Satellite Systems
- Characteristics
- Orbiting objects that receive, amplify and transmit signals
- Use radio frequencies to communicate with ground stations
- Require line of sight between satellite and receiver
- Uses
- Determine location, speed and time using satellite signals
- Provides turn-by-turn directions for travel
- Collect, analyse and display spatial data
- Satellite television
- Broadcast TV signals via satellite
- Satellite phone
- Provide communication in remote areas
- Global Positioning Systems (GPS)
- Satellite navigation
- Geographic Information Systems (GIS)
- Media communication systems
How does sat nav work?
- The position/location of the car is calculated using GPS software
- Data is transmitted every few seconds
- An algorithm calculates the speed/location of the car
- The map is updated every few seconds
|
|
|
|
Wide coverage area |
Expensive setup and maintenance |
|
Real-time data transmission |
Signal interference due to weather or obstacles |
|
Improved communication in remote locations |
Limited bandwidth and capacity |
|
Accurate location tracking |
Privacy Concerns and potential for Surveillance |
Worked example
Modern-day drivers rely less on paper maps and more on satellite navigation systems (satnav). Describe the inputs, outputs and processing of a satnav when used by a driver to reach a destination.
[4]
4 of:
Destination is input by driver [1]
Exact position of motor vehicle is continually calculated using GPS [1]
Using data transmitted from 3 / 4 satellites [1]
The on board computer contains pre-stored road maps [1]
The car’s position is displayed on the map/route displayed [1]
The algorithm calculates the route from the current car’s position to the destination [1]
Makes allowances for traffic jams/roadworks [1]
The car system receives regular updates on traffic conditions [1]
Outputs the journey time/ETA of journey/voice output [1]
Calculates the journey time / ETA of journey time [1]
Outputs speed limits/cameras / warning speed limit [1]
Exam Tip
- Some people think the satnav sends signals to the satellite and the satellite did the calculations and sends the results back to the satnav - this is not how it works
- A satnav will calculate your current position using GPS - the user doesn't need to input this
