I can get a stable GPS lock on my drone on my workbench, no problem.
When I go outside in an open area, on initial power up I can’t get a GPS lock.
I have waited 10 minutes, no lock.
However, if I repower the drone, It gets a GPS lock immediately.
From that point on it will get a GPS lock every time.
I am using the Navio2 GPS/GNSS.
The firmware is whatever the latest Navio2 stuff is. Downloaded less than 3 weeks ago.
It’s an old F450 frame and motors.
There is a metal plate sandwiched between the plastic for a ground plane.
It looks weird, but it seems that it just needs more time for a GPS lock in a new location. I see you’ve mentioned that you did tests in an open area. However, I just want to point out that a view angle above the horizon matters as well.