GPS Receivers with NMEA Output

GPS modules with NMEA output are available for less than 80 pounds, and compact hand-held GPS units with the interface are now hardly any more expensive. This article shows what can now be done with these units.The Global Positioning System (GPS) allows the user to determine very accurately his position in space. Since the artificial error introduced for civilian users has been switched off, the accuracy is now around 20 to 50 m, and in practice an error of rather less than 10 m can be achieved. Using Differential GPS (DGPS) the accuracy can be improved still further with the aid of correction information.