DOP – Dilution of Precision

Dilution of Precision (DOP) is a dimensionless measure that quantifies how satellite geometry affects the precision of GNSS position and time estimates. It describes the amplification of measurement errors due to the spatial distribution of satellites relative to the receiver. Different types include GDOP (geometric), PDOP (position), HDOP (horizontal), VDOP (vertical), and TDOP (time).

In geodesy, DOP values are used to assess the quality of GNSS observation geometry and to optimize station design and observation scheduling. Favorable satellite geometry (low DOP values) improves positioning accuracy, which is critical for high-precision applications such as reference frame realization, crustal deformation monitoring, and precise orbit determination.