Global Positioning

System

Global Positioning

System

What is GPS?What is GPS?

• A worldwide radio wave-navigation system formed from a constellation of 24+ satellites and their ground stations

• GPS uses these “man-made stars” as reference points to calculate positions accurate to a matter of meters

• A worldwide radio wave-navigation system formed from a constellation of 24+ satellites and their ground stations

• GPS uses these “man-made stars” as reference points to calculate positions accurate to a matter of meters

GPS ConstellationGPS Constellation

Who Developed GPS?Who Developed GPS?

• U.S. Department of Defense spent $12 billion to create a super precise form of worldwide positioning

• In the late days of the arms race, the U.S. military needed to be able to take out Russia’s missile system

• That ability profoundly affected the balance of power

• U.S. Department of Defense spent $12 billion to create a super precise form of worldwide positioning

• In the late days of the arms race, the U.S. military needed to be able to take out Russia’s missile system

• That ability profoundly affected the balance of power

Pre – GPSPre – GPS• Sputnik launched in 1957 by Russia

• Scientists at MIT learned they could track Sputnik’s orbit by listening to changes in its radio frequency as it came nearer or moved further away

• First step in recognizing a location on earth could be determined using radio signals from the satellite

• Sputnik launched in 1957 by Russia

• Scientists at MIT learned they could track Sputnik’s orbit by listening to changes in its radio frequency as it came nearer or moved further away

• First step in recognizing a location on earth could be determined using radio signals from the satellite

United State’s GPSUnited State’s GPS• NAVSTAR – the official name of the

U.S. Global Positioning System

• First deployed satellites in the 1970s

• The satellite completing NAVSTAR was deployed in the 1990s

• NAVSTAR – the official name of the U.S. Global Positioning System

• First deployed satellites in the 1970s

• The satellite completing NAVSTAR was deployed in the 1990s

NAVSTAR SatelliteNAVSTAR Satellite

Land vs. SeaLand vs. Sea

• Russia’s nuclear system was on land• U.S. nuclear arsenal was largely at sea

on submarines• For precise targeting, a system must

have accurate launching coordinates as well as precise target coordinates

• A submarine must surface and accurately fix its exact position quickly using GPS

• Russia’s nuclear system was on land• U.S. nuclear arsenal was largely at sea

on submarines• For precise targeting, a system must

have accurate launching coordinates as well as precise target coordinates

• A submarine must surface and accurately fix its exact position quickly using GPS

GPS SignalsGPS Signals

• Originally for military purposes• The U.S. government/military could

“fuzz” the signals which weakened the signal making it less accurate

• Could also completely disable the signals to the public (& other countries!) through encryption

• Originally for military purposes• The U.S. government/military could

“fuzz” the signals which weakened the signal making it less accurate

• Could also completely disable the signals to the public (& other countries!) through encryption

Ground Control SegmentsGround Control Segments

• Also known as Control Segments• Check both the operational health and

exact position of satellite in space• Transmit corrections • Five Ground Control Segments: Hawaii,

Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs

• Also known as Control Segments• Check both the operational health and

exact position of satellite in space• Transmit corrections • Five Ground Control Segments: Hawaii,

Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs

Land Control SegmentsLand Control Segments

How Does GPS WorkHow Does GPS Work

• Satellites broadcast radio signals to Earth with information about their location and the exact time the signal was transmitted (each satellite carries an atomic clock).

• Satellites broadcast radio signals to Earth with information about their location and the exact time the signal was transmitted (each satellite carries an atomic clock).

How it Works, continuedHow it Works, continued

• By calculating the difference between radio signals received from four or more satellites(originally used 3 for triangulation), GPS receivers on the ground can determine their own location (latitude/longitude), and elevation with great accuracy.

• By calculating the difference between radio signals received from four or more satellites(originally used 3 for triangulation), GPS receivers on the ground can determine their own location (latitude/longitude), and elevation with great accuracy.

