standard positioning service (GPS) (SPS)

The U.S. satellite navigation system( GPS) has several services that differ in the resolution of location accuracy.

The GPS service for civilian use is the Standard Positioning Service (SPS), and the one for military use is the Precision Positioning Service( PPS). This SPS service can be used by the general public free of charge and has a positional accuracy of +/-15 m. It uses the C/A (coarse/acquisition) code.

For the SPS service, the root mean square value for position accuracy, the Distance Root Mean Square( drms), states that 95% of all measurements have a position accuracy of better than 100m. In addition, the PLC service specifications specify an error of `10^-4`, which exceeds the error rate for some applications.