What is a GNSS baseline?

• A. The vector between two GNSS receivers forming a portion of a network.
• B. The length of a satellite's orbit.
• C. The time difference between receiver clocks.
• D. The distance from a receiver to a satellite.

Answer: (A)

A GNSS baseline is the line segment, or vector, that connects two GNSS receivers in a surveying network. It describes both how far apart the antennas are and in which direction, usually expressed in a local coordinate frame like East-North-Up. This concept matters because by comparing the signals observed at both receivers, surveyors form differences that cancel many common errors, allowing a precise determination of the relative position between the two sites. The baseline is about the relationship between receivers, not about a satellite’s orbit, not about the time offset between receiver clocks, and not the distance from a receiver to a satellite.