What term indicates your GPS receiver is using satellites with the best positional dilution of precision?

• A. positional dilution of precision
• B. horizontal dilution of precision
• C. vertical dilution of precision
• D. geographic dilution of precision

Answer: (A)

Understanding how satellite geometry affects position accuracy is key here. Dilution of precision (DOP) tells you how the geometry of the satellites translates into potential position error. The term that covers the overall 3D position accuracy is positional dilution of precision. When this value is low, satellites are well spread out in the sky, giving the best possible geometry and the smallest potential error in your position fix.

Horizontal DOP and vertical DOP refer to specific parts of the position—horizontal plane accuracy and altitude accuracy, respectively—so they don’t indicate the best overall 3D geometry. Geographic DOP isn’t a standard GPS metric, so it wouldn’t signal the best positional precision.