Thank you djtroyan and jrock!
I replaced the flex cable and the Wifi antenna bracket cover (though I doubt that I had a reason to do so) linked in Jrock's post.
This completely fixed my GPS issue that popped up sometime around the 9.2.1 release.
I had no GPS signal, like many of you, and now is is again working as it should be. I think that I was having some Bluetooth issues as well that I was blaming on my headphones, but it seems like it was my phone. That is gone too.
Release day AT&T iPhone 6 (64GB) like many of the posters here.
For the record, I tried just about every suggestion here, including jfoxtrot9's note about shared Apple IDs as I am using the same Apple ID on two iphones. Nothing fixed it.
The two parts and a set of repair tools cost me $20 shipped. Total repair time was about 30 minutes. It wasn't hard, just tedious at times.
iFixit guide was great.
No visible damage to the naked eye to the flex cable, but I wonder what I would see under a magnifying hood.
I'm so happy that I have a working iPhone again. Thanks for all of the suggestions in this thread!
Apple has some kind of a weird problem here that so many of us have tied to a software release, but fixed with hardware replacement.