DOCSLIB.ORG

Optical Satellite Communication Toward the Future of Ultra High

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Optical Satellite Communication Toward the Future of Ultra High No.466 OCT 2017 Optical Satellite Communication toward the Future of Ultra High-speed Wireless Communications No.466 OCT 2017 National Institute of Information and Communications Technology CONTENTS FEATURE Optical Satellite Communication toward the Future of Ultra High-speed Wireless Communications 1 INTERVIEW New Possibilities Demonstrated by Micro-satellites Morio TOYOSHIMA 4 A Deep-space Optical Communication and Ranging Application Single photon detector and receiver for observation of space debris Hiroo KUNIMORI 6 Environmental-data Collection System for Satellite-to-Ground Optical Communications Verification of the site diversity effect Kenji SUZUKI 8 Optical Observation System for Satellites Using Optical Telescopes Supporting safe satellite operation and satellite communication experiment Tetsuharu FUSE 10 Development of "HICALI" Ultra-high-speed optical satellite communication between a geosynchronous satellite and the ground Toshihiro KUBO-OKA TOPICS 12 NICT Intellectual Property -Series 6- Live Electrooptic Imaging (LEI) Camera —Real-time visual comprehension of invisible electromagnetic waves— 13 Awards 13 Development of the “STARDUST” Cyber-attack Enticement Platform Cover photo Optical telescope with 1 m primary mirror. It receives data by collecting light from sat- ellites. This was the main telescope used in experiments with the Small Optical TrAn- sponder (SOTA). This optical telescope has three focal planes, a Cassegrain, a Nasmyth, and a coudé. The photo in the upper left of this page shows SOTA mounted in a 50 kg-class micro- satellite. In a world-leading effort, this was developed to conduct basic research on technology for 1.5-micron band optical communication between low-earth-orbit sat- ellite and the ground and to test satellite-mounted equipment in a space environment. Recent basic experiments in quantum communication have also been successful, as published in Nature Photonics. The telescope has a diameter of approximately 5 cm, and the mass of SOTA is approximately 6 kg. Optical Satellite Communication toward the Future of Ultra High-speed Wireless Communications Interview New Possibilities Demonstrated by Micro-satellites High precision Earth observation satel- Relay System (JDRS) using an optical data re- lites are being launched, one after another. lay satellite. These are micro-satellites of many types, used for research, education, and commer- ─How is research organized and what are cial purposes. As the development of space the main research themes in the Space Com- becomes more familiar in our daily lives, it munications Laboratory? is bringing a range of new conveniences. The Space Communications Laboratory, TOYOSHIMA: The laboratory has two locations, Wireless Networks Research Center, con- our headquarters in Koganei and the Kashima ducts R&D, focusing on optical (laser) sat- Space Technology Center, with approximately ellite communications, in hopes of making 50 members conducting research and devel- breakthroughs in satellite communications opment, including researchers, students, and data transmission technology. We spoke to supporting staff. Our two main research themes Laboratory Director, Dr. Morio TOYOSHIMA, are radio satellite communications and optical about this research. satellite communications. Our objectives are to establish satellite communications using these to develop communication networks that can be ■ "Mega-constellations" advancing in used at sea and in space, and be useful in mo- Morio TOYOSHIMA many countries Director bile situations and for disaster prevention and Space Communications Laboratory ─ To begin with, can you tell us about cur- mitigation. Wireless Networks Research Center rent trends in space communications tech- In several countries, recently so-called Joined the Communications Research Lab- nology? High-Throughput Satellite (HTS) services are oratory, Ministry of Posts and Telecommu- being started using Ka band communications nications (currently NICT), in 1994. After engaging in ETS-VI laser communication TOYOSHIMA: Many countries have been work- satellites with capacity exceeding 100 Gbps. experiments, Morio TOYOSHIMA was trans- ing actively on mega-constellation projects* in However, HTS services are limited by the com- ferred to NASDA (currently JAXA), and after recent years. This development of space itself munications capacity of gateways called feed- doing research at