The U.S. Government is committed to providing GPS Tracking to the civilian community a “worst case” pseudorange accuracy of 7.8 meters at a 95% confidence level. The actual accuracy end users can expect depends on factors outside the government’s control, including atmospheric effects and receiver quality. Real-world data show that some high-quality GPS receivers currently attain better than 3 meter horizontal position accuracy.
Higher accuracy is available today by using GPS Tracking in combination with various augmentation systems. These enable real-time positioning to within a few centimeters, and post-processed positioning to within millimeters. The U.S. Government is committed to modernizing the GPS Tracking constellation to enable higher civilian accuracy without augmentations. The first of many next-generation GPS Tracking satellites was fielded in 2005.