Carrier Phase

Carrier phase is the measurement of the phase of a GNSS satellite’s carrier wave signal at a receiver, expressed in cycles or fractions of the signal wavelength. Unlike pseudorange observations, carrier phase measurements provide very high precision (millimeter level) but include an unknown integer number of whole wavelengths, known as the phase ambiguity.

In geodesy, carrier phase observations are the primary data source for high-precision GNSS positioning. They enable millimeter-level determination of station coordinates, crustal deformation, reference frame realization, and precise orbit determination. Resolving the integer ambiguities associated with carrier phase measurements is essential for achieving the highest positioning accuracy in geodetic applications.