GLOBAL

POSITIONING

SYSTEM(GPS)

What’s it?• It is a Space based satellite

navigation system.• Provides : location and time

information in all weather conditions.

• Maintained by the United States government

• Accessible to anyone with a GPS Receiver.

History:• On June 26, 1993, the  U.S. Air Force

launched the 24th NAVSTAR Satellite into orbit.

• The network of 24 satellites known as GPS. •  Roger L . Easton is widely credited as

the primary inventor of GPS. •  It became fully operational in 1994.

Types of GPS:• They vary according to our need.Major types:• GPS Navigators• Hand-held GPS• GPS Trackers• Emergency GPS

It consist of three segments.

Space Segment Control Segment User Segment Calculate : three-dimensional

Location the current time.

Structure:

Segment description:• Space segment:

Composed of satellites.Constellation refers to “set of satellites”NAVSTAR composed of 24 satellites.Function : Transmit signal from space on the basis of which the time and position of the user is measured.

• Control Segment:Holds:5 ground based monitor station3 antennasa master control stationFunction:

Monitor station master controller

Antenna GPS receiver

User Segment:• Holds:GPS ReceiverUser community• Function:Converts SV Signals into

Position , time, velocity.

Working:Basically working holds three task as

follows: • The GPS transmits signals from the

satellites down to earth. • GPS Receiver then analyzes the data

that was received.• Then uses the mathematical concept

of triangulation to compute the exact location of the user.

Accuracy:

It depends upon the types of receiver.Most hand-held GPS units have about 10-20

meteraccuracy.Differential GPS (DGPS) obtains much

higheraccuracy.As recorded by the roving units, producing anaccuracy greater than 1 meter.

Advantages:

Easy to navigateGPS works in all weather.100% coverage on the planet.Easy to integrate into other technologies like

Cell phone.Best navigating system in water.

Disadvantage:GPS signals are not accurate due to some obstacles tothe signals.

Atmospheric conditions such as geomagnetic storms makes it not accurate.If GPS on a battery operated device, there may be a battery failure we need an external power supply which is not always possible

GPS Application:

• Google Earth is the most famous

application that uses the signals received

by the GPS receivers.

• United States and European countries

show a rapid growth in using GPS for the

car navigations and the number of GPS

equipped mobile phone usage.

Some Application:

• DeLorme Street Atlas 2010

• Gramin nRoute

• Top Grossing Apps on iTunes

• LOCiMOBILE Apps for tracking people

• GPS Tracking Lite v2.0

Recent Development:Block IIA:– upgraded version of the GPS Block II

satellites.– Developed by Rockwell International – As of November 2012, there were 9 Block IIA

satellites.GPS Block IIR:

-"R" in Block IIR stands for replenishment. - Developed by Lockheed Martin

-As of November 2012, there were 12 IIR satellites

Current development:

GPS Block III:

• development by Lockheed Martin

• GPS III will provide more powerful signals in

addition to enhanced signal reliability,

accuracy, and integrity.

• GPS III series is the newest block of

GPS satellites

Future of GPS:

The future will hold a lot more surprises.

Automobiles are tested on moving on their

own without the assistance of a driver.

Tests have begun in using unmanned

aircrafts.

The green plant density of a certain area

can be calculated or estimated.

Usage of GPS:

Conclusion:

• GPS has truly helped man to advance in

more ways than one.

• It is also going to bring a great revolution

by its development.

Presented by,I.Madhumithah, I M.Sc(CS).,

G.Venkataswamy Naidu College,

Kovilpatti.