Global Positioning System
A network of satellites that continuously transmit coded information, which makes it possible to precisely identify locations of Earth by measuring distances from the satellites.
- First GPS satellite launched in 1978.
- Constellation of 24 satellites achieved in 1994
- High orbit (12,000 miles above Earth’s surface)
- Traveling at speed of 7,000 miles an hour
- Circles Earth once every 12 hours
- Powered by solar energy
- Life of about 10 years
Different Nations and their Own GPS Programmes…….
NAVSTAR(Navigation Satellite Timing and Ranging) GLONASS(Global Navigation Satellite System GALILEO
UP COMING…….
GAGAN COMPASS
NAVSTAR system
Navigation Satellite Timing and Ranging (Official U.S. Department of Defense name for GPS)
The 3 segments of GPS
Space segment (the satellites)
Control segment (the ground stations)
User segment (you and your GPS receiver)
The Space segment
Consists of at least 24 satellites
(21 active plus 3 operating spares)
6 Orbit 4 satellites
6 x 4 = 24
The Control segment
Controls the GPS satellites by tracking them and then providing them with corrected orbital and clock (time) information.
There are five control stations located around the world – four unmanned monitoring stations and one ‘master control station’.
MASTER CONTROL STATION
Schriever AFB, Is the master controlling station entire GPS program•Located near Colorado Springs,Colorado,USA
•The "50th Space Wing’s 2nd Space Operations Squadron" is responsible for the operation of the GPS system
•Schriever AFB is the only Air Force base that has been named after a person who was living at the time. General Schriever died June 20, 2005
MONITORING STATIONS
4 Monitoring stations around the world
1.Hawaii (USA, Pacific ocean)2.Diego Garcia (Indian Ocean)3.Ascension Island (south Atlantic Ocean)4.Kwajalein, (Pacific ocean)
Hawaii GPS tracking centerAscension IslandDiego Garcia
GPS has a variety of applications
on land – scientific community, surveying
at sea – navigation by recreational boaters and fishing enthusiasts
in the air – navigation by general aviation and commercial aircraft
Basically, GPS allows you to record or create locations from places on the earth and help you to navigate to and from those spots.
Where GPS cannot be used?
Inside buildings
In caves
Parking garages
Other subterranean locations
Under water
Sources of errors
•Ionosphere and Troposphere delays
•Signal multi path
•Orbital errors
•Number of satellites visible
•‘Selective Availability’ (SA)
•Satellite geometry / shading
GPS Accessories
Remote Antenna – will a built in antenna’s view be shaded. An external antenna will allow you to use your GPS in an area where a clear view of the sky may not always be possible.
External Power Source – Cigarette lighter adapter or AC power source
Mounts – When you need your hands free.
Software – GARMIN’s MapSource Software,leica,spotrack
GPS Utility
G-Charts – To add more navigation data, cartography data cards are available.