an app or service on my phone (it may be a 'factory' one or one I installed) that is causing the GPS to shut down. However, at this time, I have not been a good enough detective to figure it out.
Bob
I will let them replace this phone with another one and hope the replacement works better. It's such a shame that I picked the phone that didn't work, and my wife got the good one. But I guess she really needs the Navigate function more then I do............. I'll keep trying and watching for a solution.