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Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. [1] An object reflects a limited amount of radar energy back to the source. The factors that influence this include: [1] the material with which the target is made;
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Fluctuation loss is an effect seen in radar systems as the target object moves or changes its orientation relative to the radar system. It was extensively studied during the 1950s by Peter Swerling, who introduced the Swerling models to allow the effect to be simulated.
An object at height h above the ground and slant range R forms an angle α that can be calculated through sin α = h / R.By re-arrangement, R = h / sin α, or R = h csc α. The radar equation states that the signal received from an object, P e, varies inversely with the 4th power of range and directly as the square of the antenna gain, G, such that P e ~ G 2 / R 4.
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.
STC addresses this problem by implementing a reverse gain curve with the same characteristics as the radar equation, that is, a / dependency or some function close to that (often there are discrete steps). This dramatically damps down amplification of signals received shortly after the detection pulse is sent, preventing them from saturating ...
In the past, radar AGC was electronically controlled and affected the gain of the entire radar receiver. As radars evolved, AGC became computer-software controlled and affected the gain with greater granularity in specific detection cells. Radar multipath echoes from a target cause ghosts to appear.