Vienna University of Tech- nology, worked on the research and devel- holds potential for innovation, and several of er links, connecting the earth station and the opment of onboard laser communication these projects are considering use of optical sat- satellite, that bundle user lines with terrestrial equipment for OICETS, SOTA, and HICALI, ellite communications. communications, and technology to expand the was involved in satellite laser communica- tion and quantum key distribution (QKD) A recent trend particularly in optical satel- feeder link communications capacity is highly experiments. Ph. D (Engineering). lite communications is the planned implemen- sought after. Our laboratory is conducting R&D tation of optical data relay satellite systems in on genuine multi-gigabit optical satellite com- the United States, Europe, and Japan. NASA's munications technology to resolve this issue Lunar Laser Communication Demonstration and establish infrastructure technologies for 10 (LLCD) at the Goddard Space Flight Center Gbps-class optical communications to resolve (GSFC) successfully established 622 Mbps op- demand for high-capacity next generation com- tical communication links between the moon munications. and the earth using a satellite launched in September 2013. And in April 2019, NASA's ■ Extra success achieved by the SOTA Laser Communication Relay Demonstration project (LCRD) project plans to launch an optical data relay satellite system into geostationary orbits. ─ Is the Small Optical TrAnsponder In Europe, the European Space Agency (ESA) (SOTA) project completed at the end of last operates an optical data relay service on geosta- year part of these efforts? tionary satellites called the European Data Re- lay System (EDRS), and the Copernicus Earth ＊ Groups of many small satellites or unmanned aircraft are observation project has launched five low-earth linked and cooperate to achieve a specific objective. As orbit (LEO) Sentinel satellites that initiate op- with constellations of stars and orbital positions, groups of satellites in particular are called satellite constellations. tical communications for data transmission. In There are many projects, largely promoted by Google (USA) Japan, the Japan Aerospace Exploration Agen- and Facebook (USA), being executed by companies includ- ing Space-X (USA), Oneweb (USA), O3b (UK), Leosat (USA), cy (JAXA) is also planning the Japanese Data and Kaskilo (formerly eightyLEO, Germany). NICT NEWS OCT 2017 1 Optical Satellite Communication toward the Future of Ultra High-speed Wireless Communications Interview New Possibilities Demonstrated by Micro-satellites TOYOSHIMA: The goal of the SOTA project was to expand optical satellite communications technology for very small satellites, developing 6 kg-class ultra-compact optical communica- tions equipment (Small Optical TrAnsponder, SOTA), and to demonstrate it mounted on the 50 kg-class Space Optical Communications Research Advanced Technology Satellite (SOCRATES). It was done in collaboration with private enterprise. The project started in 2009, and after the preliminary design review and the critical design review, a flight model was built. The SOCRATES satellite carrying SOTA was launched into low-earth orbit in May 2014. In the demonstration, images taken by an onboard camera mounted on the 50-kg class micro-sat- ellite were transmitted via optical communica- tions for the first time, using 1.5-micron laser light with original error correcting codes im- plemented in SOTA. The low-earth orbit made it accessible from various countries during its orbit, therefore international collaboration tests using SOTA were also conducted, involving international space agencies such as CNES in France, DLR in Germany, CSA in Canada, and the ESA in Europe. In particular, we conducted successful adaptive optics (AO) experiments SOTA installed in a micro-satellite. Telescope diameter is approximately 5 cm, using SOTA with the CNES optical ground and the mass is approximately 6 kg. station. In optical satellite communications ex- periments, telescope operation and commu- nication tests were done mainly by Expert Maki AKIOKA, Senior Researcher Yoshisada international collaboration experiments. This the low mass and resultant low inertial moment KOYAMA, Researcher Yasushi MUNEMASA, work yielded more success than expected. make it difficult to stabilize. No one had done and Researcher Hideki TAKENAKA. In- such a test and there was no past data, so there ternational collaborative experiments were ─ Can you tell us about some of the diffi- was an element of trial-and-error in the design planned and performed by Researcher Dimitar culties and innovations encountered in the work. KOLEV, and polarized light measurement ex- SOTA project? We also had issues with materials. In space, periments were done by Researcher Alberto thermally-resistant materials are an important CARRASCO-CASADO, and Researcher TOYOSHIMA: Earlier successes used satellites factor. Any deformation can result in inabil- Hideki TAKENAKA. as large as several hundred kilograms, so at ity to communicate properly. In space, metals These experiments
