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The azimuth is the angle between the north vector and the star's vector on the horizontal plane. [2] Azimuth is usually measured in degrees (°), in the positive range 0° to 360° or in the signed range -180° to +180°.
Even with these restrictions, if the polar angle (inclination) is 0° or 180°—elevation is −90° or +90°—then the azimuth angle is arbitrary; and if r is zero, both azimuth and polar angles are arbitrary. To define the coordinates as unique, the user can assert the convention that (in these cases) the arbitrary coordinates are set to zero.
Azimuth is measured eastward from the north point (sometimes from the south point) of the horizon; altitude is the angle above the horizon. The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles of a spherical coordinate system : altitude and azimuth .
In satellite broadcasting, a bearing is the combination of antenna azimuth and elevation required to point (aim) a satellite dish antenna in a given direction. The bearing for geostationary satellites is constant. The bearing for polar-orbiting satellites varies continuously.
At any range, with similar azimuth and elevation angles and as viewed by a radar with an unmodulated pulse, the range resolution is approximately equal in distance to half of the pulse duration times the speed of light (approximately 300 meters per microsecond). Radar echoes, showing a representation of the carrier
for β, the range covers π radians (but can not be said to be modulo π). For example, it could be [0, π ] or [− π /2, π /2] . The angles α , β and γ are uniquely determined except for the singular case that the xy and the XY planes are identical, i.e. when the z axis and the Z axis have the same or opposite directions.
The accuracy of Radar Set AN/FPS-16 is such that the position data obtained from point-source targets has azimuth and elevation angular errors of less than 0.1 milliradian (approximately 0.006 degree) and range errors of less than 5 yards (5 m) with a signal-to-noise ratio of 20 decibels or greater.
[1] The implication is that azimuth and/or elevation 'aiming' is done using instrumental methods. Hence indirect fire means applying 'firing data' to azimuth and elevation sights and laying these sights. Longer range uses a higher trajectory, and in theory maximum range is achieved with an elevation angle of 45 degrees. [2] [3] [4]