Satellite orbits

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  • This chapter aims to introduce the basic concepts of satellite networking including appli- cations and services, circuit and packet switching, broadband networks, network protocols and reference models, characteristics of satellite networks, internetworking between satellite and terrestrial networks and convergence of network technologies and protocols. When you have completed this chapter, you should be able to:

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  • The Celestia, gliding through space toward Titan, major satellite of Saturn, faltered in her course. Her passengers, mostly mining engineers and their wives, stockholders, and a sprinkling of visitors, were aware of a cessation of the heavens' apparent gyrations, due to the halting of the ship's rotation on its axis.

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  • Tuỳ thuộc vào độ cao so với mặt đất các quỹ đạo của vệ tinh trong hệ thống thông tin vệtinh được chia thành (hình 2.1): HEO (Highly Elpitical Orbit): quỹ đạo elip cao GSO (Geostationary Orbit) hay GEO (Geostatinary Earth Orbit): quỹ đạo địa tĩnh MEO (Medium Earth Orbit): quỹ đạo trung LEO (Low Earth Orbit): quỹ đạo thấp.

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  • When seen from space, “Planet Earth” is a mix of clouds, with the majority (two thirds) of the total surface under ocean water with the remaining third of land forming what we call continents, with various degrees of increasing albedo from open water bodies, vegetation, bare soil, rocks, deserts, and snow/ice packs. In a very short time (relative to Earth's age), the modern human civilization has conquered its neighboring space with probes, satellites, and vehicles carrying humans for exploration.

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  • The AMS(R)S provides voice and data connectivity to users such as air traffic controllers, pilots and aircraft operators The AMSS comprises satellites, aeronautical earth stations (AESs), ground earth stations (GESs) and associated ground facilities such as a network coordination center. 7 Existing satellite systems in operation for aeronautical communications Inmatsat, MTSAT Iridium

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  • Since the time of Newton the basic structure of the solar system and the laws that govern the motions of the bodies within it have been well understood. One central body, the Sun, containing most of the mass of the system has a family of attendant planets in more-or-less circular orbits about it. In their turn some of the planets have accompanying satellites, including the Earth with its single satellite, the Moon. With improvements in telescope technology, and more recently through space research, knowledge of the solar system has grown apace.

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  • A low earth orbit (LEO) satellite constellation consists of a set of satellites orbiting the Earth with high constant speed at a relatively low altitude (a few thousand kilometers) [1]. Each satellite is equipped with a fixed number of antennas that allow it to communicate with ground transmitters/receivers and with other satellites. One of the major advantages of LEO satellites (as opposed to geostationary—GEO—satellites) is that they are closer to the Earth’s surface.

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  • The successful accomplishment of a space mission is dependent on proper and reliable functioning of the power system of the spacecraft in orbit. The stringent demands on performance including weight, volume, reliability, durability, and cost make the design of the spacecraft power system a challenging exercise. Further, since a space mission is inherently expensive, the necessity of optimization and built-in reliability becomes a rule rather than an exception for all the onboard systems.

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  • The Nyquist theoretical minimum bandwidth requirement. The ShannonHartley capacity theorem (and the Shannon limit) Government regulations. Technological limitations. Other system requirements (e.g satellite orbits)

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  • This is the first of two reports that address the complex issue of incorporating the needs of climate research into the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS, which has been driven by the imperative of reliably providing short-term weather information, is itself a union of heretofore separate civilian and military programs. It is a marriage of convenience to eliminate needless duplication and reduce cost, one that appears to be working.

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  • FOR VSAT NETWORKS 2 USE OF SATELLITES It isnot so important for someonewho is interested in VSAT networks to know a lot about satellites. However,a number of factors relative tosatellite orbiting and satellite-earth geometry influencethe operation and performance of VSAT networks. For instance, the relative position of the satellite with respect to the VSAT at a given instant determines the orientation of the VSAT antenna and also the carrier propagation delay value.

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  • Solar cells are optoelectronic devices that convert the energy of solar radiation directly into electricity by the photovoltaic (PV) effect. Assemblies of cells electrically connected together are known as PV modules, or solar panels. The photovoltaic effect was first recognized in the 19th century but the modern PV cells were developed in the mid-1950s. The practical application of photovoltaics started to provide energy for orbiting satellites.

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  • The ability of certain materials to convert sunlight to electricity was first discovered by Becquerel in 1839, when he discovered the photogalvanic effect. A number of other significant discoveries ultimately paved the way for the fabrication of the first solar cell in 1954 by Chapin, Fuller, and Pearson [1]. This cell had a conversion efficiency of 6%. Within 4 years, solar cells were used on the Vanguard I orbiting satellite. The high cost of boosting a payload into space readily justified the use of these cells, even though they were quite expensive.

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  • Mobile Satellite Communication∗ In principle communications satellites provide the same connectivity as terrestrial (wireless and wireline) networks. The advantages of satellites, such as fast wide-area coverage, flexible transmission parameters and cost independence due to distance, are compared with the disadvantages, such as restricted channel capacity because of the frequencies available, orbital positions, need for line-of-sight connectivity and high initial investment besides relatively long signal propagation times.

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  • The first reference to satellite communication systems was made in the mid-1940s by Arthur Clarke [1]. In this paper, Clarke described a number of fundamental issues relating to the building of a satellite network that entirely covers the earth including issues related to spectrum use, the power needed to run the network and the way of bringing the satellites to orbit. Clarke also introduced the concept of geostationary satellites, which – as explained later – orbit the earth in a radius that allows them to appear stationary from the earth’s surface....

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  • The purpose of this monograph is to formulate a quantitative and self-consistent theoretical approach to wave–particle interactions occurring in space plasmas, and present a logical development of the subject. In the Earth’s magnetosphere, Nature has given us a plasma laboratory that is accessible to observations made by radio, magnetic and electric instruments on the ground, and a great variety of instruments aboard rockets and Earth-orbiting satellites. Spacecraft are making similar observations in the more distant solar system.

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  • NASA’s exploration of planets and satellites over the past 50 years has led to the discovery of water ice throughout the solar system and prospects for large liquid water reservoirs beneath the frozen shells of icy bodies in the outer solar system. These putative subsurface oceans could provide an environment for prebiotic chemistry or a habitat for indigenous life.

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  • What can you measure and what are your limits when orbiting in space? Learn about what physical quantities you can measure and what types of sensors you can buy or build. We cover the 5 essential design limits as well: power, bandwidth, resolution, computing... and legal limitations. Explore what you can play with using your own personal satellite.

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  • Four hundred years ago, the Universe changed. Or, at least, our perception of it did, thanks to Galileo Galilei’s scrutiny of the night sky with a telescope. Within a couple of years, his observations of the Moon, phases of Venus and satellites of Jupiter shattered the old Ptolemaic model of our Solar System. To the church’s dismay, Earth assumed its rightful place as one of several planets orbiting the Sun (see page 28). Marking Galileo’s anniversary, the International Year of Astronomy seeks to remind us of the humbling nature of gazing at the heavens.

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