Load more

Recommended publications
  • SYLLABUS Optical Fiber Communication
    Optical Fiber Communication 10EC72 SYLLABUS Optical Fiber Communication Subject Code : 10EC72 IA Marks : 25 No. of Lecture Hrs/Week : 04 Exam Hours : 03 Total no. of Lecture Hrs. : 52 Exam Marks : 100 PART - A UNIT - 1 OVERVIEW OF OPTICAL FIBER COMMUNICATION: Introduction, Historical development, general system, advantages, disadvantages, and applications of optical fiber communication, optical fiber waveguides, Ray theory, cylindrical fiber (no derivations in article 2.4.4), single mode fiber, cutoff wave length, mode filed diameter. Optical Fibers: fiber materials, photonic crystal, fiber optic cables specialty fibers. 8 Hours UNIT - 2 TRANSMISSION CHARACTERISTICS OF OPTICAL FIBERS: Introduction, Attenuation, absorption, scattering losses, bending loss, dispersion, Intra modal dispersion, Inter modal dispersion. 5 Hours UNIT - 3 OPTICAL SOURCES AND DETECTORS: Introduction, LED’s, LASER diodes, Photo detectors, Photo detector noise, Response time, double hetero junction structure, Photo diodes, comparison of photo detectors. 7 Hours UNIT - 4 FIBER COUPLERS AND CONNECTORS: Introduction, fiber alignment and joint loss, single mode fiber joints, fiber splices, fiber connectors and fiber couplers. 6 Hours Dept of ECE, SJBIT Page 1 Optical Fiber Communication 10EC72 PART - B UNIT - 5 OPTICAL RECEIVER: Introduction, Optical Receiver Operation, receiver sensitivity, quantum limit, eye diagrams, coherent detection, burst mode receiver operation, Analog receivers. 6 Hours UNIT - 6 ANALOG AND DIGITAL LINKS: Analog links – Introduction, overview of analog links, CNR, multichannel transmission techniques, RF over fiber, key link parameters, Radio over fiber links, microwave photonics. Digital links – Introduction, point–to–point links, System considerations, link power budget, resistive budget, short wave length band, transmission distance for single mode fibers, Power penalties, nodal noise and chirping.
    [Show full text]
  • Introduction to Optical Communication Systems
    1. Introduction to Optical Communication Systems Optical Communication Systems and Networks Lecture 1: Introduction to Optical Communication Systems 2/ 52 Historical perspective • 1626: Snell dictates the laws of reflection and refraction of light • 1668: Newton studies light as a wave phenomenon – Light waves can be considered as acoustic waves • 1790: C. Chappe “invents” the optical telegraph – It consisted in a system of towers with signaling arms, where each tower acted as a repeater allowing the transmission coded messages over hundred km. – The first Optical telegraph line was put in service between Paris and Lille covering a distance of 200 km. • 1810: Fresnel sets the mathematical basis of wave propagation • 1870: Tyndall demonstrates how a light beam is guided through a falling stream of water • 1830: The optical telegraph is replaced by the electric telegraph, (b/s) until 1866, when the telephony was born • 1873: Maxwell demonstrates that light can be considered as electromagnetic waves http://en.wikipedia.org/wiki/Claude_Chappe Optical Communication Systems and Networks Lecture 1: Introduction to Optical Communication Systems 3/ 52 Historical perspective • 1800: In Spain, Betancourt builds the first span between Madrid and Aranjuez • 1844: It is published the law for the deployment of the optical telegraphy in Spain – Arms supporting 36 positions, 10º separation Alphabet containing 26 letters and 10 numbers – Spans: Madrid - Irún, 52 towers. Madrid - Cataluña through Valencia, 30 towers. Madrid - Cádiz, 59 towers. • 1855: It is published the law for the deployment of the electrical telegraphy network in Spain • 1880: Graham Bell invents the “photofone” for voice communications TRANSMITTER RECEIVER The transmitter consists of a The receiver is also a mirror made to be vibrated by parabolic reflector in which a the person’s voice, and then selenium cell is placed in its modulating the incident light focus to collect the variations beam towards the receiver.
