GPS and Galileo?

[oeagleo]

From the Apple Watch Series 3 Website:
"Series 3 GPS + Cellular

• GPS, GLONASS, Galileo, and QZSS
• Barometric altimeter"

The question is how does one tell WHICH sat system the watch is using? Glonass is notoriously inaccurate, while Galileo is more accurate under difficult conditions, the limiting factor is the number of birds in the sky. Is there a way to "force" the AW to use one system over another? How does one tell when a sufficient "lock" happens, it simply cannot be instantaneous, as the 3-2-1 countdown would indicate.
Anyone have any ideas?

 

[bruinsrme]

US GPS
Galileo Europe
Glomass Russia
QZSS Japan

 

[iamasmith]

How does one tell when a sufficient "lock" happens, it simply cannot be instantaneous, as the 3-2-1 countdown would indicate.
Anyone have any ideas?

I'm not so sure about that, a handheld hiking GPS typically only has data from the satellites to work from so uses almanac data and, when it's finally been received, ephemeris data to finely pinpoint the birds and then there's extra in band data that may be received from systems like WAAS but all of these are low frequency in terms of being able to sync a channel and use that data.. that being said these receivers are still popular for a number of reasons.

A phone, or a cellular watch has some additional tricks that can be deployed if there's data available and coarse grain location available from wireless and cellular tower systems. It can use that data to acquire ephemeris data through the data service so can produce surprisingly fast cellular locks.

All that being said the presentation of a position may also be subject to an initial coarse lock and only refined later. In terms of experience the faster availability of location is going to be paramount and accuracy should catch up.