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  2. Horizon - Wikipedia

    en.wikipedia.org/wiki/Horizon

    View of the ocean with two ships: one in the foreground and one to the left of it on the horizon. Historically, the distance to the visible horizon has long been vital to survival and successful navigation, especially at sea, because it determined an observer's maximum range of vision and thus of communication, with all the obvious consequences for safety and the transmission of information ...

  3. Geostationary orbit - Wikipedia

    en.wikipedia.org/wiki/Geostationary_orbit

    where F g is the gravitational force acting between two objects, M E is the mass of the Earth, 5.9736 × 10 24 kg, m s is the mass of the satellite, r is the distance between the centers of their masses, and G is the gravitational constant, (6.674 28 ± 0.000 67) × 10 −11 m 3 kg −1 s −2.

  4. Geographical distance - Wikipedia

    en.wikipedia.org/wiki/Geographical_distance

    Geographical distance or geodetic distance is the distance measured along the surface of the Earth, or the shortest arch length. The formulae in this article calculate distances between points which are defined by geographical coordinates in terms of latitude and longitude. This distance is an element in solving the second (inverse) geodetic ...

  5. Earth-centered, Earth-fixed coordinate system - Wikipedia

    en.wikipedia.org/wiki/Earth-centered,_Earth...

    The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.

  6. Pseudorange - Wikipedia

    en.wikipedia.org/wiki/Pseudorange

    The accuracy of quartz clocks in general is worse (i.e. more) than one part in a million; thus, if the clock hasn't been corrected for a week, the deviation may be so great as to result in a reported location not on the Earth, but outside the Moon's orbit. Even if the clock is corrected, a second later the clock may no longer be usable for ...

  7. Satellite ground track - Wikipedia

    en.wikipedia.org/wiki/Satellite_ground_track

    A satellite ground track or satellite ground trace is the path on the surface of a planet directly below a satellite's trajectory. It is also known as a suborbital track or subsatellite track , and is the vertical projection of the satellite's orbit onto the surface of the Earth (or whatever body the satellite is orbiting). [ 1 ]

  8. Line-of-sight propagation - Wikipedia

    en.wikipedia.org/wiki/Line-of-sight_propagation

    Assuming a perfect sphere with no terrain irregularity, the distance to the horizon from a high altitude transmitter (i.e., line of sight) can readily be calculated. Let R be the radius of the Earth and h be the altitude of a telecommunication station. The line of sight distance d of this station is given by the Pythagorean theorem;

  9. Google Earth - Wikipedia

    en.wikipedia.org/wiki/Google_Earth

    Google Earth is a web and computer program that renders a 3D representation of Earth based primarily on satellite imagery.The program maps the Earth by superimposing satellite images, aerial photography, and GIS data onto a 3D globe, allowing users to see cities and landscapes from various angles.