Celestial Sphere is mainly used in astronomy and navigation and is a very practical tool for positional astronomy.
This article demostrates an example which displays the Celestial Sphere and locations of visible GPS satellites with their signal-strength. The examplary code is attached with this article and it is really good and well-explained with comments. A quick overview for this example is also provided in this article.
This article can be very beneficial to intermediate and experienced developers who are working on GPS related applications.