Results 1 to 10 of about 482 (148)

A Modified Radiopropagation Multipath Model for Constant Refractivity Gradient Profiles [PDF]

Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2023
This paper presents a radiopropagation algorithm based on a Ray Tracing (RT) technique that combines a modified multipath model for constant refractivity gradient profiles and the Uniform Theory of Diffraction (UTD).
D. Parada, C. G. Rego, D. Guevara, A. Navarro, G. L. Ramos, R. Oliveira   +5 more
doaj   +1 more source

Global analysis of atmospheric refractivity profiles from COSMIC GPS radio occultation soundings [PDF]

Geodetski Vestnik, 2020
Atmospheric refractivity is a function of temperature, pressure and water vapor. The refractivity retrieved from the Global Navigation Satellite Systems (GNSS) radio occultation soundings has fine vertical resolution and high accuracy, so it can be used ...
Shaoqi Gong, Cunjie Zhang, Geshi Tang, Yehui Zhang, Jing Han   +4 more
doaj   +1 more source

Study of an Atmospheric Refractivity Estimation from a Clutter Using Genetic Algorithm

Applied Sciences, 2022
In this paper, a method for estimating atmospheric refractivity from sea and land clutters is proposed. To estimate the atmospheric refractivity, clutter power spectrums based on an artificial tri-linear model are calculated using an Advanced Refractive ...
Doyoung Jang, Jongmann Kim, Yong Bae Park, Hosung Choo   +3 more
doaj   +1 more source

Prediction of Wide Range Two-Dimensional Refractivity Using an IDW Interpolation Method from High-Altitude Refractivity Data of Multiple Meteorological Observatories

Applied Sciences, 2021
This article proposes a method for the prediction of wide range two-dimensional refractivity for synthetic aperture radar (SAR) applications, using an inverse distance weighted (IDW) interpolation of high-altitude radio refractivity data from multiple ...
Sungsik Wang, Tae Heung Lim, Kyoungsoo Oh, Chulhun Seo, Hosung Choo   +4 more
doaj   +1 more source

Tropospheric Refractivity Profile Estimation by GNSS Measurement at China Big-Triangle Points

Atmosphere, 2021
Atmospheric radio refractivity has an obvious influence on the signal transmission path and communication group delay effect. The uncertainty of water vapor distribution is the main reason for the large error of tropospheric refractive index modeling ...
Xiang Dong, Fang Sun, Qinglin Zhu, Leke Lin, Zhenwei Zhao, Chen Zhou   +5 more
doaj   +1 more source

Influence of weather variables on atmospheric refractivity over Auchi Town, Edo State, Nigeria

Journal of Applied Sciences and Environmental Management, 2018
In this study, atmospheric variables such as air temperature, relative humidity and atmospheric pressure were evaluated in order to determine the atmospheric refractivity over Auchi town in Edo State, Nigeria using a portable weather monitoring system ...
K.E. Ukhurebor, S.O. Azi, I.C. Abiodun, S.E. Ojiemudia   +3 more
doaj   +1 more source

Long-Term Characterization of Vertical Radio Refractivity Gradients and Tropospheric Propagation Conditions over North-Central Nigeria Using ERA5 Reanalysis Data [PDF]

Physics Access
This study presents a comprehensive long-term evaluation of vertical radio refractivity and refractivity gradients over selected locations in North-Central Nigeria.
Usman S Lami, Ikechiamaka N Florenc, Akinbolati Akinsanmi, Isaac H Daniel, Owolabi J Adeyemi, Abubakar Dalhat, Stephen C Nnochin, Akusu O Christiana, Mansur Bala, Bolorunduro C Blessing, Mohammed Mohammed, Adamu Idris   +11 more
doaj   +1 more source

Estimation and evaluation of COSMIC radio occultation excess phase using undifferenced measurements [PDF]

Atmospheric Measurement Techniques, 2017
In the GPS radio occultation technique, the atmospheric excess phase (AEP) can be used to derive the refractivity, which is an important quantity in numerical weather prediction.
P. Xia, S. Ye, K. Jiang, D. Chen
doaj   +1 more source

Development and evaluation of airborne microwave refractometer for studies on atmospheric tropical boundary layer radiorefractive index [PDF]

Annales Geophysicae, 1994
Observations of high-resolution data on radio refractivity were obtained by the airborne microwave refractometer over the Indian sub-continent (a tropical country) from 1971 to 1988. Detailed vertical and horizontal distributions of radio refractivity
S. B. S. S. Sarma, B. M. Reddy
doaj   +1 more source

High Temporal Resolution Refractivity Retrieval from Radar Phase Measurements

Remote Sensing, 2018
Knowledge of the spatial and temporal variability of near-surface water vapor is of great importance to successfully model reliable radio communications systems and forecast atmospheric phenomena such as convective initiation and boundary layer processes.
Rubén Nocelo López, Verónica Santalla del Río   +1 more
doaj   +1 more source