🛰️What is GNSS?

GNSS stands for Global Navigation Satellite System. It represents a group of satellites that can be used for positioning, navigation or timing. While GNSS is the general term for any satellite constellation of that sort, you may have heard of the nation-specific systems:

• Global Positioning System (GPS) owned and operated by the United States

• Galileo (GAL) owned and operated by the European Union

• BeiDou Navigation Satellite System (BDS) owned and operated by the People's Republic of China

• GLONASS (GLO) owned and operated by the Russian Federation

• Indian Regional Navigation Satellite System (IRNSS) / Navigation Indian Constellation (NavIC) owned and operated by the Government of India

• Quasi-Zenith Satellite System (QZS) owned by the Government of Japan and operated by QZS System Service Inc. (QSS)

How does GNSS work?

To give you a short introduction into how GNSS works in general, these are the main points:

• A satellite sends its signal to the earth, providing information about their location and precise time of when the signal was sent.

• The signal travels through space at the speed of light.

• A GNSS receiver picks up the signal and notes the precise time of the signal's arrival.

• With the information about the travel time of the signal from the satellite to the receiver, we are able to calculate the distance between the satellite and the receiver.

• The position of the GNSS receiver is calculated with distances to at least four satellites.

• The accuracy of this basic GNSS principle is around a few meters.

Why does GNSS have multiple signals?

When you browse our explorer, you can see how many signals a station provides. A satellite sends on multiple signal bands, these are called e.g. L1, L2 and L5.

Receiving multiple signals is beneficial to reduce the errors occurring from the ionosphere, a layer of the atmosphere between the satellite and receiver. Additionally, the accuracy can be higher and you can get a faster RTK fix. Find more information on why multiple signals are beneficial on Septentrio's wiki page.