A GPS receiver uses probably the most power of any peripheral in a mobile device, hence the system will send it to sleep whenever the opportunity arises.
When a GPS receiver is turned on it presumes that it is in the same place as when it was last turned off..... Hence it figures out quickly which satellites will be in view and starts looking for them. If some time has past, or the device has been moved to a new location then the device quits the quick-fix routine and reverts to looking for satellites from first principles. A successful quick-start can take maybe 10 seconds, the first principles fix can take 2-3 minutes.
Hence the expression - There is no such thing as a quick-fix

I'll get my coat......