GNSS/GPS

Question 1

How many satellites are there?

Answer 1

32 in 6 orbital planes.

Question 2

What info can GPS provide?

Answer 2

Position in 3D
Time
Speed determination

Question 3

Describe the basic principle of operation for the GPS system?

Answer 3

A satellite sends a signal, a receiver notes the time the signal is received. Comparing the time of transmission to the time of receipt provides a distance from the satellite

Question 4

How many satellites are needed for a 3D fix?

Answer 4

3, but 4 is needed for a more accurate fix

Question 5

What are the satellites orbit height and time?

Answer 5

20’200 km and 12h

Question 6

What three segments does the GPS system consist of?

Answer 6

1. Space segment
2. Control segment
3. User segment

Question 7

When is RAIM prediction required?

Answer 7

For RNP ops with RNP values of 0,3 or less

Question 8

What different GPS augmentation systems are available?

Answer 8

1. GBAS (LAAS)
2. SBAS (WAAS)
3. ABAS (RAIM)

Question 9

How many satellites are guaranteed to be available 95% of the time?

Answer 9

24

Question 10

How many satellites are normally visible from any point on the earth?

Answer 10

5 to 8 satellites

Question 11

How many satellites are needed to be in view for RAIM to do fault detection?

Answer 11

5

Question 12

How many satellites are needed to be in view for RAIM to do fault detection and exclusion?

Answer 12

6

Question 13

If RAIM has 5 satellites in view and there is a fault in one, will RAIM continue to operate?

Answer 13

No