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See also Non-line-of-sight propagation for more on impairments in propagation. It is important to take into account the curvature of the Earth for calculation of line-of-sight paths from maps, when a direct visual fix cannot be made. Designs for microwave formerly used 4 ⁄ 3 Earth radius to compute clearances along the path.
An example of using a viewshed analysis on a line segment is from the Wyoming State Office, Bureau of Land Management, in which the office used a viewshed analysis to determine the visibility from National Historic Trails across Wyoming. Within the Rock Springs Field Office area there are five different viewsheds to choose from.
Line-of-sight fire, shooting directly at a visible target on a relatively flat trajectory. The target is in the line of sight of the sighting device and the rifleman's rule applies. Line-of-sight range; Line-of-sight (missile), the straight line between the missile and the target; Radar horizon
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
Sight is defined as the observation of the altitude, and sometimes also the azimuth, of a celestial body for a line of position; or the data obtained by such observation. [1] The mathematical basis of sight reduction is the circle of equal altitude. The calculation can be done by computer, or by hand via tabular methods and longhand methods.
The frequency of radio waves used by most radars, in the form of microwaves, travel in straight lines.This generally limits the detection range of radar systems to objects on their horizon (generally referred to as "line of sight" since the aircraft must be at least theoretically visible to a person at the location and elevation of the radar transmitter) due to the curvature of the Earth.
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A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...