GPS P1

GPS definition

• Measurement of surveying facility based on the reception of signals from an array of orbiting satellites

• An accurate worldwide navigational/direction finding and surveying facility based on the reception of signals from an array of orbiting satellites

• An accurate worldwide direction finding and surveying facility based on the reception of signals from am radio frequency

• worldwide navigation for finding a missing of signal

Advantages of Global Positioning System (GPS) is

• Can be record

• Cannot use when obstructed

• Can provide accurate geographic location

• Use as electronic Map (petrol station, street direction, cities, restaurants, hotels)

In GPS working concepts, the receiver ...

• calculates the distance to each satellite & triangulate its own position

• display the map on screen

• Continuous broadcast it position with ground station (minor correction)

• Own orbit & clock

In GPS working concept, the satellites ..

• calculates the distance

• display the map

• have clocks set to exactly the same time

• know their exact position in space from data sent to them from system controllers

The receiver calculates the distance using

• triangulation method

• rectangular method

• three point method

• four point method

In triangulation method..

• Need at least three signal from satellites for 2D position

• at least six signal from satellites for 3D position

• at least three different clock from satellites for position

• Distance is determined by observing the GPS signal travel time from Satellites to the receiver

GPS component consists of

• satellite segment

• user segment

• control segment

• map segment

GPS Space segment

• spend 12hrs/orbit

• Use 1575.2 MHz frequency (UHF)

• travel with speed of 7,000 miles an hour.

• 2,000 miles above us

GPS control segment

• five control stations located around the world

• The master control station "corrects" the satellite data and, together with two other antenna sites, sends ("uplinks") the information to the GPS satellites

• powered by solar energy

• it "controls" the GPS satellites by tracking them and then providing them with corrected orbital and clock (time) information

GPS User Segment

• The main function is to receive the exact position of the receiver located on the Earth's surface. Greenwich Mean Time etc.

• Data in NMEA format

• Consists of boaters, pilots, hikers, hunters, the military and ETC

• the satellite data and, together with two other antenna sites, sends ("uplinks") the information to the GPS satellites