    [Show full text]
  • Wireless Networks
    SUBJECT WIRELESS NETWORKS SESSION 2 WIRELESS Cellular Concepts and Designs" SESSION 2 Wireless A handheld marine radio. Part of a series on Antennas Common types[show] Components[show] Systems[hide] Antenna farm Amateur radio Cellular network Hotspot Municipal wireless network Radio Radio masts and towers Wi-Fi 1 Wireless Safety and regulation[show] Radiation sources / regions[show] Characteristics[show] Techniques[show] V T E Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor. The most common wireless technologies use radio. With radio waves distances can be short, such as a few meters for television or as far as thousands or even millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mice,keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications include the use of other electromagnetic wireless technologies, such as light, magnetic, or electric fields or the use of sound. Contents [hide] 1 Introduction 2 History o 2.1 Photophone o 2.2 Early wireless work o 2.3 Radio 3 Modes o 3.1 Radio o 3.2 Free-space optical o 3.3
    [Show full text]
  • The Modern Broadcaster's Journey from Satellite to Ip
    A CONCISE GUIDE TO… THE MODERN BROADCASTER’S JOURNEY FROM SATELLITE TO IP DELIVERY The commercial communication satellite will celebrate its 60th birthday next year but the concept is far from entering retirement. Nonetheless, as it moves into its seventh decade, the use of the satellite is rapidly evolving. As of 2020, approximately 1,400 communications satellites are orbiting the earth, delivering tens of thousands of TV channels and, increasingly, internet connectivity. Satellite communication is also a vital asset for the TV production industry, allowing live reportage to and from anywhere in the world – almost instantly. 1 Its place in the TV ecosystem is changing, much higher value. It was also well before the however, as it plays a reduced role in the on-demand content revolution. This trend delivery of video – a shift that several has led to the last major shift: the emergence underlying trends have accelerated. The first of multiplatform, over-the-top streaming is a massive proliferation of video content. over the last 15 years, which has eroded the dominance of the linear broadcaster. The Although satellite use in TV production rise of the streaming giants and specialist has been integral to high-profile live news platforms has forced broadcasters to increase and sports coverage, its role is waning. The their overall distribution capacity using last couple of decades has seen a massive Internet Protocol (IP)-centric methods. increase in live content from a broader range of leagues, niche sports, performance The trends impacting satellite’s role in events and 24-hour news networks. This the television landscape are forcing many expansion of content leads to the second broadcasters to look to their future and factor.
    [Show full text]
  • Commercial Space Industry Launches a New Phase
    Commercial Space Industry Launches a New Phase Updated December 12, 2016 Congressional Research Service https://crsreports.congress.gov R44708 Commercial Space Industry Launches a New Phase Summary Rockets, satellites, and the services they provide, once the domain of governments, are increasingly launched and managed by privately owned companies. Although private aerospace firms have contracted with federal agencies since the onset of the Space Age six decades ago, U.S. government policy has sought to spur innovation and drive down costs by expanding the roles of satellite manufacturers and commercial launch providers. Global spending on space activity reached an estimated $323 billion in 2015. Of this amount, nearly 40% was generated by commercial space products and services and 37% by commercial infrastructure and support industries. The U.S. government—including national security agencies and the National Aeronautics and Space Administration (NASA)—accounted for about 14% of global spending; government spending by other countries was responsible for the remaining 10%. The satellite and launch vehicle supply chains are global, with a small number of manufacturers. In 2015, global satellite manufacturing revenues were $6 billion; launches booked $2.6 billion in revenue. Ground stations—the largest part of the commercial space infrastructure—generated more than $100 billion in revenue, largely from geolocation and navigation equipment. The face of the U.S. space industry is changing with a government shift toward use of fixed price contracts for commercial services, new entrants with new launch products, and an increase in the use of smaller satellites: NASA’s commercial cargo program and other federal contracts are supporting the growth of the commercial launch industry, with less expensive rockets, some of which are planned to be reusable.
