The Earth's atmospheric dome is more than enough to bounce signals from one point to another, allowing trilateration of a receiver to be achieved. This just illustrates yet again the explanatory power and effectiveness of Flat Earth Theory. Equally valid and compelling explanations exist for the phenomenon we see. You dont need to keep your mind stuck inside a sphere. Forget science. Try THINKING for yourself in a free and unrestrained way. You might be surprised at the results. [spoiler]If you would like to see the full version of my post, check it out here: https://flatearthandthought.com/2017/01/27/gps-and-navigation-on-the-flat-earth/[/spoiler]