Anomalous Propagation and Interference Fields
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Beyond-Line-Of-Sight Communications with Ducting Layer Ergin Dinc, Student Member, IEEE, Ozgur B
IEEE COMMUNICATIONS MAGAZINE 1 Beyond-Line-of-Sight Communications with Ducting Layer Ergin Dinc, Student Member, IEEE, Ozgur B. Akan, Senior Member, IEEE Abstract—Near-surface wave propagation at microwave fre- 8 :JR:`R IQ ].V`V quencies especially 2 GHz and above shows significant depen- dence on atmospheric ducts that are the layer in which rapid decrease in the refractive index occurs. The propagating signals in the atmospheric ducts are trapped between the ducting layer and the sea surface, so that the power of the propagating signals do not spread isotropically through the atmosphere. As a result, these signals have low path-loss and can travel over-the-horizon. V: Since atmospheric ducts are nearly permanent at maritime and coastal environments, ducting layer communication is a promis- 8 IQ ].V`1H%H ing method for beyond-Line-of-Sight (b-LoS) communications especially in naval communications. To this end, we overview %H 1J$:7V` the characteristics and the channel modeling approaches for the ducting layer communications by outlining possible open research areas. In addition, we review the possible utilization of the ducting layer in Network Centric Operations (NCO) to empower decision making for the b-LoS operations. V: Index Terms—Atmospheric ducts, ducting layer, refractivity, beyond-line-of-sight communications Fig. 1. Signal spreading in the standard atmosphere and the atmospheric duct. I. INTRODUCTION TMOSPHERIC ducts that are caused by rapid decrease Ducting layer studies mainly focus on refractivity estimation A in the refractive index of the lower atmosphere have techniques and radar path-loss calculations [1], [2]. However, tremendous effects on the near-surface wave propagation. -
Spheric Duct Interference in TD-LTE Networks
Journal of Communications and Information Networks, Vol.2, No.1, Mar. 2017 DOI: 10.1007/s41650-017-0006-x Research paper c Posts & Telecom Press and Springer Singapore 2017 Special Issue on Wireless Big Data Analysis and prediction of 100 km-scale atmo- spheric duct interference in TD-LTE networks Ting Zhou1,3, Tianyu Sun1,2,3, Honglin Hu3*, Hui Xu1,3, Yang Yang1,3, Ilkka Harjula4, Yevgeni Koucheryavy5 1. Key Lab of Wireless Sensor Network and Communication, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 201800, China 2. School of Information Science and Technology, ShanghaiTech University, Shanghai 201204, China 3. Shanghai Research Center for Wireless Communication, Shanghai 201204, China 4. VTT Technical Research Centre of Finland, VTT FI-02044, Finland 5. Tampere University of Technology, Korkeakoulunkatu 10, Tampere FI-33720, Finland * Corresponding author, email: [email protected] Abstract: Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere. Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther, i.e, hundreds of kilometers. In a large-scale deployed TD-LTE (Time Division Long Term Evolution) network, atmospheric ducts cause faraway downlink wireless signals to propagate beyond the designed protection distance and interfere with local uplink signals, thus resulting in a large outage probability. In this paper, we analyze the characteristics of ADI atmospheric duct interference (Atmospheric Duct Interference) by the use of real network-side big data from the current operated TD-LTE network owned by China Mobile. The analysis results yield the time varying and directional characteristics of ADI. -
Effects of Anomalous Propagation Conditions on Weather Radar Observations
13 Effects of Anomalous Propagation Conditions on Weather Radar Observations Joan Bech1, Adolfo Magaldi2, Bernat Codina1 and Jeroni Lorente1 1Dep. Astronomy and Meteorology, University of Barcelona 2Institute of Space Sciences, Spanish National Research Council (CSIC), Bellatera Spain 1. Introduction The effect of atmospheric propagation on radar observations is an important topic both for radar application developers and end-users of radar products, particularly of weather radar systems. An excellent review of this subject is given by Patterson (2008), and most general books about weather radars have a chapter on the topic –see for example Battan (1973), Collier (1996), Doviak and Zrnic (2006), Rinehart (2001) or