A modern GPS does a few things to test itself and verify that everything works. Once the system loads there are a few things for you to do to make sure it is ready to go. For this post, I will use a Garmin 530. Other GPS systems may vary somewhat in how they operate. Make sure the battery and… Read more: https://schaeferflight.com/index.php/2018/04/28/how-to-do-your-gps-self-test/