Civilian DemandCivilian Demand

• Civilian demand for GPS products surged in 2000 when military stopped “fuzzing” signals

• Overnight, navigation devices became 10 times more accurate

• Civilian demand for GPS products surged in 2000 when military stopped “fuzzing” signals

• Overnight, navigation devices became 10 times more accurate

Civilian UsesCivilian Uses

• Fishing to freight to fleet tracking• Navigation (cars, train, boats, planes)• ONSTAR, emergency vehicles • In phones, wristwatches & dog collars • Geocaching – 800,000 active

"caches”• Construction, moviemaking, farming

equipment

• Fishing to freight to fleet tracking• Navigation (cars, train, boats, planes)• ONSTAR, emergency vehicles • In phones, wristwatches & dog collars • Geocaching – 800,000 active

"caches”• Construction, moviemaking, farming

equipment

Scientific UseScientific Use• Meteorologists gauge wind speed

and other variables• Zoologists track endangered species • Geologists study earthquakes• Technicians synchronize computer

networks for power grids to financial networks

• Meteorologists gauge wind speed and other variables

• Zoologists track endangered species • Geologists study earthquakes• Technicians synchronize computer

networks for power grids to financial networks

Effects on EconomyEffects on Economy• GPS receivers have been

miniaturized to just a few integrated circuits, thus cheaper

• Worldwide GPS market will total $75 billion by 2013

• 100,000 jobs

• GPS receivers have been miniaturized to just a few integrated circuits, thus cheaper

• Worldwide GPS market will total $75 billion by 2013

• 100,000 jobs

Updating NAVSTARUpdating NAVSTAR

• Satellites are regularly replaced as they age and fail

• As of 2009 there are currently more than 30 in space

• Extras used as spares and backups• Updating signals/frequencies to

work with other systems

• Satellites are regularly replaced as they age and fail

• As of 2009 there are currently more than 30 in space

• Extras used as spares and backups• Updating signals/frequencies to

work with other systems

Russia’s GLONASSRussia’s GLONASS• First satellite deployed in 1970s• Operational in the 1990s• 21 satellites originally + 2 from India• Can disable use by others through

encryptions • All ground control segments are

located within the former Soviet Union

• First satellite deployed in 1970s• Operational in the 1990s• 21 satellites originally + 2 from India• Can disable use by others through

encryptions • All ground control segments are

located within the former Soviet Union

Europe’s GNSSEurope’s GNSS• Galileo should be operational

sometime between 2010-2013• Full precision for military and

civilian use• Will have 30 satellites• Bases in Germany and Italy

• Galileo should be operational sometime between 2010-2013

• Full precision for military and civilian use

• Will have 30 satellites• Bases in Germany and Italy

Galileo goes InternationalGalileo goes International• Created by European Union(27 members)

• China, Israel, Ukraine, Morocco, South Korea, Norway joined efforts with Galileo

• Neutral technology available to everyone

• Created by European Union(27 members)

• China, Israel, Ukraine, Morocco, South Korea, Norway joined efforts with Galileo

• Neutral technology available to everyone

Galileo’s ServicesGalileo’s Services

• Open Service – free• Commercial Service – more

accuracy, encrypted, available for a fee

• Public Regulated Service – law enforcement, military, security

• Safety of Life Service – safety/critical transport, air traffic control

• Open Service – free• Commercial Service – more

accuracy, encrypted, available for a fee

• Public Regulated Service – law enforcement, military, security

• Safety of Life Service – safety/critical transport, air traffic control

U.S. ConcernsU.S. Concerns• Initial frequency chosen for Galileo

made it impossible to block without interfering with NAVSTAR

• Galileo agreed to use a different frequency allowing NAVSTAR to be jammed for national security

• NAVSTAR in conjunction with GALILEO is very accurate

• Initial frequency chosen for Galileo made it impossible to block without interfering with NAVSTAR

• Galileo agreed to use a different frequency allowing NAVSTAR to be jammed for national security

• NAVSTAR in conjunction with GALILEO is very accurate

WebsitesWebsites• http://web.haystack.mit.edu/pcr/wheream

i/documents/gpstutorial.htm

• http://www.trimble.com/gps/index.html

• http://science.nasa.gov/Realtime/jtrack/3d/JTrack3D.html

• http://www.spaceandtech.com/spacedata/constellations/glonass_consum.shtml

• http://web.haystack.mit.edu/pcr/whereami/documents/gpstutorial.htm

• http://www.trimble.com/gps/index.html

• http://science.nasa.gov/Realtime/jtrack/3d/JTrack3D.html

• http://www.spaceandtech.com/spacedata/constellations/glonass_consum.shtml