What does 'constellation' refer to in the context of GNSS?

In the context of Global Navigation Satellite Systems (GNSS), 'constellation' refers specifically to the complete set of satellites that make up the system. This includes all operational satellites that are in orbit and capable of transmitting signals to receivers on the ground. The characteristics of the constellation, such as its number of satellites and their arrangement in space, determine the accuracy, reliability, and availability of positioning information.

Having a full constellation ensures sufficient coverage of the Earth's surface, enabling users with GNSS-enabled devices to receive signals from multiple satellites simultaneously. This multi-satellite reception is essential for calculating precise locations and for improving navigation and timing accuracy.

While the arrangement of satellites in the sky is related to the concept of a constellation, it does not fully capture the idea that the constellation must be a complete and operational set of satellites. Additionally, the network of control stations and the ground-based GPS receivers support the function of a GNSS but are not part of what constitutes a constellation in this specific context. Thus, referring to the complete set of satellites is the most accurate definition of 'constellation' in GNSS.