Global positioning system

GLOBAL POSITIONING SYSTEM

Vitaliy VorobeyIAN - 415

What is GPS ?

The Global Positioning System (GPS) is a satellite based navigation system that can be used to locate positions anywhere on earth.

GPS is used on incidents in avariety of ways, such as:

To determine position locations; To navigate from one location to another;To create digitized maps;To determine distance between two points;

How the Global Positioning System Works The basis of the GPS is a constellation of

satellites that are continuously orbiting the earth. These satellites, which are equipped with atomic clocks, transmit radio signals that contain their exact location, time, and other information. The radio signals from the satellites, which are monitored and corrected by control stations, are picked up by the GPS receiver. A GPS receiver needs only three satellites to plot a rough, 2D position, which will not be very accurate. Ideally, four or more satellites are needed to plot a 3D position, which is much more accurate.

Three Segments of GPS

Space Segment — Satellites orbiting the earth;

Control Segment — The control and monitoring stations;

User Segment — The GPS receivers owned by �civilians and military;

How GPS Determines a Position• Precise location of satellites;�• Distance from each satellite;• Triangulation to determine position;�

Sources of Errors

User mistakes Multipath interference� Satellite and receiver �

clock errors Orbit errors� Satellite geometry Atmospheric interference Selective Availability Correction systems Real-time Differential �

GPS Wide Area Augmentation

System

Applications – Military

Military GPS user equipment has been integrated into fighters, bombers, tankers, helicopters, ships, submarines, tanks, jeeps, and soldiers' equipment.

In addition to basic navigation activities, military applications of GPS include target designation of cruise missiles and precision-guided weapons and close air support.

To prevent GPS interception by the enemy, the government controls GPS receiver exports

GPS satellites also can contain nuclear detonation detectors.

Applications – Civilian

Automobiles are often equipped GPS receivers.

For aircraft, GPS provides Agriculture Disaster Relief Marine applications Other Applications not mentioned here

include

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