Circular Error Probable (CEP) is the scatter radius with which the position accuracy ofnavigation devices
is specified. The CEP value is a probability value. It is
given as a percentage and refers to the radiusof
a circular area whose center is determined by the GPS system.measurement results are within this radius of 5 m, but also half of the measurement values
are outside. Furthermore, it is the case that 95 % of all measurement points are located in a circle with twice the radius, which would correspond to 10 m. The location accuracy of the CEP value can be improved by combining it with other navigation systems.