3/8/2011. Geostationary & Non Geostationary

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1 SATELLITE & BROADCAST SYSTEMS IWD 1123 Mobile Technology What is a satellite? A specially designed and compact advanced electronics devices deployed to orbit above our earth space either on a static or dynamic manner. Providing communications and broadcast capabilities. Satellites can be divided into two principal types: Natural Satellites Orbiting moon for any planets are known as a natural satellite Artificial Satellites Object constructed by humans and placed in orbit around the earth or other celestial body The satellite is lifted from the earth's surface by a rocket and, once placed in orbit. Maintains its motion without further rocket propulsion. 1 st satellite was the Sputnik 1 a Russian satellite launch in st US satellite was the Explorer launch in 1 st Malaysia satellite was the launch in Copyrights 2007/2008 S.R Sulaiman Satellites can be divided into five principal types: Research Military, Science, Astronomy Communications Phone, VOIP, Internet Weather News, Forecasts Navigational GPS, Weapon System, Tracking Applications. Improvements and Upgrades Applications of satellite. There are many applications for satellite today's, which includes: Astronomical Communications Earth Observational Navigational Reconnaissance Weather Research satellite. (RS ) Research satellites measure fundamental properties of outer space. Early research satellites included a series of orbiting observatories Example of RS : Hubble Space Telescope, Campton Gamma Ray Observatory, Chandra X-Ray Observatory, Infra Red Observatory and Solar and Heliospheric Observatory Communication Satellite. (CS ) The most important functions of today s satellite Provide a worldwide linkup of radio, telephone, and television. First communication satellite was the Echo passive satellite Problems of early satellite: Limited applications 2 nd Generation satellite Relay 1, Telstar 1 active satellite Non continuous communications 3 rd Generation satellite Intelsat 1 active satellite The first commercial geosynchronous satellite A network of 29 Intelsat satellites in geosynchronous orbit Provides instantaneous communications throughout the world Weather Satellite. (WS ) Also known as a meteorological satellite. Provide continuous, up-to to-date information about large-scale atmospheric conditions. 1 st generation of WS : Trios 1 Transmit infrared television pictures of the earth's cloud cover 2 nd generation of WS : Nimbus Carried six cameras for more detailed scanning 3 rd generation of WS : Itos Geostationary & Night Vision Cameras Transmit visible or infrared photos Focus on a narrow or wide area Maneuver in space to obtain maximum coverage 1

2 Navigational Satellite. (NS ) Developed primarily to satisfy the need for a navigation system that nuclear submarines could use to update their inertial navigation system 1 st generation of NS : Transit 5A Transit satellites provided a constant signal by which aircraft and ships could determine their positions with great accuracy. Transit system had an inherent limitation were some areas of the globe that were not continuously covered 2 nd generation of NS : Navstar/GPS & GLONASS Consists of 24 satellites approximately 11,000 miles above the surface of the earth in six different orbital planes. Users are always in view of at least five satellites which yields highly accurate location information including altitude GLONASS will use the same number of satellites and orbits similar to those of Navstar. Low Orbit Satellite Low Earth Orbit (LEO) refers to a satellite which orbits the earth at altitudes between (very roughly) 200 miles and 930 miles. Low Earth Orbit satellites must travel very quickly to resist the pull of gravity -- approximately 17,000 miles per hour. Because of this, Low Earth Orbit satellites can orbit the planet in as little as 90 minutes. Low Earth Orbit satellite systems require several dozen satellites to provide coverage of the entire planet. Low Earth Orbit satellites typically operate in polar orbits. Low Earth Orbit satellites are used for applications where a short Round Trip Time (RTT) is very important, such as Mobile Satellite Services (MSS).Low Earth Orbit satellites have a typical service life expectancy of five to seven years. Satellite for Communication (Satellite Dish) The major types of satellite dishes are motor-driven dishes, multi-satellites, VSAT, and ad hoc satellites. Other types include DTH, SMATV, CABD, automatic tracking satellite dishes, and big ugly dishes. A motor-driven satellite dish is mounted on a pole which rotates around an axis to detect and receive various satellite signals in the sky. Multi-satellite dishes can pick up data transmissions from several satellite dishes at the same time. A VSAT (Very Small Aperture Terminal) is a 2-way satellite ground station that provides two-way way satellite Internet communication for consumers and private networks. Satellite for Communication (Satellite Dish) Ad hoc satellite dishes are used mainly as recipient reflector antennas of radio frequencies. It is easier to pick up signals on ad hoc satellite dishes when used with a DTH (Direct to Home) satellite. Orbits: Satellite Orbits If placed in an orbit high enough to escape the frictional effects of the earth's atmosphere, the motion of the satellite is controlled by the same laws of celestial mechanics that govern the motions of natural satellites and remain in orbit indefinitely Altitudes A satellite must be placed above an altitude of 320KM (200 Miles) To attain orbital altitude and velocity, multistage rockets are used, with each stage falling away as its fuel is exhausted. A satellite orbit the earth at a velocity of 8km/sec or a massive 28,800km/h At the altitude of 320km the satellite will orbit the earth at interval of 90 min per cycle. At 800km the satellite will completely cycle the earth in 100 min To make the satellite orbit the earth for 24 hour, the altitude must increase to a height of 36,000 km? Orbits: Satellite Orbits Common Satellite Placement Perigee: Also know as a placement of a satellite in an orbit nearest to the earth. Apogee: Apogee is the point at which a satellite in an elliptical orbit is furthest from the Earth. At its apogee, the satellite travels slower than at any other point in its orbit. 2

