Figure 2. Effects of horizontal refraction in the plane X and Y, rii and rik are assumed to be the refracted horizontal angle [1]

From

Improved Model of Refracted Horizontal Angle: Dependency on Zenith Angle

Mansoor Sabzali, Lloyd Pilgrim

American Journal of Civil Engineering and Architecture. 2023, 11(2), 38-44 doi:10.12691/ajcea-11-2-2