The Global Positioning System (GPS) is a burgeoning technology, which provides unequalled accuracy and flexibility of positioning for navigation, surveying and GIS data capture. The GPS NAVSTAR (Navigation Satellite timing and Ranging Global Positioning System) is a satellite-based navigation, timing and positioning system. The GPS provides continuous three-dimensional positioning 24 hrs a day throughout the world. The technology seems to be beneficiary to the GPS user community in terms of obtaining accurate data up to about100 meters for navigation, meter-level for mapping, and down to millimetre level for geodetic positioning. The GPS technology has tremendous amount of applications in GIS data collection, surveying, and mapping.
The Global Positioning System (GPS) is a U.S. space-based radio navigation system that provides reliable positioning, navigation, and timing services to civilian users on a continuous worldwide basis -- freely available to all. For anyone with a GPS receiver, the system will provide location with time. GPS provides accurate location and time information for an unlimited number of people in all weather, day and night, anywhere in the world.
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Department of Defence. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.
The GPS is made up of three parts: satellites orbiting the Earth; control and monitoring stations on Earth; and the GPS receivers owned by users. GPS satellites broadcast signals from space that are picked up and identified by GPS receivers. Each GPS receiver then provides three-dimensional location (latitude, longitude, and altitude) plus the
Although this service sounds quite convenient and has its obvious benefits, there are other issues to be considered. For example, many ethical dilemmas that play from privacy issues. In a world when at one time you could take a walk to remove yourself from the eye of another, we not may be under constant supervision of sorts. Tracking devises are easily placed in many things, cell phones, which are used by nearly all people in today's American society, are the recent and most wide spread target for GPS. Is it ethical to track someone through an everyday devices such as a cell phone, is tracking people ethical in itself? These are the questions that must be resolved before we can celebrate the positives of such technological advancements.
To begin, the basic concept of the Global Positioning system consists of having a minimum of 24 operational satellites in orbit at an altitude of about 24,000 km above the Earth and traveling at an orbital speed of around 14,000 km/hour. At any point in time, there are always at least 4 satellites that are “visible” to your receiver (ex. iPhone). The receiver then gets information from at least 3 of these 4 satellites and uses what is called Trilateration to determine your exact position on the surface of the Earth. Trilateration, according to the Encyclopedia Britannica, is a “method of surveying in which the lengths of the sides of a triangle are measured and from this information angles are computed. By constructing a series of triangles adjacent to one another, a surveyor can obtain other distances and angles that would not otherwise be measurable.” To simplify things, trilateration is the method by which 3 satellites send a signal to a receiver which then calculates the distances to each one, and the time at which the signal was sent. The time portion of this process is essential and will be explained later on. The receiver then compares these 3 or even 4 signals and finds the common intersection between them, essentially determining where the GPS user is.
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
...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.
The following is a brief illustration of the principles of GPS. For more information see previous chapter. The Global positioning System (GPS) is a satellite-base navigation system that provides a user with proper equipment access to positioning information. The most commonly used approaches for GPS positioning are the Iterative Least Square (ILS) and the Kalman Filter (EKF) methods. Both of them are based on psuedorange equation:
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
The top two panels of Fig. 2 show the day to day variation of GPS-TEC for the month of April 2013 as observed at Agra station. Here, the vertical-TEC is shown by dotted line and the corresponding sum (m + σ) and difference (m – σ) are shown solid and dashed lines respectively. The days of occur...
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.
Have you ever seen the film Enemy of the State? How about The Bourne Identity, or any recent James Bond movie? All of these movies have something in common: they use striking graphics in the form of maps or satellite pictures – all the product of remote sensing. Remote sensing is a method by which scientists gather information about the surface of the earth from a distance. Remote Sensing can be traced back as far as the 1860s, and has since developed into the primary method of data gathering from the earth’s surface. The most important things to know about remote sensing are why it’s needed, how it works, and what it’s used for.
GPS is a navigational aid that is satellite based. It is made up of a network of 24 satellites in orbit around the world. The first satellite was launched in 1978 and the last was put into orbit in 1994. Every 10 years another satellite is put into orbit because each satellite is made to last that amount of time. The system began as a military application but in the 1980’s the government decided to make it available to everyone, anywhere, anytime. The system finds your position by measuring the time it takes to receive the signal back to the satellite. It then does that with other satellites to triangulate your position in relation to the earth. To calculate a position in 2D the system has to be locked on to at least three satellites, but for a 3D representation you need to be locked on to at least 4 satellites. Once the position is found the GPS can calculate much more info like speed, bearing, track, distance, etc… The GPS system is very accurate; Garmin (a leader in GPS technology) states that their newest receiver is accurate up to an average of 15 meters.
The technology of GIS is used to support and send information to environmental managers and mass. GIS allows the combination and analysis of various layers of those data in different areas including environmental measurements. According to the potential users, the environmental application areas of GIS are different, environmental spheres, and the specific environmental issue being investgated. In conclusion, Geographic Information System (GIS) is a kind of spatial information systems professionals in the form of a data management system. In a strict sense, this is a concentrated, storing, manipulating, and displaying geographically referenced information that a computer system having. In addition, Geographic Information System (GIS) technology can be applied to scientific investigations, resource management, property management, development planning, mapping and route planning.
Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of points and the distances and angles between them. These points are usually, but not exclusively, associated with positions on the surface of the Earth, and are often used to establish land maps and boundaries for ownership or governmental purposes. In order to accomplish their objective, surveyors use elements of geometry, engineering, trigonometry, mathematics, physics, and law.
The Global Positioning System consists of three sections, 1.satellites which are orbiting the planet, 2.there are numerous control/monitoring centers here on the ground, and 3. gps receivers which are used by their owners. The satellites send down signals from orbit, which are received by GPS receivers on the ground in the air or on the water, the GPS receiver then converts this information into a location longitude, latitude and altitude along with time.