WorksheetsCAMBRIDGE - A Level -IT- Networks - Satellite Communications
Total questions: 10
Worksheet time: 5mins
Networks - Satellite Communication - What does GPS stand for?
Good Point Server
Point of Service Globe
Great Personality Selector
Global Positioning System
Networks - Satellite Communication - geostationary earth orbit - What does this describe?
A low earth orbit level - 500-1500k from earth requiring 40-80 satellites.
An alternative to butter.
A medium earth orbit level - 5000 - 12500 km from earth requiring 8 - 20 satellites for earth coverage.
A satellite orbit level - 35 800km from earth requiring just 3 satellites for global coverage.
Networks - Satellite Communication - Where is satellite data transfer best suited?
In remote areas that are not covered by wireless or wired broadband connections. these could be rural deserts, at sea or in deprived communities.
Interplanetary communications.
Where real time data applications are required.
Outside of the earths orbit.
Networks - Satellite Communication - Identify the orbit layers in which satellites operate.
Low earth orbit (LEO)
38000 ft......transmitted from globally travelling planes.
The GEO layer - geostationary earth orbit - 35800 km from earth - requiring only 3 satellites for global coverage.
Medium earth orbit (MEO)
Networks - Satellite Communication - What are the two main methods of satellite data transfer?
One way satellite broadband - sends data for download from the internet and uses a public switched (PTSN) connection for the client to upload data.
Public telephone
Two way satellite broadband - allows data to be uploaded and downloaded directly from the satellite.
Hand held transmogrifiers.
Networks - Satellite Communication - Identify some drawbacks.
Tends to be more expensive than other broadband connections.
Easier to set up than other broadband connections.
Bandwidth is often not as high as other broadband connections.
There are no drawbacks.
Networks - Satellite Communication - Television and Radio - Why can Satellite broadcasting offer more channels than traditional radio or cable?
Satellites are not restricted to areas or frequencies as they have global coverage and transmit microwaves.
Cable broadcasts are limited to areas of infrastructure provision.
It cannot!
Radio waves are dependent on frequencies available.
Networks - Satellite Communication - GPS - How does it work?
GPS works through the standard mobile network. Mobiles receive signals from the masts, pinpointing the location.
GPS is a government tracking service that follows and records the actions of individuals.
GPS works by receiving signals from at least 3 satellites and through 'trilateration' determines the distance between each satellite and the receiver. There are 24 LEO satellites that orbit the earth twice each day and at least 4 of these are in line of site from any position on earth.
GPS works by having a dedicated satellite to each receiver. Scrambled secure signals ensure that people are never unsure of their position on earth.
Networks - Satellite Communication - Identify areas in which GPS may be used.
Locating vehicles - Taxis, emergency services, company vehicles.
Navigation systems - Cars, Hill-walking- cycling.
Tracking people or objects.
Television signals.
Networks - Satellite Communication - Identify advantages and disadvantages of using GPS systems.
A disadvantage may be that line of site is required. Tunnels and large earth objects may cause errors in positioning.
GPS can provide real time information on a live map. Ideal for car navigation systems.
GPS may be dangerous in a car as people tend to amend them whilst driving.
A disadvantage may be that atmospheric conditions may distort signals, causing errors in location.