Sauvageot (1991). In this chapter our objective is to provide an overview of the effects of anomalous propagation conditions on weather radar observations, based mostly on studies performed by the authors during the last decade, summarizing results from recent publications, presentations, or unpublished material. We believe this chapter may be useful as an introductory text for graduate students, or researchers and practitioners dealing with this topic. Throughout the text a spherical symmetric atmosphere is assumed and the focus is on the occurrence of ground and sea clutter and subsequent problems for weather radar applications. Other related topics such as long-path, over-the-horizon propagation and detection of radar targets (either clutter or weather systems) at long ranges is not considered here; however readers should be aware of the potential problems these phenomena may have as range aliasing may cause these echoes appear nearer than they are – for more details see the discussion about second trip echoes by Zrnic, this volume. -
Ducting and Turbulence Effects on Radio-Wave Propagation in An
Progress In Electromagnetics Research B, Vol. 60, 301–315, 2014 Ducting and Turbulence Effects on Radio-Wave Propagation in an Atmospheric Boundary Layer Yung-Hsiang Chou and Jean-Fu Kiang* Abstract—The split-step Fourier (SSF) algorithm is applied to simulate the propagation of radio waves in an atmospheric duct. The refractive-index fluctuation in the ducts is assumed to follow a two- dimensional Kolmogorov power spectrum, which is derived from its three-dimensional counterpart via the Wiener-Khinchin theorem. The measured profiles of temperature, humidity and wind speed in the Gulf area on April 28, 1996, are used to derive the average refractive index and the scaling parameters in order to estimate the outer scale and the structure constant of turbulence in the atmospheric boundary layer (ABL). Simulation results show significant turbulence effects above sea in daytime, under stable conditions, which are attributed to the presence of atmospheric ducts. Weak turbulence effects are observed over lands in daytime, under unstable conditions, in which the high surface temperature prevents the formation of ducts. 1. INTRODUCTION There are three basic types of atmospheric duct: Surface duct, surface-based duct and elevated duct. A surface duct is usually caused by a temperature inversion [1]. An evaporation duct is a special case of surface duct, which appears over water bodies accompanied by a rapid decrease of humidity with altitude [2]. Surface-based ducts are formed when the upper air is exceptionally warm and dry compared with that on the surface [2]. Elevated ducts usually appear in the trade-wind regions between the mid-ocean high-pressure cells and the equator [2]. -
Geophysical Aspects of Atmospheric Refraction
NRL Report 7725 Geophysical Aspects of Atmospheric Refraction CHARLES G. PURVES Aerospace Systems Branch Space Systems Division June 7, 1974 NAVAL RESEARCH LABORATORY Washington, D.C. Approved for public release; distribution unlimited. C= SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) C-` READ INSTRUCTIONS r- REPORTDOCUMENTATION PAGE BEFORE COMPLETING FORM ;11 I. REPORT NUMBER 2, GOVT ACCESSIONNO. 3. RECIPIENT'S CATALOG NUMBER 11 NRL Report 7725 -7 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED Final report on one phase of a r1r GEOPHYSICAL ASPECTS OF ATMOSPHERIC continuing NRL Problem. REFRACTION 6. PERFORMING ORG. REPORT NUMBER 7, AUTHOR(s) S. CONTRACT OR GRANT NUMBER(s) Charles G. Purves 9. PERFORMINGORGANIZATION NAME AND ADDRESS 10. PROGRAMELEMENT, PROJECT, TASK AREA & WORK UNIT NUMBERS Naval Research Laboratory NRL Problem R07-20 Washington, D.C. 20375 RE 12-151-402-4024 II.CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Department of the Navy June 7, 1974 Office of Naval Research 13. NUMBER OF PAGES Arlington, Va. 22217 44 14. MONITORING AGENCY NAME & ADDRESS(If different from Controlling Office) IS. SECURITY CLASS. (of this report) Unclassified ISa. DECLASSIFICATION/DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT (of this Report) Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (of the abstract enteredin Block 20, if different from Report) 18. SUPPLEMENTARY NOTES 19. KEY WORDS(Continue on reverse side if necessary and identify by block number) Anomalous radar propagation Electromagnetic waves Ray tracing Cloud correlations Haze layers Refractive index forecasts Cloud mosaic Microwave refractometer Refractive index profiles Convective cloud cells Radar horizon Satellite cloud photography Ducting gradients Radios (Continued) 20. -
