Search results
Results from the WOW.Com Content Network
The principle of operation behind RASS is as follows: Bragg scattering occurs when acoustic energy (i.e., sound) is transmitted into the vertical beam of a radar such that the wavelength of the acoustic signal matches the half-wavelength of the radar. As the frequency of the acoustic signal is varied, strongly enhanced scattering of the radar ...
"Bragg-Scattering". "Bragg scattering". esa. Gough, Jack (1993). Watching the skies: a history of ground radar for the air defence of the United Kingdom by the Royal Air Force from 1946 to 1975. HMSO. ISBN 978-0-11-772723-6. Ray, Thomas (June 1965). A History of the DEW Line 1964 - 1964 (PDF) (Technical report). Air Force Historical Research ...
The radar echo is generated by specular reflections from the sea surface. The low grazing angle mode. The radar echo is generated by Bragg scattering, hence wind generated surface ripple (capillary waves) must be present. The backscattered signal will be modulated by the large surface gravity waves and the gravity wave information is derived ...
The scattering mechanism is known as Bragg scattering, which occurs from the waves that are in resonance with the microwaves. The backscattered power depends on the wind speed and direction. Viewed from different azimuth angles, the observed backscatter from these waves varies.
The radar station with 18 military & 5 civilians was planned for transfer after the 1978 Base Realignment and Closure Commission. [7] After the station transferred to the FAA when Aerospace Defense Command was inactivated, the Air Force continued to operate the AN/FPS-90 height-finder by then modified to an AN/FPS-116 (removed c. 1988). [ 8 ]
This equation, Bragg's law, describes the condition on θ for constructive interference. [12] A map of the intensities of the scattered waves as a function of their angle is called a diffraction pattern. Strong intensities known as Bragg peaks are obtained in the diffraction pattern when the scattering angles satisfy Bragg condition.
Incoming light scatters (see Brillouin scattering) off the resulting periodic index modulation and interference occurs similar to Bragg diffraction. The interaction can be thought of as a three-wave mixing process resulting in sum-frequency generation or difference-frequency generation between phonons and photons .
The spacecraft will measure "radio aurora", or the Bragg scattering from FAI that are illuminated with a narrow beam incoherent scatter radar (ISR) on the ground. This remote sensing method is based on the powerful mathematical relation that the radio aurora intensity is proportional to the irregularity k-spectrum evaluated at the Bragg wave ...