Circular error probable

Circular Error Probable (CEP) is a statistical measure used primarily in the fields of missile guidance, military targeting, and other applications involving precision and accuracy of targeting systems. It defines the radius of a circle, centered on the intended target, within which a specified percentage of impacts are expected to fall. In more precise terms, CEP is the radius of the smallest circle that encloses a certain percentage (commonly 50%) of the possible impact points from a given launch.