A low HDOP (Horizontal Dilution of...

🔍 Key Concepts

• HDOP (Horizontal Dilution of Precision) describes the geometry/relative positions of the GPS satellites used for a fix • Lower DOP (Dilution of Precision) numbers generally mean better geometry and therefore more reliable positions • Be careful to distinguish between signal quality (strength/interference) and position quality (accuracy of the fix)

💭 Think About

• Ask yourself: when satellites are well spread out in the sky, does that usually improve or worsen position accuracy? How would that affect the HDOP number? • Which answer choices refer to the quality of the radio signal itself, and which refer to the quality of the position/fix you get from that signal? • Think about this rule of thumb: are mariners generally happier to see a high DOP value or a low DOP value on their receiver?

✅ Before You Answer

• Identify which options talk about signal quality vs. which talk about the fix/position quality • Recall that lower DOP values correspond to better satellite geometry and thus better potential accuracy • Make sure the choice you pick matches both: low HDOP value AND what that implies for the resulting position

A low HDOP (Horizontal Dilution of Precision) number such as 2 indicates a __________.

poor signal quality

good signal quality

good fix

poor fix