GPS (GLOBAL POSITIONING SYSTEM)
The Global Positioning System (GPS) is a space-based navigation system which provides information on location and time under all weather conditions, anywhere on or near the earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver. The US Department of Defense (DoD) developed the system, which originally used 24 satellites. It became fully operational in 1995. Bradford Parkinson, Roger L. Easton, and Ivan A. Getting are credited with inventing it. GPS technology was
…show more content…
GPS has become a widely deployed and useful tool for commerce, scientific uses, tracking, and surveillance. GPS's accurate time facilitates everyday activities such as banking, mobile phone operations, and even the control of power grids by allowing well synchronized hand-off switching.Many civilian applications use one or more of GPS's three basic components: absolute location, relative movement, and time transfer. The wide variety of fields of application of GPS for civilian use includes Astronomy, Cartography, Cellular telephony, Clock synchronization, Disaster relief/emergency services, Radio, aircraft tracking, Navigation, Tours, Mining, Surveying, Tectonics, etc.
The military applications of GPS include Navigation, Target tracking, Missile and projectile guidance, Search and rescue, Reconnaissance, attaching guidance kit to dumb bombs, etc.
Demodulation and decoding
Since, all of the satellite signals are modulated onto the same carrier frequency, the signals must be separated after demodulation. This is done by assigning each satellite a unique binary sequence known as a Gold code. The signals are decoded after demodulation using addition of the Gold codes corresponding to the satellites monitored by the receiver.
Data transfer and storage mechanism Data
The invention of the GPS started with Dr. Ivan Getting leaving his position at Raytheon Company, and armed with the knowledge of what was at the time the most advanced navigational technology in the world, they began developing the Global Positioning System. He, Roger L. Easton, and Bradford Parkison began in the 60’s with a constellation of 24 satellites (placed in six orbital planes) orbiting the earth at a very high altitude (about
14. George A. Chidi Jr., Qualcomm turns Cell Phones into GPS Systems. 16 Jan 2002. < http://www.pcworld.com/news/article/0,aid,80085,00.asp>
After compression, the structure data, audio and video must be multiplexed. A number of compressed TV signals are combined by a multiplexer and put unto a shared transition medium. This is done by one of the two possible kinds of multiplexers that result in either a transport or a program stream, which is suited for secure transmission paths since it can contain large amounts of information. In addition multiplexing can be done using various methods. Time division multiplexing allocates a distinct time interval for each channel in a set; with the help of synchronization and a fixed interval order the channels take turns using the common line.
GPS systems in earlier history, were primarily used by the military branches of our government to compete with other nations we had been fighting against. At the time, many people were trying to make that technology accessible to the public living in the United States. The idea of adding a GPS inside of a cell phone came to reality briefly before the year 2000. From then on, the GPS technology in cellphones has sophisticated in such a way never imaginable. A lot of good has come from this technology, but there has also been a lot of bad that has come from it as well.
...regarded GPS – an indispensable part of GIS. Discussions on cartographic principles, commercial GIS software programs, satellite images, aerial photos, and geodatabases are some of the other conspicuous omissions in this book. There is an inconsistency in the depth of topics explored; for example map projections are explored in great depth, while vector topology is merely glossed over. These omissions and inconsistencies would in my opinion make this book marginally less beneficial to all the three audiences together. However, there is something for all them; structure for engineers, equations for engineers and students, and GIS concepts for students, engineers and users. This book will therefore be undeniably valuable if used to complement the material in some of the other fundamental GIS books in the discipline. It has merits, but there is room for improvement.
There are many agencies that have the ability to perform Signals Intelligence, electronic reconnaissance and most of all signals intelligence from all available sources inducive to the environment. The United States Army uses the Joint Surveillance Target Attack Radar System (Joint STARS) as its main entity for signals collection. The Joint STARS platform was designed to provide a highly effective, real-time, collection tool to the ground task force commanders during battlefield engagements, but for the past ten years, the sensor has been used for peacekeeping missions. Army analysts can predict the enemy’s behavior by identifying choke points, potential avenues of approach and operating patterns such as supply routes and logistical points. The analysis gives the ground commander a more complete view of the enemy’s weaknesses. The United States Air Force employs the Joint STARS in a different mission than the Army. The Air Force uses Joint STARS as a battlefield management tool versus a collection tool as used for by the Army. The Air Force uses the platform to provide immediate and direct support to the Air Component Commander and continue to observe the enemy’s movement from a far distance in the sky. Providing essential data to commanders such as size, direction, and speed of the adversaries, with minimum casualties while under battlefield conditions, makes the Joint STARS an extremely effective tool. The Air Force also employs the Predator vehicles, which are unmanned aerial vehicles that are used for reconnaissance.
