GPS on iPhone 6 is not accurate or working at all 1 week ago my GPS worked very accurately on Google Maps. But now it's very inaccurate, seems like it works using 3g connection.

What steps i did:


Restarted phone; 
Reset network/location privacy settings;
turned off then turned on location service;


But none of this helped me. Any advices?
It was broken GPS antenna, just replaced it and it worked again.