GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS)

Question 1

1. NAVSTAR/GPS operates in the band the receiver determines position by:

Answer 1

UHF, range position lines

Question 2

2. The NAVSTAR/ GPS control segment comprises:

Answer 2

a master control station, a back-up control station and five monitoring stations

Question 3

3. The orbital height and inclination of the NAVSTAR/GPS constellation are:

Answer 3

20180 km, 55°

Question 4

4. The model of the earth used for NAVSTAR/GPS is:

Answer 4

WGS84

Question 5

5. The minimum number of satellites required for a 3D fix is:

Answer 5

4

Question 6

6. The NAVSTAR/GPS operational constellation comprises how many satellites:

Answer 6

24

Question 7

7. The most accurate fixing information will be obtained from:

Answer 7

one satellite directly overhead and 3 spaced 120° apart close to the horizon

Question 8

8. The most significant error of GNSS is:

Answer 8

ionospheric propagation

Question 9

9. The frequency available to non-authorised users of NAVSTAR/GPS is:

Answer 9

1575.42 MHz

Question 10

10. The purpose of the pseudo-random noise codes in NAVSTAR/GPS is to:

Answer 10

identify the satellites

Question 11

11. The minimum number of satellites required for receiver autonomous integrity monitoring is:

Answer 11

5

Question 12

12. If a receiver has to download the almanac, the time to do this will be:

Answer 12

12.5 minutes

Question 13

13. The use of LAAS and WAAS remove the errors caused by:

Answer 13

elective availability, satellite ephemeris and clock

Question 14

14. The most accurate satellite fixing information will be obtained from:

Answer 14

NAVSTAR/GPS & GLONASS

Question 15

15. A LAAS requires:

Answer 15

an accurately surveyed site on the aerodrome and system known as a pseudolite to pass
corrections to X, Y & Z co-ordinates to aircraft

Question 16

16. The position derived from NAVSTAR/GPS satellites may be subject to the following errors:

Answer 16

propagation, selective availability, ephemeris

Question 17

17. EGNOS is:

Answer 17

a WAAS

Question 18

18. The PRN codes are used to:

Answer 18

determine the time interval between the satellite transmission and receipt of the signal at the receiver

Question 19

19. The availability of two frequencies in GNSS:

Answer 19

reduces propagation errors

Question 20

20. The NAVSTAR/GPS reference system is:

Answer 20

A geo-centred 3D Cartesian co-ordinate system fixed with reference to the prime
meridian, equator and pole

Question 21

21. The initial range calculation at the receiver is known as a pseudo-range, because it is not yet corrected for:

Answer 21

receiver clock errors

Question 22

22. The navigation and system data message is transmitted through the:

Answer 22

50 Hz modulation

Question 23

23. An all in view receiver:

Answer 23

checks all the satellites in view and selects the 4 with the best geometry for fixing

Question 24

24. When using GNSS to carry out a non-precision approach the MDA will be determined using:

Answer 24

barometric altitude

Question 25

25. If an aircraft manoeuvre puts a satellite being used for fixing into the wing shadow then:

Answer 25

the accuracy will be temporarily downgraded

Question 26

26. Which of the following statements concerning NAVSTAR/GPS time is correct?

Answer 26

The satellite runs its own time based on seconds and weeks which is correlated with
UTC