optical horizon

optical horizon

[′äp·tə·kəl hə′rīz·ən]
(geodesy)
Locus of points at which a straight line from the given point becomes tangential to the earth's surface.
References in periodicals archive ?
The research concerns the use of this recognition algorithm for the development of an optical horizon sensor.
The optical horizon sensor and magnetometer integration decreases the SINS vertical line analytical modelling errors [DELTA][[phi].sub.x], [DELTA][[phi].sub.y] and the meridian direction estimation error [[DELTA][phi].sub.z] respectively.
This is primarily a function of the curvature of the Earth, and is extended beyond the optical horizon (an average of about 15%) by atmospheric refraction.