breautek edited a comment on issue #136: Offline Mode
URL: 
https://github.com/apache/cordova-plugin-geolocation/issues/136#issuecomment-463889615
 
 
   Using the GPS without having a mobile/wifi connection available will result 
your device relying solely on GPS satellites. It can take a really long time to 
receive a "GPS Fix" to the satellites. Even in perfect conditions, it can take 
upwards of 10-15 minutes for an average phone to get a satellite fix. Note that 
once, the phone has received the satellite fix, gps updates will become much 
more stable. The satellite positions will be cached, so the next time the GPS 
requires a fix, in theory should be a lot quicker from a "cold" startup. Note 
that this doesn't have anything to do with the library or the phone itself. 
This is simply how GPS satellites and hardware work.
   
   Ideal conditions is being outside, clear weather, open skies (no tall 
buildings/mountains). Things that can interfere with GPS signals is being in 
large buildings, poor/stormy weather, lots of physical objects in the way 
limiting the "sky visibility",  etc. The following documents may explain why it 
takes so long to start up better than I can:
   https://en.wikipedia.org/wiki/Time_to_first_fix
   https://gpslogger.app/gps-fix-details.html
   
   The reason GPS works quickly when internet access is available is because of 
"A-GPS" (Assisted-GPS) which completely skips the requirement to look for & 
connect to several satellites. So obviously, if possible, it's best to have an 
online connection, but if offline support is necessary then you'll need to be 
prepared for a lengthy period of time before the phone can begin receiving GPS 
events.
   
   I realize this is probably not an answer you were expecting, but I hope this 
information helps provide you a better understanding of GPS technology and in 
turn, help you make informed decisions in your app development.

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