> While modern GPS can get a position fix pretty quick
Can they? I have popular usb gps receivers and it still takes many minutes to get a lock on enough satellites to give accurate positioning. Given that it is dependent on things flying overhead in space, I don't think the receivers are where any "boot speed/signal lock" improvements can happen.
Mobile phones are no exception, they've just employed several tactics to make the perception seem as if it's instant.
They start with "course" location which is based of the geo data of the cell's ip address and vicinity to known wifi access ssids. They also know where you were at when the phone went into standby or was powered down, and can reasonably assume you haven't gone far away from that location without the accelerometer noticing movement of any kind (keep in mind most phones do not fully shutdown even when powered off). That's all a very good and pretty accurate starting point for when you fire up maps on your phone, and by the time it is a problem a "fine" gps signal is locked. And usually due to other system services (like network config, find my device, etc) firing up gps when you unlock your phone or some other privacy invading app running gps as a background task, there's usually a fine grained gps lock by the time you even open your maps app.
Modern GPS receivers are much faster. They can search for every possible satellite at every offset rapidly in parallel, meaning that they don't need the almanac in order to get a GPS lock quickly. They do still need the orbital data for each satellite being used, but that's transmitted by the satellite itself much more regularly than the almanac and mobile phones can generally speed things up even further by downloading a small amount of assistance data that contains orbits for all the satellites for the next day or so.
Can they? I have popular usb gps receivers and it still takes many minutes to get a lock on enough satellites to give accurate positioning. Given that it is dependent on things flying overhead in space, I don't think the receivers are where any "boot speed/signal lock" improvements can happen.
Mobile phones are no exception, they've just employed several tactics to make the perception seem as if it's instant.
They start with "course" location which is based of the geo data of the cell's ip address and vicinity to known wifi access ssids. They also know where you were at when the phone went into standby or was powered down, and can reasonably assume you haven't gone far away from that location without the accelerometer noticing movement of any kind (keep in mind most phones do not fully shutdown even when powered off). That's all a very good and pretty accurate starting point for when you fire up maps on your phone, and by the time it is a problem a "fine" gps signal is locked. And usually due to other system services (like network config, find my device, etc) firing up gps when you unlock your phone or some other privacy invading app running gps as a background task, there's usually a fine grained gps lock by the time you even open your maps app.