A Bayesian Methodology for Detecting Anomalous Propagation in Radar Reflectivity Observations
The Centre for Australian Weather and Climate Research A partnership between the Bureau of Meteorology and CSIRO A Bayesian methodology for detecting anomalous propagation in radar reflectivity observations Justin R. Peter, Alan Seed, Peter Steinle, Susan Rennie and Mark Curtis CAWCR Technical Report No. 077 December 2014 A Bayesian methodology for detecting anomalous propagation in radar reflectivity observations Justin R. Peter, Alan Seed, Peter Steinle, Susan Rennie and Mark Curtis. The Centre for Australian Weather and Climate Research – a partnership between CSIRO and the Bureau of Meteorology CAWCR Technical Report No. 077 December 2014 ISSN: 1835-9884 Authors: Peter, J.R., Seed, A., Steinle, P., Rennie, S. and Curtis, M. Title: A Bayesian methodology for detecting anomalous propagation in radar reflectivity observations. ISBN: 978-1-4863-0473-8 (Electronic Resource PDF) Series: CAWCR technical report. Notes: Includes bibliographical references and index. Contact details Enquiries should be addressed to: Dr Justin R. Peter Centre for Australian Weather and Climate Research GPO Box 1289K Melbourne Vic 3001 Australia [email protected] Phone: +61 3 9669 4838 Copyright and disclaimer © 2014 CSIRO and the Bureau of Meteorology. To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO and the Bureau of Meteorology. CSIRO and the Bureau of Meteorology advise that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. -
Bibliography on Tropospheric Propagation of Radio Waves
National Bureau of Standards Library, M.W. Bldg APR 8 1965 ^ecknical ^iote 304 BIBLIOGRAPHY ON TROPOSPHERIC PROPAGATION OF RADIO WAVES WILHELM NUPEN mm U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS THE NATIONAL BUREAU OF STANDARDS The National Bureau of Standards is a principal focal point in the Federal Government for assuring maximum application of the physical and engineering sciences to the advancement of technology in industry and commerce. Its responsibilities include development and maintenance of the national stand- ards of measurement, and the provisions of means for making measurements consistent with those standards; determination of physical constants and properties of materials; development of methods for testing materials, mechanisms, and structures, and making such tests as may be necessary, particu- larly for government agencies; cooperation in the establishment of standard practices for incorpora- tion in codes and specifications; advisory service to government agencies on scientific and technical problems; invention and development of devices to serve special needs of the Government; assistance to industry, business, and consumers in the development and acceptance of commercial standards and simplified trade practice recommendations; administration of programs in cooperation with United States business groups and standards organizations for the development of international standards of practice; and maintenance of a clearinghouse for the collection and dissemination of scientific, tech- nical, and engineering information. The scope of the Bureau's activities is suggested in the following listing of its four Institutes and their organizational units. Institute for Basic Standards. Electricity. Metrology. Heat. Radiation Physics. Mechanics. Ap- plied Mathematics. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radio Stand- ards Laboratory: Radio Standards Physics; Radio Standards Engineering.** Office of Standard Ref- erence Data. -
Evaluation of Atmospheric Anomalous Propagation Conditions: an Application for Weather Radars
