1. Recreational grade GPS receivers are sold at most box stores and at many sporting goods and camping stores. They are also available widely through Internet retailers. These units are the least expensive grade and are generally accurate to within +/- 25 feet (7.6 meters). These receivers run in the $100 to $600 range and are the type most often purchased by the general public.
2. Mapping grade GPS receivers are generally sold by “high end” and licensed resellers. These …
Every time a GPS receiver calculates its position, there is some amount of error inherent in the calculated position. Errors can be introduced from a number of sources (e.g., GPS clock errors, atmospheric conditions, the distribution of GPS satellites) over which the GPS user has little control.
Differential correction is a commonly used technique to reduce the systematic errors that decrease the accuracy of GPS positions. All differential correction techniques use correction data from a GPS base station to improve …
