Global Positioning System: GPS Mapping

Global Positioning System (GPS) – What is it?

The geographic location of people can be pinpointed with ground receivers only because of the constellation of 24 well-spaced satellites that orbit the Earth. This constellation is what constitutes the GPS. The GPS has an accuracy that can pinpoint to within one meter with special military-approved equipment. With most other equipment the location accuracy is anywhere between 100 to 10 meters.

Who owns the GPS and how does it work?

Operated and owned by the U.S Department of Defense, the GPS is available for general use around the world.

This brings us back to the question about how this system works, here is information regarding that:

• 10,600 miles above the Earth in orbit lie the 21 GPS satellites and three spare satellites. These satellites are so spaced that from any point on the Earth, four satellites will be above the horizon.
• Each satellite that is present in the orbit contains a radio, an atomic clock and a computer. It is able to broadcast its changing position and time because of its understanding of its own orbit and clock.
• Any GPS receiver located on the Earth contains a computer that triangulates its own position by getting information from three or four satellites. This data is then provided in the form of a geographic location (latitude and longitude) to most of the receivers, within 100 meters.
• The position can be viewed on a map if the receiver is also equipped with a display screen.
• The presence of a fourth computer helps the computer/receiver figure out the altitude as well as the geographic location.
• Speed and direction of travel as also the estimated time of arrival to specified directions may also be calculated when there is movement.

GPS Mapping System

A GPS mapping system displays routes, tracks and waypoints in aerial photographs and topographical maps. With the help of the mapping tools available in these systems, it will be possible for you to draw your route directly on a map, search for nearby features from the information on the database and transfer your trip directly to your GPS in one click.

To install maps in the GPS unit, it needs to be fitted with software packages. This software that is known as GPS mapping software provides up to date maps to communicate with a GPS unit. Detailed information such as the location of a nearby church or petrol station as well as other useful places can be found with ease using GPS mapping.

These mapping systems are used by geologists and surveyors for a good many reasons. Geologists generally use the GPS mapping to monitor marked landmasses. The GPS satellites are also used to make sure that the four satellites are always within range of each point of the Earth as in order to find the longitude and latitude of the point the signal has to be received by three satellites. For the altitude, all four satellites need to receive the signal! On the other hand surveyors use GPS mapping for universal positioning for the generation and storing of maps. This information is then utilized to find survey markers and boundary lines.

Useful and accurate, the GPS can be used for a number of purposes!