A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Some Results of Estimating Refractive Properties of the Troposphere with the use of Radio Emission from Geostationary Satellites
Measurement techniques and equipment are described,, as well as the results measured for maritime and land propagation paths. Refractive properties of the troposphere were estimated, using radio emissions from the Asiasat 3S geostationary satellite. The measurement errors are analyzed. The uncertainties due to equipment have been minimized through a wise implementation of the interferometer principle. As was found in the course of the work, the principal errors of estimating refractive properties of the ionosphere result from quasiperiodic variations of the satellite position which are associated with the effects of the Sun and the Moon. Such errors can be minimized by involving the data on the satellite position obtained from the Internet. The results of the refractive measurements are compared with the data obtained from direct estimates of the near-surface index of refraction.
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Experimental Researches of Inhomogeneous Path Influence on Azimuth Errors of Bearing
The results of experimental researches of azimuth errors of bearing over the land, caused by turbulent troposphere and rough surface, are discussed. It is shown, that for a case when the elevation is commensurable with the receiving antenna pattern, the errors of bearing are determined, in general, by rough surface.
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Experimental Study into the UHF-Wave Attenuation Factor in the World Ocean Regions
Almost each sea-going vessel is known to be equipped with navigation, communication and other radio engineering facilities that serve to secure the safety of navigation and are chiefly operated at UHF-wave band. In developing these systems and calculating the energy potential for a necessary range one should be well aware of the radio signal attenuation processes on a propagation path. The key parameter of this path is the (radio) wave attenuation factor and its distance dependence V(r). A diversity of meteofactors influencing the radio signal attenuation over the oceanic expanses and the lack of experimental data could be routinely acquired were the compelling reasons why the researchers of the Institute for Radiophysics and Electronics, NASU, had spent many years on comprehensive radiophysical investigations carried out in different regions of the Atlantic, Indian, Arctic and Pacific Oceans.
Principles of Construction of Broad-Range Direct Computational Frequency Synthesizers
Development of a System for Guaranteed User Access to the ATM Network
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkiv 61085, Ukraine
Interpretation of Georadar Subsurface Probing Results in Terms of Absence of the a Priori Data
The method allowing to improve reliability of interpretation of subsurface probing results at solving the problems of the engineering geology based on the use of numerical method for solving of the Maxwell equations for the electromagnetic field in a bounded space by the finite elements method within a frequency domain in a combination with the data received from the georadar is presented.
V. Karazin National University of Kharkiv,
4, Svoboda Sq., Kharkiv, 61077, Ukraine
Application of Synthetic-Aperture Radar (SAR) Data in Tackling the Problems of Land Inventory, Diagnosis of Crops Condition, Gullying Processes and Hydrology