I don’t know about the receivers in phones but my understanding of gps is that it’s actually very slow to initialise if you don’t already have a rough idea of w

I don’t know about the receivers in phones but my understanding of gps is that it’s actually very slow to initialise if you don’t already have a rough idea of where you are. Roughly, I think you try to guess where you are and do some dsp work that will successfully separate signal from noise if you guessed correctly. You do this first for the ‘coarse navigation signal’ and again for the fine one. I think there are ways to improve it, eg testing multiple locations in parallel but I don’t know how much phones do those vs having good guesses (nearby cell towers, Wi-Fi, flights in your calendar can all be relevant signals to start with good guesses).