Evaluation of atmospheric anomalous propagation conditions: an application for weather radars J. Becha,c, D. Bebbingtonb, B. Codinac, A. Sairounic, J. Lorentec a Servei de Meteorologia de Catalunya, Dep. de Medi Ambient, Catalunya, Spain b Wave Propagation Research Group, Dep. Mathematics, Essex University, UK c Dep. d'Astronomia i Meteorologia, Universitat de Barcelona, Catalunya, Spain ABSTRACT Several meteorological conditions are known to cause anomalous propagation (AP) of microwave radiation. The effect of AP in weather radar measurements may be important as spurious echoes from distant ground targets may appear as precipitation leading to wrong rainfall estimations. AP may also affect dramatically the quality of clear air radar observations. In this study, more than one hundred radiosonde ascents are examined to evaluate the occurrence of AP at the coastal site of Barcelona (Spain). Temperature and humidity profiles are used to calculate refractivity gradients and to estimate the existence of ducting layers. Ducts represent the worst case of super refraction and within them microwaves travel trapped like in a waveguide. To detect thin AP features a vertical resolution higher than that given by standard operational radiosonde data is desirable. For this reason, radiosonde data recorded every 10 s have been used. Results are compared against standard operational radiosonde analysis revealing a significantly higher number of AP layers. The output of a mesoscale numerical weather prediction model is also used to derive refractivity gradients. The ability of the model to simulate the propagation conditions is overviewed in order to assess the feasibility of an operational diagnostic AP product. Keywords: anomalous propagation, subrefraction, ducting, weather radar, atmospheric refractivity, radar rainfall estimation, radiosonde, numerical weather prediction 1. -
Acronyms and Abbreviations
ACRONYMS AND ABBREVIATIONS AGL - Above Ground Level AP - Anomalous Propagation ARL -Above Radar Level AVSET - Automated Volume Scan Evaluation and Termination AWIPS - Advanced Weather Interactive Processing System BE – Book End as in Book End Vortex BWER - Bounded Weak Echo Region CAPE - Conditional Available Potential Energy CIN – Convective Inhibition CC – Correlation Coefficient Dual Pol Product CR -Composite Reflectivity Product CWA -County Warning Area DP – Dual Pol dBZ - Radar Reflectivity Factor DCAPE - Downdraft Conditional Available Potential Energy DCZ - Deep Convergence Zone EL – Equilibrium Level ET -Echo Tops Product ETC - Extratropical Cyclone FAR - False Alarm Ratio FFD – Forward Flank Downdraft FFG – Flash Flood Guidance GTG – Gate-To-Gate HP - High Precipitation supercell (storm) HDA -Hail Detection Algorithm LCL -Lifting Condensation Level LEWP -Line Echo Wave Pattern LP - Low Precipitation Supercell (storm) MARC - Mid Altitude Radial Convergence MCC - Mesoscale Convective Complex MCS - Mesoscale Convective System MCV – Mesoscale Convective Vortex MESO -Mesocyclone MEHS -Maximum Expected Hail Size OHP -One-Hour Rainfall Accumulation Product POSH -Probability of Severe Hail QLCS - Quasi Linear Convective Systems R - Rainfall Rate in Z-R relationship RF – Range Folding RFD - Rear Flank Downdraft RIJ - Rear Inflow Jet RIN – Rear Inflow Notch SAILS - Supplemental Adaptive Intra-Volume Low-Level Scan SCP – Supercell Composite Parameter SRH – Storm Relative Helicity SRM -Storm Relative Mean Radial Velocity STP –Significant -
Investigation of Anomalous Propagation Conditions in Central and West African Stations Using High-Resolution GPS Radiosonde Observations
J. Earth Syst. Sci. (2020) 129:220 Ó Indian Academy of Sciences https://doi.org/10.1007/s12040-020-01477-y (0123456789().,-volV)(0123456789().,-volV) Investigation of anomalous propagation conditions in Central and West African stations using high-resolution GPS radiosonde observations 1,6, 2 3,4 3 SAMUEL KAISSASSOU *, A LENOUO ,RSTANESSONG ,KAMSU TAMO , 3 3,5 6 AVONDOU ,WPOKAM and J KANKO 1Department of Electrical and Telecommunication Engineering, National Advanced School of Engineering, University of Yaounde 1, P.O. Box 8390, Yaounde, Cameroon. 2Department of Physics, Faculty of Science, University of Douala, P.O. Box 24157, Douala, Cameroon. 3LEMAP, Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon. 4Faculty of Agronomy and Agricultural Sciences, School of Wood, Water and Natural Resources, University of Dschang, P.O. Box 786, Ebolowa, Cameroon. 5Department of Physics, Higher Teacher’s Training College, University of Yaounde 1, P.O. Box 47, Yaounde, Cameroon. 6Department of Meteorology, Climatology, Hydrology and Soil Sciences, National Advanced School of Engineering, University of Maroua, P.O. Box 46, Maroua, Cameroon. *Corresponding author. e-mail: [email protected] MS received 13 December 2019; revised 23 May 2020; accepted 10 July 2020 A comprehensive study on the anomalous propagation (AP) conditions occurring over the central and west African stations was made from 2 years (January 2005–December 2006) high-resolution data measured by GPS (Global Positioning System) radio survey observations. Through data quality control and diagnostic analysis, the probability of AP occurrence and characteristic quantities of the three typical anomalous propagation conditions were given. -
