GPS: How It Works and Its Limitations

How does GPS calculate your position?

• By measuring the distance from different satellites

• By drawing imaginary rings around satellites

• By using atomic clocks

• By transmitting a second signal

Why does a GPS receiver need to apply an unknown offset to its estimated time?

• To synchronize with the satellites' precise time

• To improve the accuracy of the position calculation

• To compensate for propagation errors

• To eliminate multipath errors

How many satellites are needed to calculate a precise GPS position?

• Two

• Three

• Four

• Five

What are propagation errors in GPS?

• Errors caused by signals bouncing off structures

• Errors due to variations in satellite orbits

• Errors resulting from electronic signals within the GPS receiver

• Errors caused by signals slowing down as they pass through the atmosphere

How can GPS compensate for propagation errors?

• By transmitting a second signal

• By using atomic clocks

• By placing GPS aerials high up on ships

• By comparing different frequencies of signals

What are multipath errors in GPS?

• Errors caused by signals slowing down as they pass through the atmosphere

• Errors due to variations in satellite orbits

• Errors resulting from signals bouncing off structures

• Errors caused by electronic signals within the GPS receiver

What are ephemeris errors in GPS?

• Errors caused by signals slowing down as they pass through the atmosphere

• Errors due to variations in satellite orbits

• Errors resulting from signals bouncing off structures

• Errors caused by electronic signals within the GPS receiver

What are relativistic errors in GPS?

• Errors caused by signals slowing down as they pass through the atmosphere

• Errors due to variations in satellite orbits

• Errors resulting from signals bouncing off structures

• Errors caused by time running differently on satellites

What is the purpose of differential GPS?

• To improve the accuracy of GPS signals

• To eliminate multipath errors

• To provide corrections for selective availability

• To compensate for relativistic errors

What is the main limitation of GPS accuracy?

• Propagation errors

• Multipath errors

• Relativistic errors

• Receiver noise