    [Show full text]
  • For Immediate Release
    FOR IMMEDIATE RELEASE ASTRONAUTS, EXPERTS, AND SPACE AGENCIES DISCUSS ASTEROIDS, OPPORTUNITIES, AND RISKS ON ASTEROID DAY, 30 JUNE LUXEMBOURG, 22 June 2020 /PRNewswire/ -- The Asteroid Foundation returns with Asteroid Day LIVE ​ ​ ​ Digital from Luxembourg. This year, the event is a fully digital celebration of asteroid science and exploration. Panel discussions and one-on-one interviews with astronauts and world experts will be broadcast on 30 June 2020. Each year Asteroid Day presents the public with a snap-shot of cutting-edge asteroid research from the largest ​ telescopes on Earth to some of the most ambitious space missions. Topics of discussion this year include the ​ acceleration in the rate of our asteroid discoveries and why it is set to accelerate even faster, the imminent arrival of samples from asteroid Ryugu and Bennu, the exciting preparations for the joint US-Europe mission to binary asteroid Didymos, and much more. Asteroids are the leftover remnants of the birth of the planets in the Solar System, and many are the shattered fragments of these diminutive proto-planets that never made it to maturity. “Asteroid exploration missions tell ​ us about the birth of our own planet and reveal how asteroids can serve astronauts as stepping stones to Mars,” says Tom Jones, PhD, veteran astronaut and planetary scientist, and Asteroid Day Expert Panel ​ member. Each asteroid is an individual with its own story to tell. And that’s what Asteroid Day is all about: bringing those stories to the widest audience possible. “Space and science have been an endless source of inspiration ​ for SES! This is one of the reasons why we and our partners continue to do extraordinary things in space to deliver amazing experiences everywhere on earth,” says Ruy Pinto, Chief Technology Officer at SES.
    [Show full text]
  • Long-Range Free-Space Optical Communication Research Challenges Dr
    Long-Range Free-Space Optical Communication Research Challenges Dr. Scott A. Hamilton, MIT Lincoln Laboratory and Prof. Joseph M. Khan, Stanford University The substantial benefits of free-space optical (FSO) or laser communications (lasercom) have been well known to system designers for quite some time, c.f. [1]. The free-space channel, similar to the fiber channel, provides many benefits at optical frequencies compared to radio frequencies (RF) including extremely wide unregulated bandwidth and tightly confined beams (i.e. narrow beam divergence), both of which enable low size, weight and power (SWaP) terminals. However, significant challenges are still perceived: stochastic intensity fluctuations in a received optical signal after propagating through the atmosphere, power-starved link mode of operation, and narrow transmit beams that must be precisely pointed and tracked. Since the late 1970’s the United States [2], Europe [3] and Japan [4] have actively been developing FSO technology motivated primarily for long-haul spaceborne communication systems. While early efforts were focused on maturing FSO technology, the past decade has seen significant progress toward demonstrating the practicality of FSO for multiple applications. The first high-rate demonstration of FSO between a satellite in Geosynchronous (GEO) orbit and the ground was achieved by the US during the GeoLITE experiment in 2001. A short time later, the European Space Agency (ESA) demonstrated a 50- Mbps FSO link operating at 800-nm wavelengths between their Artemis GEO satellite and: i) another ESA spacecraft in Low-Earth orbit (LEO) in 2001 [5]; ii) a ground station located in Tenerife, Spain in 2001 [6]; and iii) an airplane flying at altitudes as low as 6,000 meters outfitted with an FSO terminal developed by France’s Astrium EADS in 2006 [7].
