Wide-Band, Low-Frequency Pulse Profiles of 100 Radio Pulsars With
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Radio Astronomy
Theme 8: Beyond the Visible I: radio astronomy Until the turn of the 17th century, astronomical observations relied on the naked eye. For 250 years after this, although astronomical instrumentation made great strides, the radiation being detected was still essentially confined to visible light (Herschel discovered infrared radiation in 1800, and the advent of photography opened up the near ultraviolet, but these had little practical significance). This changed dramatically in the mid-20th century with the advent of radio astronomy. 8.1 Early work: Jansky and Reber The atmosphere is transparent to visible light, but opaque to many other wavelengths. The only other clear “window” of transparency lies in the radio region, between 1 mm and 30 m wavelength. One might expect that the astronomical community would deliberately plan to explore this region, but in fact radio astronomy was born almost accidentally, with little if any involvement of professional astronomers. Karl Jansky (1905−50) was a radio engineer at Bell Telephone. In 1932, while studying the cause of interference on the transatlantic radio-telephone link, he discovered that part of the interference had a periodicity of one sidereal day (23h 56m), and must therefore be coming from an extraterrestrial source. By considering the time at which the interference occurred, Jansky identified the source as the Milky Way. This interesting finding was completely ignored by professional astronomers, and was followed up only by the radio engineer and amateur astronomer Grote Reber (1911−2002). Reber built a modern-looking paraboloid antenna and constructed maps of the radio sky, which also failed to attract significant professional attention. -
Spectrum and the Technological Transformation of the Satellite Industry Prepared by Strand Consulting on Behalf of the Satellite Industry Association1
Spectrum & the Technological Transformation of the Satellite Industry Spectrum and the Technological Transformation of the Satellite Industry Prepared by Strand Consulting on behalf of the Satellite Industry Association1 1 AT&T, a member of SIA, does not necessarily endorse all conclusions of this study. Page 1 of 75 Spectrum & the Technological Transformation of the Satellite Industry 1. Table of Contents 1. Table of Contents ................................................................................................ 1 2. Executive Summary ............................................................................................. 4 2.1. What the satellite industry does for the U.S. today ............................................... 4 2.2. What the satellite industry offers going forward ................................................... 4 2.3. Innovation in the satellite industry ........................................................................ 5 3. Introduction ......................................................................................................... 7 3.1. Overview .................................................................................................................. 7 3.2. Spectrum Basics ...................................................................................................... 8 3.3. Satellite Industry Segments .................................................................................... 9 3.3.1. Satellite Communications .............................................................................. -
Airborne L-Band Radio Frequency Interference Observations from the SMAPVEX08 Campaign and Associated Flights James Park, Student Member, IEEE, J
This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 1 Airborne L-Band Radio Frequency Interference Observations From the SMAPVEX08 Campaign and Associated Flights James Park, Student Member, IEEE, J. T. Johnson, Fellow, IEEE, Ninoslav Majurec, Noppasin Niamsuwan, Member, IEEE, Jeffrey R. Piepmeier, Member, IEEE, Priscilla N. Mohammed, Member, IEEE, Christopher S. Ruf, Fellow, IEEE, Sidharth Misra, Simon H. Yueh, Fellow, IEEE, and Steve J. Dinardo, Member, IEEE Abstract—Statistics of radio frequency interference (RFI) ob- The current experience of significant RFI corruption of the served in the band 1398–1422 MHz during an airborne campaign observations of the SMOS radiometer [8], as well as the up- in the United States are reported for use in analysis and forecasting coming deployment of the Aquarius and SMAP missions [11], of L-band RFI for microwave radiometry. The observations were [12] motivate studies of the properties of the RFI environment conducted from September to October 2008, and included approx- imately 92 h of flight time, of which approximately 20 h of “tran- as well as the performance of a variety of RFI detection and sit” or dedicated RFI observing flights are used in compiling the mitigation approaches. statistics presented. The observations used include outbound and A recent work [7] has reported results from an airborne return flights from Colorado to Maryland, as well as RFI surveys L-band RFI observing system in Europe and Australia. The over large cities. The Passive Active L-Band Sensor (PALS) ra- hardware utilized in [7] was capable of implementing algo- diometer of NASA Jet Propulsion Laboratory augmented by three rithms for pulsed RFI detection using either a “pulse” or a dedicated RFI observing systems was used in these observations. -
