Satellite systems Cambridge IGCSE Information & Communication Technology revision
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In plain words
Thousands of satellites circle the Earth. Some tell you where you are. Some look down and gather data. Others pass on television, phone calls and internet traffic to places no cable reaches.
4 things to know
- The Global Positioning System (GPS) finds the position of a receiver. The receiver picks up signals from several satellites and uses the times they took to arrive to work out exactly where it is.
- Satellite navigation (satnav) combines GPS with stored maps to plan a route and give directions. It saves reading a map and can avoid traffic. But maps can be out of date, signals are lost in tunnels and between tall buildings, and it can direct drivers down unsuitable roads.
- A Geographic Information System (GIS) stores, combines and displays data on maps in layers, such as roads, population and flood risk. It is used by planners, emergency services and environmental agencies.
- Media communication systems use satellites to carry television, telephone calls and internet connections. They reach remote places with no cables, but there is a short delay, and bad weather can affect the signal.
Worked example
A delivery driver uses satellite navigation. Give two advantages and one disadvantage.
- Advantage: the route is worked out automatically, so the driver does not need to read a map while driving.
- Advantage: the system can change the route to avoid traffic, and gives an estimated arrival time.
- Disadvantage: if the stored maps are out of date, the driver may be sent the wrong way.
Tips and tricks
- GPS finds a position. Satnav uses that position with maps to give directions. GIS layers data on maps. Three different things.
- Standard disadvantages of satellite systems: the signal can be lost, and the maps or data may be out of date.
It lands in your notebook with its questions as flashcards.
Satellite systems: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What does GPS do?
It needs signals from several satellites.
What does a satellite navigation system add to GPS?
It plans a route from the position.
Which is a disadvantage of satellite navigation?
No signal, no position.
What is a Geographic Information System used for?
Planners can see many kinds of data for one area.
Which is an advantage of satellite television and phones?
A dish or handset with a view of the sky is enough.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
2 questions, 4 marks. Write your answers on paper, then check them.
Satellite systems
Cambridge IGCSE Information & Communication Technology 0417 · 4 marks · papermunch.org
Name ______________________________ Date ______________
Describe how GPS works out the position of a vehicle.[2]
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The receiver in the vehicle picks up signals from several satellites. It uses the time each signal took to arrive to calculate its exact position.
Give two uses of a Geographic Information System.[2]
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Planning new roads or buildings. Helping emergency services to find the best route or the areas at risk. (Also: mapping flood risk.)
Answers: Satellite systems
- 1. The receiver in the vehicle picks up signals from several satellites. It uses the time each signal took to arrive to calculate its exact position.
- 2. Planning new roads or buildings. Helping emergency services to find the best route or the areas at risk. (Also: mapping flood risk.)