    [Show full text]
  • Rafael Space Propulsion
    Rafael Space Propulsion CATALOGUE A B C D E F G Proprietary Notice This document includes data proprietary to Rafael Ltd. and shall not be duplicated, used, or disclosed, in whole or in part, for any purpose without written authorization from Rafael Ltd. Rafael Space Propulsion INTRODUCTION AND OVERVIEW PART A: HERITAGE PART B: SATELLITE PROPULSION SYSTEMS PART C: PROPELLANT TANKS PART D: PROPULSION THRUSTERS Satellites Launchers PART E: PROPULSION SYSTEM VALVES PART F: SPACE PRODUCTION CAPABILITIES PART G: QUALITY MANAGEMENT CATALOGUE – Version 2 | 2019 Heritage PART A Heritage 0 Heritage PART A Rafael Introduction and Overview Rafael Advanced Defense Systems Ltd. designs, develops, manufactures and supplies a wide range of high-tech systems for air, land, sea and space applications. Rafael was established as part of the Ministry of Defense more than 70 years ago and was incorporated in 2002. Currently, 7% of its sales are re-invested in R&D. Rafael’s know-how is embedded in almost every operational Israel Defense Forces (IDF) system; the company has a special relationship with the IDF. Rafael has formed partnerships with companies with leading aerospace and defense companies worldwide to develop applications based on its proprietary technologies. Offset activities and industrial co-operations have been set-up with more than 20 countries world-wide. Over the last decade, international business activities have been steadily expanding across the globe, with Rafael acting as either prime-contractor or subcontractor, capitalizing on its strengths at both system and sub-system levels. Rafael’s highly skilled and dedicated workforce tackles complex projects, from initial development phases, through prototype, production and acceptance tests.
    [Show full text]
  • Optical Communications and Networks - Review and Evolution (OPTI 500)
    Optical Communications and Networks - Review and Evolution (OPTI 500) Massoud Karbassian [email protected] Contents Optical Communications: Review Optical Communications and Photonics Why Photonics? Basic Knowledge Optical Communications Characteristics How Fibre-Optic Works? Applications of Photonics Optical Communications: System Approach Optical Sources Optical Modulators Optical Receivers Modulations Optical Networking: Review Core Networks: SONET, PON Access Networks Optical Networking: Evolution Summary 2 Optical Communications and Photonics Photonics is the science of generating, controlling, processing photons. Optical Communications is the way of interacting with photons to deliver the information. The term ‘Photonics’ first appeared in late 60’s 3 Why Photonics? Lowest Attenuation Attenuation in the optical fibre is much smaller than electrical attenuation in any cable at useful modulation frequencies Much greater distances are possible without repeaters This attenuation is independent of bit-rate Highest Bandwidth (broadband) High-speed The higher bandwidth The richer contents Upgradability Optical communication systems can be upgraded to higher bandwidth, more wavelengths by replacing only the transmitters and receivers Low Cost For fibres and maintenance 4 Fibre-Optic as a Medium Core and Cladding are glass with appropriate optical properties!!! Buffer is plastic for mechanical protection 5 How Fibre-Optic Works? Snell’s Law: n1 Sin Φ1 = n2 Sin Φ2 6 Fibre-Optics Fibre-optic cable functions
    [Show full text]
  • Low-Cost Wireless Internet System for Rural India Using Geosynchronous Satellite in an Inclined Orbit
    Low-cost Wireless Internet System for Rural India using Geosynchronous Satellite in an Inclined Orbit Karan Desai Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science In Electrical Engineering Timothy Pratt, Chair Jeffrey H. Reed J. Michael Ruohoniemi April 28, 2011 Blacksburg, Virginia Keywords: Internet, Low-cost, Rural Communication, Wireless, Geostationary Satellite, Inclined Orbit Copyright 2011, Karan Desai Low-cost Wireless Internet System for Rural India using Geosynchronous Satellite in an Inclined Orbit Karan Desai ABSTRACT Providing affordable Internet access to rural populations in large developing countries to aid economic and social progress, using various non-conventional techniques has been a topic of active research recently. The main obstacle in providing fiber-optic based terrestrial Internet links to remote villages is the cost involved in laying the cable network and disproportionately low rate of return on investment due to low density of paid users. The conventional alternative to this is providing Internet access using geostationary satellite links, which can prove commercially infeasible in predominantly cost-driven rural markets in developing economies like India or China due to high access cost per user. A low-cost derivative of the conventional satellite-based Internet access system can be developed by utilizing an aging geostationary satellite nearing the end of its active life, allowing it to enter an inclined geosynchronous orbit by limiting station keeping to only east-west maneuvers to save fuel. Eliminating the need for individual satellite receiver modules by using one centrally located earth station per village and providing last mile connectivity using Wi-Fi can further reduce the access cost per user.
