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
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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
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.
Jane Rogers the financial manager at Plants Inc. a landscaping business in Chicago concurs that employers should ethically implement the use of GPS tracking in their companies. Rogers uses GPS to track and monitor outfield workers during working hours and argues that it increases efficiency and promotes confidence in prompt services to clients. Rogers supports the need for restrictive and regulative legislation in GPS tracking to create parameters within which employers can operate and be held accountable. She points out that she passively tracks employees during working hours and only resorts to active monitoring of employees after she has received complaints from clients. Rogers also states that she reminds her employees to turn-off their
... able to help out Military with coordinates of countries being more precise which meant less friendly fire as well as being able to learn how to send missiles through space without a country knowing who launched that attack. It also gave way to being able to fly at high altitudes and UAV’s for military having a better view.
...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.
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.
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.
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
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.
have the capability to let you talk with someone across the nation or let you
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.
There are about 31 active satellites used for GPS communication which are rotating around the earth’s axis. Their orbit is inclined 55 degrees with respect to the equator. Satellites are placed at 20,000 kilometers from the earth’s surface and their orbits are designed in such a way that each satellite rotates two orbits per day. Orbits are planned so that at least 6 satellites in view, from most area on the earth [4].
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.
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.
A satellite is defined as an object that orbits or revolves around another object. In basic terms, this relationship is due to the gravitational pull of the larger object while the smaller one has enough velocity and momentum to circle the larger one (Fitzgerald &Dennis). This is a good definition if one is only speaking of the broad principles of why and how objects attract one another and where in nature this occurs. The billions of stars and planets together make up a vast network of orbiting objects that each can rightfully be called satellites. By studying the way the Universe and Solar System works, scientists have been able to send man made devices into earth's orbit to serve the needs of a technologically developing world.