DGPS performance is represented as 10 meters with which probability?

DGPS performance is represented as 10 meters with which probability?

• A. 10 meters with 95% probability
• B. 5 meters with 99% probability
• C. 10 meters with 99.7% probability
• D. 15 meters with 90% probability

Answer: (C)

DGPS accuracy is described by a radius around the reported position that is expected to contain the true position with a certain probability. In many navigation applications, errors are treated as roughly Gaussian, so about 68% of errors fall within one standard deviation, 95% within two, and 99.7% within three. Saying the performance is 10 meters with 99.7% probability means the true position lies within 10 meters of the DGPS fix in 99.7% of cases—that’s a three-sigma bound. This is the standard way to express DGPS accuracy, pairing a distance with a high confidence level. Other options mix different distances and probabilities that don’t align with this common three-sigma expression.

DGPS accuracy is described by a radius around the reported position that is expected to contain the true position with a certain probability. In many navigation applications, errors are treated as roughly Gaussian, so about 68% of errors fall within one standard deviation, 95% within two, and 99.7% within three. Saying the performance is 10 meters with 99.7% probability means the true position lies within 10 meters of the DGPS fix in 99.7% of cases—that’s a three-sigma bound. This is the standard way to express DGPS accuracy, pairing a distance with a high confidence level. Other options mix different distances and probabilities that don’t align with this common three-sigma expression.