    [Show full text]
  • Free Space Optics Vs Radio Frequency Wireless Communication
    I.J. Information Technology and Computer Science, 2016, 9, 1-8 Published Online September 2016 in MECS (http://www.mecs-press.org/) DOI: 10.5815/ijitcs.2016.09.01 Free Space Optics Vs Radio Frequency Wireless Communication Rayan A. Alsemmeari and Sheikh Tahir Bakhsh Faculty of Computing and Information Technology, King Abdulaziz University, Saudi Arabia E-mail: {ralsemmeari, stbakhsh}@kau.edu.sa Hani Alsemmeari Institute of Public Administration Information and Technology department E-mail: [email protected] Abstract—This paper presents the free space optics (FSO) but on very low data rates. Laser technology enhanced and radio frequency (RF) wireless communication. The the use of free space optics and is now highly dependent paper explains the feature of FSO and compares it with on the laser technology. FSO in original form was the already deployed technology of RF communication in developed by the NASA and used for the military terms of data rate, efficiency, capacity and limitations. purposes in different era as fast communication link. The The data security is also discussed in the paper for technology has many commonalities with the fiber optics identification of the system to be able to use in normal technology but behaves differently in the field due to the circumstances. These systems are also discussed in a way method of transmission for both the technologies [5, 6]. that they could efficiently combine to form the single RF technology is very old technology for system with greater throughput and higher reliability. communication. It is the wireless technology for data communication. It is considered to be in use for more Index Terms—Free Space Optics, Radio frequency, than 100 years.
    [Show full text]
  • Educator's Guide: Orion
    Legends of the Night Sky Orion Educator’s Guide Grades K - 8 Written By: Dr. Phil Wymer, Ph.D. & Art Klinger Legends of the Night Sky: Orion Educator’s Guide Table of Contents Introduction………………………………………………………………....3 Constellations; General Overview……………………………………..4 Orion…………………………………………………………………………..22 Scorpius……………………………………………………………………….36 Canis Major…………………………………………………………………..45 Canis Minor…………………………………………………………………..52 Lesson Plans………………………………………………………………….56 Coloring Book…………………………………………………………………….….57 Hand Angles……………………………………………………………………….…64 Constellation Research..…………………………………………………….……71 When and Where to View Orion…………………………………….……..…77 Angles For Locating Orion..…………………………………………...……….78 Overhead Projector Punch Out of Orion……………………………………82 Where on Earth is: Thrace, Lemnos, and Crete?.............................83 Appendix………………………………………………………………………86 Copyright©2003, Audio Visual Imagineering, Inc. 2 Legends of the Night Sky: Orion Educator’s Guide Introduction It is our belief that “Legends of the Night sky: Orion” is the best multi-grade (K – 8), multi-disciplinary education package on the market today. It consists of a humorous 24-minute show and educator’s package. The Orion Educator’s Guide is designed for Planetarians, Teachers, and parents. The information is researched, organized, and laid out so that the educator need not spend hours coming up with lesson plans or labs. This has already been accomplished by certified educators. The guide is written to alleviate the fear of space and the night sky (that many elementary and middle school teachers have) when it comes to that section of the science lesson plan. It is an excellent tool that allows the parents to be a part of the learning experience. The guide is devised in such a way that there are plenty of visuals to assist the educator and student in finding the Winter constellations.
    [Show full text]