Results 271 to 280 of about 789,573 (302)
Some of the next articles are maybe not open access.
Remote sensing of radio refractivity by lidar
Tenth International Conference on Antennas and Propagation (ICAP), 1997Deterministic modelling of tropospheric radio propagation and exploitation of variations of microwave radar propagation require high quality, high resolution refractivity profiles in the first 1-2 km above the Earth's surface. Currently, routine measurements of refractivity are based on radiosonde measurements (via in-situ measurement of temperature ...
openaire +1 more source
Ionospheric refraction in radio source observations at long radio wavelengths
Journal of Astrophysics and Astronomy, 1984Ionospheric refraction effects encountered in radio source observations in the 30 to 75 MHz range with the Clark Lake TPT telescope are discussed. It is found that simple calibration procedures are sufficient to provide positions of unknown sources with an accuracy of approximately one arcmin.
openaire +1 more source
Predicting Radio Refractivity Using a Stochastic Model
2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014The radio refractivity of the atmosphere is a very important variable in radio communication. This paper attempts to model the radio refractivity over a tropical station (Akure, Southwestern Nigeria) with the aim of predicting future values. Atmospheric variables (temperature, pressure and relative humidity) were obtained over a period of eighteen ...
Joseph Sunday Ojo +2 more
exaly +2 more sources
A Tethered Psychrosonde for Radio Refractivity Profile Measurements
IETE Journal of Research, 1982The Indian sub-continent is subject to a varied and complex pattern of anomalous propagation conditions. These have a direct and significant influence on the performance of radar and microwave equipment.This paper describes the instruments and a recoverable Kytoon facility, developed for the first time in India to measure the gradient of temperature ...
S.P. Venkiteshwaran +3 more
openaire +1 more source
The Use of Radio Stars to Study Irregular Refraction of Radio Waves in the Ionosphere
Proceedings of the IRE, 1958The observations and the theory of radio star scintillation are reviewed, and the following conclusions are reached. 1) The frequency variation of amplitude and phase scintillations agrees with theory. 2) All observers agree that there is a marked increase of amplitude scintillation with increase in zenith angle.
openaire +1 more source
Ionospheric refraction effects on radio interferometer phase
Journal of Astrophysics and Astronomy, 1987The refraction of radio waves as they traverse through the terrestrial ionosphere and troposphere introduces a differential phase path which results for a radio interferometer in variations of the visibility phase. Though refraction due to troposphere is significant for synthesis radio telescopes operating at 1.0 GHz and above, ionospheric refraction ...
openaire +1 more source
A Comparison of Radar and Radio Interferometer Refraction Errors
IEEE Transactions on Aerospace and Electronic Systems, 1969The refraction error ? in measurements made with the simple interferometer is found to be similar in nature to the refraction error ? in the conventional radar measurement. For elevation angles ? > 10°, ? - ? > 0.05 mrad, when ? is computed after correcting for refraction along the interferometer extrapath S3.
openaire +1 more source
Refraction of radio waves in a plasma. Simplest case
1993Astonishingly enough, the foundations of the theory of radio wave propagation in an ionospheric plasma were laid long before the existence of an ionosphere was known and even before the electron was discovered, not to speak of plasma theory as such.
openaire +1 more source
Optical and Radio Refraction on Venus
Journal of the Atmospheric Sciences, 1968openaire +1 more source