Provide location within metres or less anywhere on the globe.
Now available in many cars as an option
Created and operated by the US Department of Defense
More about GPS satellites
Constellation of 27 satellites
(24 active + 3 spare)
Orbit 12,600 miles above earth
(10,900 nautical miles)
Satellites in 12 hour orbit
First satellite launched in 1978, 24 th became operational in 1994
Selective availability was removed in May, 2000
Handheld receivers are now much more accurate
Global Positioning Systems
GPS is a revolutionary navigation system
24 satellites orbiting the earth
Provide location within metres or less anywhere on the globe.
Now available in many cars as an option
Created and operated by the US Department of Defense
How does GPS work?
Measuring distance by measuring time
Satellites send coded signals indicating their position in space and the exact time the signals are being sent
Receivers use the time it takes signal to travel from satellite to receiver to determine distance from satellite to receiver
Information from multiple satellites is used to determine position through ‘triangulation’
How does GPS work?
How does GPS work?
More about GPS receivers
A GPS receiver's job is to locate four or more satellites, figure out the distance to each, and use this information to deduce its own location.
Hand-held receivers for recreational use with accuracy of 10-15 metres
Vehicle mounted receivers for navigation or agricultural use with accuracy of < 1 metre
Backpack or tripod mounted receivers for surveying use with accuracy of 5 – 10 centimetres
More about GPS receivers
Receivers require clear line-of-sight; thus, they will not work indoors or where tall objects obscure the sky
What’s so cool about GPS?
GPS units
Can be used as a digital compass
Can be used to determine ground speed
Can store landmarks (locations)
Can be used for dynamic routing
Can be used for mapping applications
Applications of GPS
In-vehicle Navigation (car, boat, airplane)
Asset Management
Construction
Geologic Research & Mining
Military Navigation and Operations
Mapping & Surveying
Precision Agriculture
Public Health
Public Safety
Wireless Communications
Integrating GIS and GPS
Collect a series of latitude and longitude points using GPS receivers
add them into an existing digital map
Skills in
data collection/creation
GPS reading
observation
Digital photos
Collecting data
Collect data in the field using GPS
Write down point coordinates and additional data observations
- OR -
Use tracking function of your unit to store points, lines, or polygons, and write down additional observations
Using the data you collect
Manually enter the coordinates and observations into a table (Excel, etc.)
Save as a .dbf file
Use “Add X,Y” or “Add Event Theme” to create points on your map
- OR -
Use your GPS unit cable to download the data from the unit to your computer
World Scenario
Developed by the United States Department of Defense , GPS is officially named NAVSTAR GPS
Other satellite navigation systems in use or various states of development include:
Beidou – China's regional system that China has proposed to expand into a global system named COMPASS .
Galileo – a proposed global system being developed by the European Union , joined by China , Israel , India , Morocco , Saudi Arabia , South Korea , and Ukraine , planned to be operational by 2011–12.
GLONASS – Russia's global system which is being restored to full availability in partnership with India .
Indian Regional Navigational Satellite System (IRNSS) – India's proposed regional system.
QZSS – Japanese proposed regional system, adding better coverage to the Japanese Islands.
Indian Regional Navigational Satellite System
The Indian Regional Navigational Satellite System (IRNSS) is an autonomous regional satellite navigation system being developed by Indian Space Research Organisation which would be under total control of Indian government .
Development
The government approved the project in May 2006, with the intention it be implemented within six to seven years. The first satellite of the proposed constellation, developed at a cost of Rupee 1,600 crore (16 billion rupees), is expected to be launched in 2009.
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