Lecture 6: GPS

Question 1

GPS

Answer 1

Constellation of earth orbiting satellites maintained by USA for the purpose of defining geographic position on and above earth

Question 2

What are the 3 segments in GPS

Answer 2

Space segment (satellites) 
Control segment (base stations) 
User segment (GPS receivers)

Question 3

How does the GPS work?

Answer 3

1. Signal is sent out and the time taken to receive it is noted in the system
2. Using the signal from the satellite, possible locations of the receiver on the ground are narrowed to 2 points where the arc intersect
3. When the third satellite locates the receiver, the actual location can be determined

-THROUGH TRIANGULATION (ALL 3 SATELLITES)

Question 4

What are the challenges associated with using a GPS receiver?

Answer 4

• Selective availability
• multipath errors
• Dilution of precision

Question 5

What are ways to minimize errors?

Answer 5

Confidence interval

Question 6

How can you add additional attributes in the attribute table?

Answer 6

You can choose to edit the current table OR

you can create another table with FIOD and join the tables