  This paper presents the exact error analysis of point positioning equation
used for airborne three-dimensional(3D) imaging sensor. With differential
calculus and principles of precision analysis a mathematics formula on the
point position error and relative factors is derived to show how each error
source affects both vertical and horizontal coordinates. A comprehensive
analysis of the related error sources and their achievable accuracy are
provided. At last, two example figures are shown to compare the position
accuracy of elliptical trace scan and the line-trace scan are drawn under the
same error source and some corresponding conclusions.
