Effects of the Atmospheric Channel on Radio Waves continued 29 High frequency

Effects of the atmospheric channel on radio waves

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Effects of the Atmospheric Channel on Radio Waves (continued) 29 High-frequency radio waves that have short wavelengths are more susceptible to absorption and wavelengths are more susceptible to absorption and scattering , which arise due to water vapor and other atmospheric particles, than radio waves with low frequency and large wavelengths Information Technology in Theory CIS 3003 Information Technology Concepts The Global Positioning System (GPS) 30 GPS is used to provide positional information in three-dimensional space (latitude longitude and three dimensional space (latitude, longitude, and elevation) through a GPS receiver and a network of satellites Originally intended for military applications but is now also open for commercial use The GPS is a network of about 24 MEO satellites and h i h l i h Information Technology in Theory numerous Earth stations that constantly monitor these satellites
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3/25/2010 16 CIS 3003 Information Technology Concepts The Global Positioning System (GPS) (continued) 31 The basis of GPS is called triangulation (sometimes also called trilateration) Positional information can be obtained by means of triangulation, if the distance from at least three reference points is known Information Technology in Theory CIS 3003 Information Technology Concepts The Global Positioning System (GPS) (continued) 32 Information Technology in Theory
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3/25/2010 17 CIS 3003 Information Technology Concepts The Global Positioning System (GPS) (continued) 33 The distance from each satellite and the receiver is measured by generating a unique bit pattern for each measured by generating a unique bit pattern for each satellite and synchronizing it with the GPS receiver The next step is to use the positional information of the satellites to calculate the position of the receiver Information Technology in Theory CIS 3003 Information Technology Concepts The Global Positioning System (GPS) (continued) 34 Because satellites have predetermined orbits, their exact location at particular times can be stored in the exact location at particular times can be stored in the GPS receiver beforehand or periodically transmitted to the receiver Using these two pieces of information, the receiver can calculate the latitude, longitude, and elevation of the aircraft with respect to the Earth Information Technology in Theory
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