3 Orbits: Geostationary Satellite A geostationary satellite is any satellite which is placed in a geostationary orbit. Satellites in geostationary orbit maintain a constant position relative to the surface of the earth. Geostationary satellites do this by orbiting the earth approximately 22,300 miles above the equator. This orbital path is called the Clarke Belt, in honor of Arthur C. Clarke. In other words, if a satellite in a geostationary orbit is in a certain place above the earth, it will stay in that same spot above the earth. Its latitude stays at zero and its longitude remains constant. Geostationary satellites are commonly used for communications and weather-observation. Simple Quizzes Questions: What are the required altitude if you wanted your satellite to completely orbit the earth in 12 hours? If you deployed your satellite at an altitude of 320 miles, how long does it takes for the satellite to orbit the earth? What will happen to the speed/velocity of an artificial satellite as the altitude placement of the satellite increase? Will the speed also increase? Simple Quizzes Answers: What are the required altitude if you wanted your satellite to completely orbit the earth in 12 hours? * If 24 hour =36,000km 12 hour = 36,000/2 = 18,000km If you deployed your satellite at an altitude of 320 miles, how long does it takes for the satellite to orbit the earth? * 144 Minutes. (1 Miles = 1.61KM) What will happen to the speed/velocity of an artificial satellite as the altitude placement of the satellite increase? Will the speed also increase? * Speed will decrease History The three generations of mobile networks deployed to date (1G, 2G, and 3G) have been defined by their technical characteristics. To date, there have been three distinct generations of mobile cellular networks. The first three generations of mobile networks are conventionally defined by air interfaces and transport technologies. Characteristic Major functionalities 1G - Basic mobile telephony service 2G - Mobile telephony service for mass users with improved ciphering and efficient utilization of the radio spectrum. 25G 2.5G - Mobile Internet services 3G - Enhanced 2.5G services plus global roaming, and emerging new applications. 3.5G Advanced 3G services with added HSDPA, where the HSDPA is also known as High Speed Downlink Packet Access with a speed reaching 14.4Mbps. 4G Fully IP based integrated system which is capable to deliver speed of 100Mbps 1Gbps for data exchange indoor and outdoor with excellent quality and security. 2.75G and 3.75G also available but are not made popular due non linear technology applications. 3

4 Exposure GSM Also known as a Global System for Mobile communications. Is the most popular standard for mobile phones in the world. GSM differs from its predecessors in that both signaling and speech channels are digital, and thus is considered a second generation (2G) mobile phone system. GSM also pioneered a low-cost cost, to the network carrier, alternative to voice calls, the Short message service (SMS, also called "text messaging") Another advantage is that the standard includes one worldwide Emergency telephone number, 112. This makes it easier for international travelers to connect to emergency services without knowing the local emergency number. Exposure 2G Also known as a second generation mobile technology. Commercially launched on the GSM standard in Finland by Radiolinja in G networks were fully digital while previous 1G networks were analog. Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted, while on analog systems it was possible for third parties to eaves- drop on calls 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels 2G introduced data services for mobile, starting with SMS text messages. Exposure 3G Also known as Third Generation of mobile phone standards and technology Superseding 2G, and preceding 4G. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications programmed 3G technologies enable network operators to offer users a wider range of more advanced services while achieving greater network capacity. Additional features also include HSPA data transmission capabilities able to deliver speeds up to 14.4Mbit/s on the downlink and 5.8Mbit/s on the uplink. 3G networks are wide area cellular telephone networks which evolved to incorporate high-speed internet access and video telephony. Exposure 4G Also known as Beyond 3G technology or also an abbreviation for Fourth-Generation. A complete evolution in wireless communications A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an "Anytime, Anywhere" basis, and at higher data rates than previous generations. 4G will be capable of providing between 100 Mbit/s and 1 Gbit/s speeds both indoors and outdoors, with premium quality and high security. The international telecommunications regulatory and standardization bodies are working for commercial deployment of 4G networks roughly in the time scale Exposure 4G Exposure 4G 4G mobile technology as an example, will give people a more convenience and ease in lifestyle. With the anytime, anywhere, anything, capability, 4G wireless technology will benefit every individual regardless of time and place. 4

