Satellite Navigation Systems, also known as Global Navigation Satellite Systems (GNSS), are systems that use satellites to provide positioning, navigation, and timing services to users on Earth. These systems use a network of satellites that orbit the Earth and transmit signals to receivers on the ground. The receivers then use the signals to calculate their exact location, speed, and direction. GNSS systems are used in a variety of applications, including aviation, marine navigation, surveying, and mapping.