DGPS accuracy is typically within how many meters and with what probability?

DGPS accuracy is typically within how many meters and with what probability?

• A. 5 meters with 95% probability
• B. 10 meters with 99.7% probability
• C. 15 meters with 90% probability
• D. 20 meters with 99% probability

Answer: (B)

DGPS works by using a fixed ground reference station to compute the errors in the GPS pseudorange measurements and then broadcast corrections to your receiver. Applying these corrections reduces the range errors, tightening the overall position error distribution. In typical maritime DGPS service, you can expect around ten meters of horizontal accuracy with a 99.7 percent probability. Put another way, about 99.7 percent of fixes should fall within roughly ±10 meters of the true position, which aligns with a three-sigma bound if the errors are roughly normal. Real-world factors like distance from the reference station, multipath, and ionospheric conditions can affect the exact performance, but ten meters at 99.7 percent is the standard convention.

DGPS works by using a fixed ground reference station to compute the errors in the GPS pseudorange measurements and then broadcast corrections to your receiver. Applying these corrections reduces the range errors, tightening the overall position error distribution. In typical maritime DGPS service, you can expect around ten meters of horizontal accuracy with a 99.7 percent probability. Put another way, about 99.7 percent of fixes should fall within roughly ±10 meters of the true position, which aligns with a three-sigma bound if the errors are roughly normal. Real-world factors like distance from the reference station, multipath, and ionospheric conditions can affect the exact performance, but ten meters at 99.7 percent is the standard convention.