Time Dilution of Precision (TDOP) (TDOP)

A dimensionless GNSS geometry factor describing how ranging errors are amplified in the receiver-clock estimate.

A GNSS receiver solves for its clock offset as well as position because its clock is not synchronised as precisely as the satellites’ atomic clocks. TDOP expresses the geometric contribution to uncertainty in that time solution.

Lower TDOP generally indicates stronger geometry for estimating clock offset, but it is not a direct statement of timing accuracy. Signal propagation, receiver behaviour, corrections and other error sources must also be considered.