What does PDOP measure in GPS technology?

Positional Dilution of Precision (PDOP) is a critical measure in GPS technology that indicates the accuracy of the position calculated by the GPS system based on the satellites being used for the fix. It assesses how the geometric arrangement of satellites affects the precision of the positional measurements.

When satellites are positioned widely apart in the sky, the PDOP value is lower, indicating a more accurate position. Conversely, if the satellites are clustered closely together, the PDOP value increases, suggesting that the positional accuracy is diminished. A lower PDOP value generally translates to higher confidence in the GPS-derived position, as it shows that the satellites are providing complementary data that together contributes to a more precise location determination.

Understanding PDOP is essential for assessing the quality of GPS measurements, especially in applications that require high precision such as surveying, mapping, and navigation.