Beyond-Line-Of-Sight Communications with Ducting Layer
DINC_LAYOUT_Layout 9/25/14 1:01 PM Page 37 MILITARY COMMUNICATIONS Beyond-Line-of-Sight Communications with Ducting Layer Ergin Dinc and Ozgur B. Akan ABSTRACT cussed later [1]. Experimental studies also show that atmospheric ducts are nearly permanent in Near-surface wave propagation at microwave the coastal and maritime environments due to frequencies, especially 2 GHz and above, shows high evaporation rates. As a result, the ducting significant dependence on atmospheric ducts layer communication becomes the dominant that are the layer in which rapid decrease in the propagation mechanism at the lower tropo- refractive index occurs. The propagating signals sphere, especially between 2 and 20 GHz. Since in the atmospheric ducts are trapped between the transmitter and receiver antennas should be the ducting layer and the sea surface, so that the located within the ducting layer and this mecha- power of the propagating signals do not spread nism is effective at the lower troposphere, naval isotropically through the atmosphere. As a result, communications can especially utilize b-LoS these signals have low path loss and can travel communications with the ducting layer. over the horizon. Since atmospheric ducts are Ducting layer studies mainly focus on refrac- nearly permanent in maritime and coastal envi- tivity estimation techniques and radar path loss ronments, ducting layer communication is a calculations [1, 2]. However, there are a few promising method for b-LoS communications studies that focus on the utilization of the atmo- especially in naval communications. To this end, spheric ducts as a communication medium. To we overview the characteristics and the channel this end, [3] provides a high-data-rate employ- modeling approaches for ducting layer commu- ment of the evaporation ducts for b-LoS sensor nications by outlining possible open research networks, where continuous satellite communi- areas. -
Estimation of Surface Duct Using Ground-Based GPS Phase Delay and Propagation Loss
remote sensing Article Estimation of Surface Duct Using Ground-Based GPS Phase Delay and Propagation Loss Qixiang Liao ID , Zheng Sheng *, Hanqing Shi, Jie Xiang and Hong Yu College of Meteorology and Oceanology, National University of Defense Technology, Nanjing 211101, China; [email protected] (Q.L.); [email protected] (H.S.); [email protected] (J.X.); [email protected] (H.Y.) * Correspondence: [email protected]; Tel.: +86-025-830-624 Received: 24 March 2018; Accepted: 7 May 2018; Published: 8 May 2018 Abstract: The propagation of Global Positioning System (GPS) signals at low-elevation angles is significantly affected by a surface duct. In this paper, we present an improved algorithm known as NSSAGA, in which simulated annealing (SA) is combined with the non-dominated sorting genetic algorithm II (NSGA-II). Matched-field processing was used to remotely sense the refractivity structure by using the data of ground-based GPS phase delay and propagation loss from multiple antenna heights. The performance was checked by simulation data with and without noise. In comparison with NSGA-II, the new hybrid algorithm retrieved the refractivity structure more efficiently under various noise conditions. We then modified the objective function and found that matched-field processing is more effective than the conventional least-squares method for inferring the refractivity parameters. Comparing the inversion results and in situ sounding data suggests that the improved method presented herein can capture refractivity characteristics in realistic environments. Keywords: surface duct; refractivity structure; GPS; remote sensing; NSGA-II; matched-field processing 1. Introduction An atmospheric duct is an atmospheric layer in which strong vertical gradients of refractivity determined by temperature and humidity affect the propagation of electromagnetic waves.