Is there a way to know if the GPS can be used ?

For outdoor activities I need GPS for my app.

Before starting the timer I want be sure the GPS signal is good.

I check the GPS quality, when the quality is good I warn user that he can start the timer.

The issue is that a good signal quality doesn t mean that the signal is stable/reliable.

After 1, 2 or 5 seconds the quality can become poor, and the tracking is interrupted.

I note that when my device display the Garmin message "GPS ready", I don t loose the signal anymore.

So my question: is there a mean to know that the GPS is really ready?

How Garmin determines that the GPS is ready?

Should I wait a 5 or 6  QUALITY_GOOD during 10 or 20 seconds to be sure the signal is stable?