A Layman's Interpretation Guide L-Band and C-Band Synthetic
A Layman’s Interpretation Guide to L-band and C-band Synthetic Aperture Radar data Version 2.0 15 November, 2018 Table of Contents 1 About this guide .................................................................................................................................... 2 2 Briefly about Synthetic Aperture Radar ......................................................................................... 2 2.1 The radar wavelength .................................................................................................................... 2 2.2 Polarisation ....................................................................................................................................... 3 2.3 Radar backscatter ........................................................................................................................... 3 2.3.1 Sigma-nought .................................................................................................................................................. 3 2.3.2 Gamma-nought ............................................................................................................................................... 3 2.4 Backscatter mechanisms .............................................................................................................. 4 2.4.1 Direct backscatter ......................................................................................................................................... 4 2.4.2 Forward scattering ...................................................................................................................................... -
Essential Radio Astronomy
February 2, 2016 Time: 09:25am chapter1.tex © Copyright, Princeton University Press. No part of this book may be distributed, posted, or reproduced in any form by digital or mechanical means without prior written permission of the publisher. 1 Introduction 1.1 AN INTRODUCTION TO RADIO ASTRONOMY 1.1.1 What Is Radio Astronomy? Radio astronomy is the study of natural radio emission from celestial sources. The range of radio frequencies or wavelengths is loosely defined by atmospheric opacity and by quantum noise in coherent amplifiers. Together they place the boundary be- tween radio and far-infrared astronomy at frequency ν ∼ 1 THz (1 THz ≡ 1012 Hz) or wavelength λ = c/ν ∼ 0.3 mm, where c ≈ 3 × 1010 cm s−1 is the vacuum speed of light. The Earth’s ionosphere sets a low-frequency limit to ground-based radio astronomy by reflecting extraterrestrial radio waves with frequencies below ν ∼ 10 MHz (λ ∼ 30 m), and the ionized interstellar medium of our own Galaxy absorbs extragalactic radio signals below ν ∼ 2 MHz. The radio band is very broad logarithmically: it spans the five decades between 10 MHz and 1 THz at the low-frequency end of the electromagnetic spectrum. Nearly everything emits radio waves at some level, via a wide variety of emission mechanisms. Few astronomical radio sources are obscured because radio waves can penetrate interstellar dust clouds and Compton-thick layers of neutral gas. Because only optical and radio observations can be made from the ground, pioneering radio astronomers had the first opportunity to explore a “parallel universe” containing unexpected new objects such as radio galaxies, quasars, and pulsars, plus very cold sources such as interstellar molecular clouds and the cosmic microwave background radiation from the big bang itself. -
DVB-SCENE Issue 21 Lo Res.Indd
Edition No.21 March 2007 DVB-SCENE Tune in to Digital Convergence Tune 21 The Standard for the Digital World I want This issue’s highlights > Convergence Utopia > IPTV Analysis & Update my > HDTV Update > Future Focus on DVB-T > DVB-H Interoperability > Introducing DVB-SH > A Look at Latin America > Market Watch IPTV Unique Broadband Systems Ltd. is the world’s leading designer and manufacturer of complete DVB-T/H system solutions for Mobile Media Operators and Broadcasters DVB-H IP Encapsulator DVB-T/H Gateway DVE 6000 DVE 7000 / DVE-R 7000 What makes DVE 6000 the best product on the market today? The DVE 7000 DVB-H Satellite Gateway is the core of highly optimized, efficient and cost effective mobile Dynamic Time SlicingTM Technique delivering DVB-H architecture. A single DVE 7000 device unprecedented bandwidth utilization and processes, distributes and manages global and local network efficiency (Statistical Multiplexing) content grouped in packages to multiple remote SFN DVB-SCENE : 02 Internal SI/PSI table editor, parser, compiler & MFN networks through a satellite link and drasti- and generator (UBS SI/PSI TDL) cally improves satellite link efficiency. The DVE-R 7000 Internal SFN Adapter satellite receiver demultiplexes the content specific to it’s location. Internal stream recorder and player IP DVB-S2 ASI Single compact unit DVE-R 7000 SFN1 DVE 6000 NetManager Application MODULATOR 1 SFN3 SFN2 MODULATOR 3 DVB-T/H Modulator MODULATOR 2 DVM 5000 Fully DVB-H Compliant 30 MHz to 1 GHz RF Output (L-band version available) Web Browser -
