Fundamentals of Surveying (FS) Practice Exam

What occurs when there is an increasing value for PDOP?

1. more multipath errors

2. a decrease in positional accuracy

3. a greater number of visible satellites

4. an increase in positional accuracy

The correct answer is: a decrease in positional accuracy

When there is an increasing value for Position Dilution of Precision (PDOP), it indicates a decrease in positional accuracy. PDOP is a factor that quantifies the effect of satellite geometry on the precision of a positional solution derived from satellite signals. A higher PDOP value arises when satellites are positioned closely together in the sky, resulting in less effective triangulation. This geometry can lead to larger potential errors in the positional calculations, making the data less reliable. On the contrary, a lower PDOP value signifies that the satellites are well-distributed across the sky, leading to improved positional accuracy. Therefore, when PDOP increases, it directly correlates with a degradation in the accuracy of the positioning information obtained from the satellites.