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Yanah Enayah
Birzeit Uni.
14-3-2020
What is GPS?
The Global Positioning System (GPS)
is a satellite-based navigation system made up of at least 24 satellites.
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GPS works in any weather conditions, anywhere in the world, 24 hours a day, with no subscription fees or setup charges.
What is GPS?
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The U.S. Department of Defense (USDOD) originally put the satellites into orbit for military use, but they were made available for civilian use in the 1980s.
How GPS works?
How GPS works?
How GPS works?
GPS satellites circle the Earth twice a day in a precise orbit. Each satellite transmits a unique signal and orbital parameters that allow GPS devices to decode and compute the precise location of the satellite.
How?
GPS receivers use this information to calculate a user's exact location.
Essentially, the GPS receiver measures the distance to each satellite by the amount of time it takes to receive a broadcasted signal.
GPS receivers
With distance measurements from a few more satellites, the receiver can determine a user's position and display it electronically to measure your running route, map a golf course, find a way home or adventure anywhere.
What are the receivers ?
How GPS works
To calculate your 2-D position (latitude and longitude) and track movement, a GPS receiver must be locked on to the signal of at least 3 satellites.
How GPS works 2D/3d ?
How accurate is GPS?
With 4 or more satellites in view, the receiver can determine your 3-D position (latitude, longitude and altitude)
Generally, a GPS receiver will track 8 or more satellites, but that depends on the time of day and where you are on the earth. Some devices can do all of that from your wrist.
3-D Position
information calculated
Once your position has been determined, the GPS unit can calculate other information ,such as ;
-Speed.
-Direction.
-Track.
-Trip distance.
-Distance to destination.
-Sunrise and sunset time.
And more..
What's the signal?
GPS satellites broadcast at least 2 low-power radio signals
What's the signal?
Passes Through
The signals travel by line of sight, meaning they will pass through;
clouds
glass
plastic
Doesn't pass through
but will not go through most solid objects, such as;
buildings
mountains
However, modern receivers are more sensitive and can usually track through houses.
How accurate is GPS?
Today's GPS receivers are extremely accurate, thanks to their parallel multi-channel design.
- They maintain a tracking lock in dense tree-cover or in urban settings with tall buildings.
-Certain atmospheric factors and other error sources can affect the accuracy of GPS receivers.