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Backscattering Cross Section
Backscattering cross section is a property of an object that determines what proportion of incident wave energy is scattered from the object, back in the direction of the incident wave. It is defined as the area which intercepts an amount of power in the incident beam which, if radiated isotropically, would yield a reflected signal strength at the transmitter of the same magnitude as the actual object produces.Stout, G. E., & Mueller, E. A. (1968). Survey of relationships between rainfall rate and radar reflectivity in the measurement of precipitation. Journal of Applied Meteorology, 7(3), 465-474. See also * Radar cross-section * Target strength The target strength or '' acoustic size'' is a measure of the area of a sonar target. This is usually quantified as a number of decibels. For fish such as salmon, the target size varies with the length of the fish and a 5 cm fish could have a t ... References {{reflist Radar theory Radiation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotropic Radiation
Isotropic radiation is radiation that has the same intensity regardless of the direction of measurement, such as would be found in a thermal cavity. The radiation may be electromagnetic, sound or may be composed of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include electrons, the fundamental fermions ( quarks, leptons, an ...s. Radiation {{Physics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Cross-section
Radar cross-section (RCS), 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. An object reflects a limited amount of radar energy back to the source. The factors that influence this include: *the material with which the target is made; *the size of the target relative to the wavelength of the illuminating radar signal; *the absolute size of the target; *the incident angle (angle at which the radar beam hits a particular portion of the target, which depends upon the shape of the target and its orientation to the radar source); *the reflected angle (angle at which the reflected beam leaves the part of the target hit; it depends upon incident angle); *the polarization of the transmitted and the received radiation with respect to the orientation of the target. While important in detecting targets, strength of emitter and distance are not factors that affect the calculation of an RCS becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Target Strength
The target strength or '' acoustic size'' is a measure of the area of a sonar target. This is usually quantified as a number of decibels. For fish such as salmon, the target size varies with the length of the fish and a 5 cm fish could have a target strength of about -50 dB. Target strength (TS) is equal to 10 log10(''σ''bs/(1 m2)) dB, where ''σ''bs is the differential backscattering cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Abs .... Backscattering cross section is 4π''σ''bs. References Further reading "Introduction to the use of sonar systems for estimating fish biomass, FAO Fisheries Technical Paper No. 191, Revision 1, FAO 1982"''Fisheries Acoustics''Simmonds, E John and MacLennan, David N (2005) Blackwell Publishing. * C. S. Clay & H. Medwin, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Theory
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. The t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