There was a time a person would use a roadmap to get from one location to another. Some also would stop and ask for directions. Today, you seldom see paper maps and people stopping at a local gas station for directions. Many vehicles come with a navigation system that provides a real-time map of the vehicle’s current location as well as systematic directions to requested destination.
GPS is a system of satellites radio-transmitters that orbit the planet in great numbers; their purpose is to be able to pinpoint the exact location of an individual or any type of vessel that is equipped with a receiver transmitter within a very small radius. GPS navigation has had a great impact upon society in general as well and its commercial and military applications. Global Positioning is made available at no cost to anyone who has a GPS receiver unit anywhere on the planet. A GPS unit is able to give the user longitude/latitude information as well as, altitude, traveling speed, distance traveled, distance remaining and time in any type of weather conditions imaginable.
The GPS is sensing knowledge to help with navigation with the car and destinations. Autonomous cars are not yet available on a large scale of the world such as out of the United States of America, but have been programmed and developed to travel along the roads of America. Most autonomous cars are programmed only for American roads, we have made a big step towards the future with autonomous cars, with them being only available mainly in America, they are a luxury. They are making their way to larger scale autopilot features, and will eventually be available on a larger scale.(Ali
Geographers plan new communities, decide where new highways should be placed, and establish evacuation plans. Computerized mapping and data analysis is known as Geographic Information Systems (GIS), a new frontier in geography. Spatial data is gathered on a variety of subjects and input onto a computer. GIS users can create an infinite number of maps by requesting portions of the data to plot.
Global-navigation Satellite Systems (GNSS) provide navigational data to airborne transportations and various other applications. Mainly two satellite constellations are in use today for navigational purposes. They are global positioning system (GPS) which is provided by the United States and global navigation satellite systems (GLONASS) which is provided by the Russian federation [1]. GPS and GLONASS satellites fly in medium Earth orbit (MEO) at an altitude of approximately 20,200 km and 19,100 km respectively. These satellites primarily transmit the timing and a data message consisting of its orbital parameters which are received by the GNSS receivers to calculate the range from the satellite which will further provide a relative three dimensional position and time from the satellites. Many other states are coming up with their own regional navigation satellite systems. Europe is coming up with European Geostationary Navigation Overlay Service (EGNOS), Japan is moving forward with Multifunctional Transport Satellite (MTSAT) and India is targeting to have its own regional navigation satellite systems christened as GPS Aided Geo Augmented Navigation (GAGAN) by the end of the year 2014. This will aid in providing more precise and advanced navigation. Thus the global nature of GNSS makes it necessary to have a close coordination between all of the states.
have the capability to let you talk with someone across the nation or let you
GPS aids the navigation system for accurate measurement of vehicle location [1]. Figure 2 provides an overview of navigation systems architecture used in the automotive industry. Coming to the navigation system architecture, it includes GPS antenna, GPS receiver, navigation computer, sensor interfaces, storage interfaces and a display unit.GPS antenna receives GPS signals from satellites. We have various GPS antenna configurations like, spiral helix, micro strip and planar rings. However, Popular among all is patch antenna. GPS signal uses Code Division Multiple Access (CDMA) spread spectrum to facilitate satellites to use common frequencies without interference. Also GPS signal provides two codes, course acquisition (C/A code) used for civilian
Synchronization: The receiver is able to determine when a signal begins to arrive and when it has finished. It must also know the duration of the each signal.
Having participated in the Federal Geographic Data Committee, it is evident to me that more and more federal agencies desire to analyze their data from a geospatial and cartographic perspective. The desired end is not to become GIS experts but rather have a simplified set of analytic tools on mobiles and tablets in order to bring geospatial capabilities to a large number of relatively naïve geospatial users. All technologies which transition from functional to a more conventional role in society require highly skilled hybrid specialists in the early stages of that conversion. A geospatial information systems analyst with specialized skills in development will be the most advantage in future GIS industries. The next five to ten years will bring about more GIS exposure via the web and mobile devices and ordinary intelligence analysts, directors of defense agencies, and chief of staffs’ at the pentagon will be performing sophisticated geospatial analysis via interactive web-based GIS platforms and mobile devices.