Mobile TV Technologies Zahid Ghadialy March 2006
Mobile TV Technologies Zahid Ghadialy March 2006 © 2006 Zahid Ghadialy What is Mobile TV Mobile TV Broadcasting allows the user to watch their favourite TV programs such as dramas, news, music, sports and documentaries on their mobile device. The service works by receiving a specialised digital TV broadcast signal from the air in much the same way as televisions at home will do in future. Channel guides will also be broadcast allowing users to keep abreast of the latest programs on air. It is not the same as a streaming video service over 3G or GPRS, but one which is optimised for longer period TV viewing by large numbers of simultaneous users with high picture quality and low battery power consumption. Mobile TV Technologies BCMCS: BroadCast MultiCast Services (3GPP2) DVB-H: Digital Video Braodcasting-Handheld (ETSI) ISDB-T: Integrated Service Digital Broadcasting – Terrestrial (ARIB) T-DMB: Terrestrial Digital Multimedia Broadcasting (Korean Standard) MediaFLO: Media Forward Link Only (Qualcomm proprietary) MBMS is not Mobile TV MBMS uses existing 3G Spectrum whereas Mobile TV needs new frequency spectrum Channel switching is faster using Mobile TV technologies compared to MBMS Very little number of channels using MBMS are possible as compared to Mobile TV technologies Battery life is much less if MBMS is used as compared to Mobile TV technologies Higher coverage possible with Mobile TV technologies Mobile TV Technologies In Depth Analysis Qualcomm has pulled together The FLO Forum, (Forward Link Only) which is pushing to standardize this Qualcomm’s technology for transmitting multimedia content to mobile devices. MediaFLO Qualcomm proprietary It uses unidirectional COFDM (Coded Orthogonal Frequency Division Multiplexing) Its under the process of standardisation Interested parties include LG, Sanyo, Sharp, Huawei In US, MediaFLO will deliver 29 channels on TV channel 55. -
An Elementary Approach Towards Satellite Communication
AN ELEMENTARY APPROACH TOWARDS SATELLITE COMMUNICATION Prof. Dr. Hari Krishnan GOPAKUMAR Prof. Dr. Ashok JAMMI AN ELEMENTARY APPROACH TOWARDS SATELLITE COMMUNICATION Prof. Dr. Hari Krishnan GOPAKUMAR Prof. Dr. Ashok JAMMI AN ELEMENTARY APPROACH TOWARDS SATELLITE COMMUNICATION WRITERS Prof. Dr. Hari Krishnan GOPAKUMAR Prof. Dr. Ashok JAMMI Güven Plus Group Consultancy Inc. Co. Publications: 06/2021 APRIL-2021 Publisher Certificate No: 36934 E-ISBN: 978-605-7594-89-1 Güven Plus Group Consultancy Inc. Co. Publications All kinds of publication rights of this scientific book belong to GÜVEN PLUS GROUP CONSULTANCY INC. CO. PUBLICATIONS. Without the written permission of the publisher, the whole or part of the book cannot be printed, broadcast, reproduced or distributed electronically, mechanically or by photocopying. The responsibility for all information and content in this Book, visuals, graphics, direct quotations and responsibility for ethics / institutional permission belongs to the respective authors. In case of any legal negativity, the institutions that support the preparation of the book, especially GÜVEN PLUS GROUP CONSULTANCY INC. CO. PUBLISHING, the institution (s) responsible for the editing and design of the book, and the book editors and other person (s) do not accept any “material and moral” liability and legal responsibility and cannot be taken under legal obligation. We reserve our rights in this respect as GÜVEN GROUP CONSULTANCY “PUBLISHING” INC. CO. in material and moral aspects. In any legal problem/situation TURKEY/ISTANBUL courts are authorized. This work, prepared and published by Güven Plus Group Consultancy Inc. Co., has ISO: 10002: 2014- 14001: 2004-9001: 2008-18001: 2007 certificates. This work is a branded work by the TPI “Turkish Patent Institute” with the registration number “Güven Plus Group Consultancy Inc. -
Potential of Different Optical and SAR Data in Forest and Land Cover Classification to Support REDD+ MRV
remote sensing Article Potential of Different Optical and SAR Data in Forest and Land Cover Classification to Support REDD+ MRV Laura Sirro 1,*, Tuomas Häme 1, Yrjö Rauste 1, Jorma Kilpi 1 ID , Jarno Hämäläinen 2, Katja Gunia 2, Bernardus de Jong 3 and Fernando Paz Pellat 4 1 VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, VTT FI-02044, Finland; tuomas.hame@vtt.fi (T.H.); yrjo.rauste@vtt.fi (Y.R.); jorma.kilpi@vtt.fi (J.K.) 2 Arbonaut Ltd., Kaislakatu 2, Joensuu FI-80130, Finland; [email protected] (J.H.); [email protected] (K.G.) 3 El Colegio de la Frontera Sur, Av. Rancho Polígono 2-A, Parque Industrial Lerma, Campeche, Campeche CP 24500, Mexico; [email protected] 4 Colegio de Postgraduados, Km 36.5 Carretera México-Texcoco, Texcoco 56230, Mexico; [email protected] * Correspondence: laura.sirro@vtt.fi; Tel.: +358-40-538-7769 Received: 9 May 2018; Accepted: 11 June 2018; Published: 14 June 2018 Abstract: The applicability of optical and synthetic aperture radar (SAR) data for land cover classification to support REDD+ (Reducing Emissions from Deforestation and Forest Degradation) MRV (measuring, reporting and verification) services was tested on a tropical to sub-tropical test site. The 100 km by 100 km test site was situated in the State of Chiapas in Mexico. Land cover classifications were computed using RapidEye and Landsat TM optical satellite images and ALOS PALSAR L-band and Envisat ASAR C-band images. Identical sample plot data from Kompsat-2 imagery of one-metre spatial resolution were used for the accuracy assessment. -
