circular error

circular error

[′sər·kyə·lər ′er·ər] (ordnance) A bombing error measured by the radial distance of a point of bomb impact, or mean point of impact, from the center of the target, excluding gross errors. With an airburst atomic bomb, the bombing error measured from the point on the ground immediately below the bomb burst to the desired ground zero.

circular error (CE)

An accuracy figure representing the stated percentage of probability that any point expressed as a function of two linear components (e.g., horizontal position) will be within the given figure. Circular error probability (CEP 50%), and CE (90%) are used commonly. A horizontal measurement on the ground, in feet or meters, defining a radius of a circle, within which an object of known coordinates should be found on an image. The CE value should have some measure of probability (P) associated with it. For example, a CE of 100 m and .9 P, means that 90% of the time the object will fall within a circle having a radius of 100 m. Circular error is normally used in armament delivery results.