GNSS Constellations are a network of time-synchronized satellite orbiting Earth used for Positioning, Navigation, and Timing. The first and most famous GNSS Constellation is Global Positioning System (GPS), developed and owned by the United-States of America (USA). Every Constellation emits specific signals, usable on Earth, Air and Space by enabled receivers to compute their position, navigate, or time-synchronize around the globe.
As the backbone of strategic and critical operations, many World key-players have developed and launched their own GNSS Constellations:
In addition, some countries have developed Geostationary Constellations (known as Regional Navigation Satellite Systems, RNSS), available only in specific areas of the world: