Variance–Covariance Matrix

The variance–covariance matrix is a statistical matrix that describes the precision and correlation structure of estimated parameters or observations. The diagonal elements represent the variances (precision) of individual parameters, while the off-diagonal elements represent covariances, indicating the degree of correlation between parameters.

In geodesy, the variance–covariance matrix is a fundamental output of least squares adjustment and other estimation techniques. It provides formal uncertainties of station coordinates, velocities, gravity field coefficients, Earth orientation parameters, and other geodetic quantities. Proper interpretation of the variance–covariance matrix is essential for assessing solution quality, combining multi-technique results, and ensuring consistency in terrestrial and celestial reference frame realizations.