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> A couple of seconds later they will send more accurate GPS coordinates for most calls

I wish my day-to-day GPS initialised and obtained an initial fix that quickly. Usually it needs at least five minutes, sometimes over an hour.

From an earlier job I vaguely remember that a NavStar cold-fix requires two or three minutes at a minimum with optimal conditions.



What is your day-to-day GPS? If it's a dedicated GPS device and not a cellphone, that might explain it.

Cellphones have Assisted-GPS where they get satellite orbit information and accurate time from the cellular network, and sometimes can offload computation to it, so they can get faster locks.

Apparently it was developed for 911 reasons - https://en.wikipedia.org/wiki/Assisted_GPS


Maybe you just need a new phone/device? With each new phone I had faster and faster GPS lock time.


Cellular devices can get rough location fixes very quickly because the cell towers cue them with assist data, plus they can download the satellite constellation ephemeris data in advance. Stand-alone GPS receivers are much slower since they lack all of those clues. And if the device was just powered on and hasn't gotten a fix near the current location within the past few hours then they can get really slow. If you take your cell phone out in a canyon somewhere with no cell coverage, turn it off for a few days, and then turn it to get a GPS fix expect it to take a while.


This is because just-GPS devices need to download ephemeris data from the satellites. Phones get it from the internet, which is much much faster.




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