The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations. Provide location within meters or less anywhere

on the globe. Created and operated by the US Department of

Defense Orbit 20,000 Kms above earth Satellites in 12 hour orbit

Control Segment

Space Segment

User Segment

Three Segments of the GPSThree Segments of the GPS

Monitor Stations

GroundAntennas

Master Station

Kwajalein Atoll

US Space Command

Control SegmentControl Segment

Hawaii

Ascension Is.Diego Garcia

Cape Canaveral

Ground AntennaMaster Control Station Monitor Station

Knowing precise orbital location of satellites.▪ Almanac and ephemeris.

Finding the distance b/w the GPS and the satellite.▪ Distance=velocity * time

To find the time delay of Pseudo random code.

Positioning the GPS receiver.(Triangulation).

Let the receiver coordinates be the vector: (Ux, Uy, Uz)

And let the satellite coordinates be (Xi, Yi, Zi), where i = 1, 2, 3, …, the satellite number.

The ranging equations are thus: (X1 - Ux)2 + (Y1 - Uy)2 + (Z1 - Uz)2 = (PR1 – τc)2

(X2 - Ux)2 + (Y2 - Uy)2 + (Z2 - Uz)2 = (PR2 – τc)2

(X3 - Ux)2 + (Y3 - Uy)2 + (Z3 - Uz)2 = (PR3 – τc)2

(X4 - Ux)2 + (Y4 - Uy)2 + (Z4 - Uz)2 = (PR4 – τc)2

where τ is the receiver clock error.

Better accuracy in landing enhanced flight safety and better navigation service from one point to another.

Decrease unnecessary travel and fuel consumption.

Reduced the ground based operational and maintenance cost.

To determine the position and velocity of a satellite.

To guide the space craft in a defined path.

To launch the satellite in a specific position in the space.

A marine GPS system is a specialized system for navigation on the water.

Very specific information related to the sea beds, navigable channels and other useful maritime data allows boat captains to navigate safely.

Fleet and other professional fishermen use marine GPS to precisely locate their vessels, track the movements of fish, and even to predict the fish location for the next day. 

Determine the position of vehicle. Searching the Point of interest . Search of a route that is short,

less congested.  As long as technology helps, as

the navigation facilites will reach to a point, at which when vehicles will become smart vehicle, which is self-driven vehicles.

It aids the soldier in navigating without the help of a map and automatic reporting of the position of the troop to control station. 

Receiver PRN

Satellite PRN

Time Difference