• It is a Space based satellite
• Provides : location and time
information in all weather
• Maintained by the United
• Accessible to anyone with a GPS
• 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.
• GPS Navigators
• Hand-held GPS
• GPS Trackers
• Emergency GPS
It consist of three segments.
the current time.
• 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
• Control Segment:
5 ground based monitor station
a master control station
Monitor station master controller
Antenna GPS receiver
Converts SV Signals into
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
• Then uses the mathematical concept of
triangulation to compute the exact location of
It depends upon the types of receiver.
Most hand-held GPS units have about 10-20 meter
Differential GPS (DGPS) obtains much higher
As recorded by the roving units, producing an
accuracy greater than 1 meter.
Easy to navigate
GPS works in all weather.
100% coverage on the planet.
Easy to integrate into other technologies like Cell
Best navigating system in water.
GPS signals are not accurate due to some obstacles to
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
• 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.
• DeLorme Street Atlas 2010
• Gramin nRoute
• Top Grossing Apps on iTunes
• LOCiMOBILE Apps for tracking people
• GPS Tracking Lite v2.0
– upgraded version of the GPS Block II satellites.
– Developed by Rockwell International
– As of November 2012, there were 9 Block IIA
GPS Block IIR:
-"R" in Block IIR stands for replenishment.
-Developed by Lockheed Martin
-As of November 2012, there were 12 IIR
GPS Block III:
• development by Lockheed Martin
• GPS III will provide more powerful signals in
addition to enhanced signal reliability, accuracy,
• 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.
• GPS has truly helped man to advance in more ways
• It is also going to bring a great revolution by its
I.Madhumithah, I M.Sc(CS).,
G.Venkataswamy Naidu College,