What does DOP stand for in GNSS metrics?

• A. Dilution Of Precision
• B. Differential Optical Position
• C. Dynamic Orbital Parameter
• D. Data Observability Parameter

Answer: (A)

DOP is a measure of how satellite geometry affects the potential accuracy of a GNSS position. Dilution Of Precision captures how the arrangement of satellites in the sky amplifies or reduces the impact of the measurement errors you get from each satellite’s range. When satellites are spread widely across the sky, the geometry is good and the same measurement noise yields a smaller position error. When satellites cluster together or are low on the horizon, the geometry is poor and the position error can become larger even if the measurement noise is the same. Different DOP values describe different aspects of this effect: PDOP relates to 3D position, HDOP to horizontal accuracy, VDOP to vertical accuracy, and TDOP to time. In practice, lower DOP values mean better potential accuracy, while higher values indicate worse geometry. The other terms listed aren’t standard GNSS metrics, so they don’t describe how the satellite geometry influences position error.