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The dipole antenna of a radar altimeter of 1947. A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft.
And for the same examples : the radar horizon for the radar at a 1-mile (1.6 km) altitude will be 102-mile (164 km) and the one at 75 feet (23 m) will be 12-mile (19 km). Furthermore, layers with an inverse trend of temperature or humidity cause atmospheric ducting , which bends the beam downward or even traps radio waves so that they do not ...
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. Pulse width also determines ...
The frequency of radio waves used by most radars, in the form of microwaves, propagate 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.
HGR-105 Radar surveillance; HK-JM long range meter-wave stealth detection 2-D surveillance radar; ... YLC-18 Radar medium-range low-altitude 3D radar;
The slant range (1) is the hypotenuse of the triangle represented by the altitude of the aircraft and the distance between the radar antenna and the aircraft's ground track (point (3) on the earth directly below the aircraft). In the absence of altitude information, for example from a height finder, the aircraft location would be plotted ...
A height finder radar is a type of 2-dimensional radar that measures altitude of a target.. The operator slews the antenna toward a desired bearing, identifies a target echo at a desired range on the range height indicator display, then bisects the target with a cursor that is scaled to indicate the approximate altitude of the target. [7]
Its range was 25–35 km with an accuracy of ±10–20 meters, azimuth 0.1 degrees, and elevation ±0.3-0.5 degrees. Only 51 units were produced before being superseded by the ‘Mannheim’. FuMG 64 Mannheim The Mannheim was an advanced development from the ‘Mainz’. It also had a 3-meter reflector, which was now made from a lattice ...