Great Discoveries Made by Radio Astronomers During the Last Six Decades and Key Questions Today
17_SWARUP (G-L)chiuso_074-092.QXD_Layout 1 01/08/11 10:06 Pagina 74 The Scientific Legacy of the 20th Century Pontifical Academy of Sciences, Acta 21, Vatican City 2011 www.pas.va/content/dam/accademia/pdf/acta21/acta21-swarup.pdf Great Discoveries Made by Radio Astronomers During the Last Six Decades and Key Questions Today Govind Swarup 1. Introduction An important window to the Universe was opened in 1933 when Karl Jansky discovered serendipitously at the Bell Telephone Laboratories that radio waves were being emitted towards the direction of our Galaxy [1]. Jansky could not pursue investigations concerning this discovery, as the Lab- oratory was devoted to work primarily in the field of communications. This discovery was also not followed by any astronomical institute, although a few astronomers did make proposals. However, a young electronics engi- neer, Grote Reber, after reading Jansky’s papers, decided to build an inno- vative parabolic dish of 30 ft. diameter in his backyard in 1935 and made the first radio map of the Galaxy in 1940 [2]. The rapid developments of radars during World War II led to the dis- covery of radio waves from the Sun by Hey in 1942 at metre wavelengths in UK and independently by Southworth in 1942 at cm wavelengths in USA. Due to the secrecy of the radar equipment during the War, those re- sults were published by Southworth only in 1945 [3] and by Hey in 1946 [4]. Reber reported detection of radio waves from the Sun in 1944 [5]. These results were noted by several groups soon after the War and led to intensive developments in the new field of radio astronomy. -
University of Groningen the Logistic Design of the LOFAR Radio Telescope Schakel, L.P
University of Groningen The logistic design of the LOFAR radio telescope Schakel, L.P. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2009 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Schakel, L. P. (2009). The logistic design of the LOFAR radio telescope: an operations Research Approach to optimize imaging performance and construction costs. PrintPartners Ipskamp B.V., Enschede, The Netherlands. Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 26-09-2021 Chapter 2 Radio Telescopes 2.1 Introduction This chapter explains the basics of radio telescopes, the types of radio telescopes that exist, and what they can observe in the universe. It is included to provide the reader background information on radio telescopes and to introduce concepts which will be used in later chapters. -
Mobile Tv: a Technical and Economic Comparison Of
MOBILE TV: A TECHNICAL AND ECONOMIC COMPARISON OF BROADCAST, MULTICAST AND UNICAST ALTERNATIVES AND THE IMPLICATIONS FOR CABLE Michael Eagles, UPC Broadband Tim Burke, Liberty Global Inc. Abstract We provide a toolkit for the MSO to assess the technical options and the economics of each. The growth of mobile user terminals suitable for multi-media consumption, combined Mobile TV is not a "one-size-fits-all" with emerging mobile multi-media applications opportunity; the implications for cable depend on and the increasing capacities of wireless several factors including regional and regulatory technology, provide a case for understanding variations and the competitive situation. facilities-based mobile broadcast, multicast and unicast technologies as a complement to fixed In this paper, we consider the drivers for mobile line broadcast video. TV, compare the mobile TV alternatives and assess the mobile TV business model. In developing a view of mobile TV as a compliment to cable broadcast video; this paper EVALUATING THE DRIVERS FOR MOBILE considers the drivers for future facilities-based TV mobile TV technology, alternative mobile TV distribution platforms, and, compares the Technology drivers for adoption of facilities- economics for the delivery of mobile TV based mobile TV that will be considered include: services. Innovation in mobile TV user terminals - the We develop a taxonomy to compare the feature evolution and growth in mobile TV alternatives, and explore broadcast technologies user terminals, availability of chipsets and such as DVB-H, DVH-SH and MediaFLO, handsets, and compression algorithms, multicast technologies such as out-of-band and Availability of spectrum - the state of mobile in-band MBMS, and unicast or streaming broadcast standardization, licensing and platforms.