Search results
Results from the WOW.Com Content Network
The size of a target's image on radar is measured by the radar cross section or RCS, often represented by the symbol σ and expressed in square meters. This does not equal geometric area. A perfectly conducting sphere of projected cross sectional area 1 m 2 (i.e. a diameter of 1.13 m) will have an RCS of 1 m 2. For radar wavelengths much less ...
In a radar image, one can see only the energy that was reflected back towards the radar antenna. The radar moves along a flight path and the area illuminated by the radar, or footprint, is moved along the surface in a swath, building the image as it does so. [1] Digital radar images are composed of many dots.
Optical cross section (OCS) is a value which describes the maximum amount of optical flux reflected back to the source. [1] The standard unit of measurement is m 2 /sr. OCS is dependent on the geometry and the reflectivity at a particular wavelength of an object. Optical cross section is useful in fields such as LIDAR.
An object that has multiple reflections from smooth surfaces produces a radar return of greater magnitude than might be expected from the physical size of the object. This effect was put to use on the ADM-20 Quail, a small decoy missile which had the same radar cross section as a B-52.
Inverse synthetic-aperture radar (ISAR) is a radar technique using radar imaging to generate a two-dimensional high resolution image of a target. It is analogous to conventional SAR , except that ISAR technology uses the movement of the target rather than the emitter to create the synthetic aperture . [ 1 ]
Vertical cross-section through a supercell showing the BWER. The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by higher reflectivities aloft, forming a kind of dome of weak echoes.
Radar scatterometers use radio or microwaves to determine the normalized radar cross section (σ 0, "sigma zero" or "sigma naught") of a surface. They are often mounted on weather satellites to find wind speed and direction, and are used in industries to analyze the roughness of surfaces.
Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. [1] SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars.