Dilution Of Precision (DOP) is a measure reflecting which factor most directly?

• A. Satellite geometry
• B. Receiver clock error
• C. Ionospheric delay
• D. Multipath

Answer: (A)

Dilution of Precision shows how the geometric arrangement of visible satellites affects the potential accuracy of the position solution. When satellites are well spread across the sky, their lines of sight provide strong, independent information, so the impact of measurement errors on the final coordinates is minimized, resulting in a low DOP. If the satellites cluster together or line up, the geometry is weak, errors are amplified in the solution, and DOP becomes high, signaling reduced precision. Other error sources like receiver clock error, ionospheric delay, and multipath exist, but DOP specifically reflects how satellite geometry influences how those errors translate into the position estimate. Different DOP values (for horizontal, vertical, or overall) all convey the same geometric idea: lower is better geometry, higher means the geometry is poor.