Circular error probability


CEP refers to the radius of a circle within which a stated percentage of measurements for a given point will fall. For example, if the horizontal accuracy of a surveyed point is stated as 1 m with 90% CEP, then 90% of measurements of this point will fall within a circle of radius 1 m. The true position is then estimated to lie at the centre of this circle.

Source: ICAO
Abbreviations: CEP