5 Exposure 4G & Beyond 3G As hype about multiple standards paths in the wireless technology has caused significant confusion in the market.?? Objectives include improving efficiency, lowering costs, improving services, making use of new spectrum opportunities, and better integration with other open standards. The aim of the project comprises of: Download rates of 100Mbps, and upload rates of 50Mbps for every 20MHz of spectrum Sub-5ms latency for small IP packets. Increased spectrum flexibility, with spectrum slices as small as 1.6MHz. Coexistence with legacy standards (users can transparently start a call or transfer of data in an area using an 3GPP LTE (Third Generation Partnership Programme Long Term) standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS) Frequency Hopping Spread Spectrum The Global Positioning System (GPS) is a satellite-based navigation system that sends and receives radio signals. A GPS receiver acquires these signals and provides you with information. Using GPS technology, you can determine location, velocity, and time, 24 hours a day, in any weather conditions anywhere in the world for free. GPS, formally known as the NAVSTAR (Navigation Satellite Timing and Ranging). Global Positioning System, originally was developed for the military. GPS technology requires the following three segments: Space segment Control segment User segment Space Segment At least 24 GPS satellites orbit the earth twice a day in a specific pattern. They travel at approximately 7,000 miles per hour about 12,000 miles above the earth s surface. These satellites are spaced so that a GPS receiver anywhere in the world can receive signals from at least four of them. Ground Antennas Ground antennas receive the corrected orbital and clock information from the MCS, and then send the corrected information to the appropriate satellites. User Segment The GPS user segment consists of your GPS receiver. Your receiver collects and processes signals from the GPS satellites that are in view and then uses that information to determine and display your location, speed, time, and so forth. Your GPS receiver does not transmit any information back to the satellites. How Accurate Is GPS? GPS technology depends on the accuracy of signals that travel from GPS satellites to a GPS receiver. You can increase accuracy by ensuring that when you use (or at least when you turn on) your GPS receiver, you are in an area with few or no obstacles between you and the wide open sky. When you first turn on your GPS receiver, stand in an open area for a few moments to allow the unit to get a good fix on the satellites (especially if you are heading into an obstructed area). This gives you better accuracy for a longer period of time (about 4-6 hours). It takes between 65 and 85 milliseconds for a signal to travel from a GPS satellite to a GPS receiver on the surface of the earth. Who Uses GPS? GPS technology has many amazing applications on land, at sea, and in the air. You might be surprised to learn about the following examples of how people or professions are already using GPS technology: Agriculture In precision farming, GPS technology helps monitor the application of fertilizer and pesticides. GPS technology also provides location information that helps farmers plow, harvest, map fields, and mark areas of disease or weed infestation. Aviation Aircraft pilots use GPS technology for en route navigation and airport approaches. Satellite navigation provides accurate aircraft location anywhere on or near the earth. Environment GPS technology helps survey disaster areas and map the movement of environmental phenomena (such as forest fires, oil spills, or hurricanes). It is even possible to find locations that have been submerged or altered by natural disasters. 5

6 Ground Transportation GPS technology helps with automatic vehicle location and in-vehicle navigation systems. Many navigation systems show the vehicle s location on an electronic street map, allowing drivers to keep track of where they are and to look up other destinations. Some systems automatically create a route and give turn-by-turn directions. GPS technology also helps monitor and plan routes for delivery vans and emergency vehicles. Marine GPS technology helps with marine navigation, traffic routing, underwater surveying, navigational hazard location, and mapping. Commercial fishing fleets use it to navigate to optimum fishing locations and to track fish migrations. Military Military aircraft, ships, submarines, tanks, jeeps, and equipment use GPS technology for many purposes including basic navigation, target designation, close air support, weapon technology, and rendezvous. Public Safety Emergency and other specialty fleets use satellite navigation for location and status information. Rail Precise knowledge of train location is essential to prevent collisions, maintain smooth traffic flow, and minimize costly delays. Digital maps and onboard inertial units allow fully-automated train control. Outdoor and exercise enthusiasts use GPS technology to stay apprised of location, heading, bearing, speed, distance, and time. In addition, they can accurately mark and record any location and return to that precise spot. Space GPS technology helps track and control satellites in orbit. Future booster rockets and reusable launch vehicles will launch, orbit the earth, return, and land, all under automatic control. Space shuttles also use GPS navigation. Surveying Surveyors use GPS technology for simple tasks (such as defining property lines) or for complex tasks (such as building infrastructures in urban centers). Locating a precise point of reference used to be very time consuming. With GPS technology, two people can survey dozens of control points in an hour. Surveying and mapping roads and rail systems can also be accomplished from mobile platforms to save time and money. Timing Delivering precise time to any user is one of the most important functions of GPS technology. This technology helps synchronize clocks and events around the world. Pager companies depend on GPS satellites to synchronize the transmission of information throughout their systems. Investment banking firms rely on this service every day to record international transactions simultaneously. End of Chapter #2 6