I've been testing various GPS/GNSS antennas indoors for the past year, and unless you're in a multistory building or have a full metal roof, there's a good chance you'll pick up 4+ satellites, good enough for a decent time.
But it can come and go, especially as there are other sources of interference in the 1-1.5 GHz range indoors, and reflections off various surfaces and objects make the signal way harder to distinguish.
But for by far the best chance of success, you should have the antenna outside, ideally with a clear view of most of the sky.
If inside, you could put it near a window or exterior wall, but a lot of modern construction materials can block things pretty badly.
But it can come and go, especially as there are other sources of interference in the 1-1.5 GHz range indoors, and reflections off various surfaces and objects make the signal way harder to distinguish.
But for by far the best chance of success, you should have the antenna outside, ideally with a clear view of most of the sky.
If inside, you could put it near a window or exterior wall, but a lot of modern construction materials can block things pretty badly.