Geometric Dilution of Precision (GDOP) (GDOP)

A dimensionless GNSS geometry factor combining three-dimensional position and receiver-clock uncertainty.

GDOP reflects how the relative positions of the satellites used in a solution amplify common ranging errors across latitude, longitude, height and time. It combines position dilution of precision and time dilution of precision, commonly by a root-sum-square relationship.

Low GDOP indicates favourable satellite geometry, while high GDOP indicates weaker geometry. It does not, by itself, quantify the receiver’s actual position or timing error.