Vayudoot Aviation

1. Clock bias is a process of correcting pseudo range for?

Satellites clock errors.

UTC errors.

Receiver clock errors.

Receiver and satellites clock errors.

2. Using GPS, the primary position information is the form of?

Spheres with the aircraft at the centres of the spheres.

Bearing and distance from the satellites.

Spheres with the satellites at the centres of the spheres.

Three-dimensional position, with the Earth's centre as the reference point.

3. What is the time taken to receive a complete navigation message (complete data set) from a satellite?

12 hours (=satellite orbit time).

24 seconds (=1 second per data frame).

25 seconds (= 1 second per data frame).

12.5 minutes (=30 seconds per data frame).

4. Which one of the following is an advantage of a multi-sensor system using inputs from a global navigation satellite (GNSS) and an inertial navigational system (INS)?

The only advantage of coupling both systems is double redundancy.

The GNSS can be used to update a drifting INS.

The activation of 'Selective Availability' can be recognised by the INS.

The average position calculated from data provided by both systems increases overall accuracy.

5. The orbital planes of the satellite navigation system NAVSTAR/GPS are

Inclined 55° to the equatorial plane.

Parallel to the equatorial plane.

Inclined 55° to the earth axis.

Inclined 90° to the equatorial plane.

6. In which frequency band do Satellite-Assisted Navigation systems (GNSS/GPS) provide position information that is available to civil aircraft?

VHF.

EHF

UHF.

SHF

7. A pseudo range in GNSS is a range based on?

Time measurement using UTC.

Time measurement using secondary radar principles.

Time measurement using the receiver clock.

Time measurement using the satellite clock.

8. One of the tasks of the GPS control segment is?

To detect the malfunctioning of satellites.

To calculate the accuracy of GPS.

To control continuously the motion of GPS satellites.

To calculate and transmit differential corrections to users.

9. In the NAVSTAR/GPS satellite navigation system, receiver clock error

Is negligible small because of the great accuracy the atomic clocks installed in the satellites.

Can be minimised by synchronisation of the receiver clock with the satellite clocks.

Is corrected by using signals from four satellites.

Is the biggest part of the total error; it cannot be corrected.

10. In relation to the satellite navigation system NAVSTAR/GPS, which of the following statements correctly describes the term 'Pseudo Random Noise (PRN)' signal?

PRN occurs i the receiver. It is caused by the signal from one satellite being received from different directions (multipath effect)

PRN is the atmospheric jamming that affects the signals transmitted by the satellites.

PRN is a code used for the identification of the satellites and the measurement of the time taken by the signal to reach the receiver.

PRN descrines the continuous electro-magnetic background noise that exists in space.

11. The GPS system used L1 and L2 frequency bands. Which band is used for the P code and which for the C/A code?

L2 is modulated with the C/A code only.

L1 is modulated with P code only.

L1 is modulated with P and C/A code only.

L2 is modulated with P and C/A codes.

12. In order to carry out an independent three-dimensional fix, Receiver Autonomous Integrity Monitoring (RAIM) and failure detection and exclusion of any faulty satellite, signal reception is required from a minimum number of how may satellites?

5

4

6.

7

13. Which of the following combinations of satellite navigation system provide the most accurate position fixes in air navigation?

GLONASS and COSPAS-SARSAT.

NNSS-Transit and GLONASS.

NAVSTAR/GPS and GLONASS.

NAVSTAR/GPS and NNSS-Transit.

14. Which of the following geometric satellite constellations provides the most accurate NAVSTAR/GPS position fix?

4 satellites with an azimuth of 90° from each other and an elevation of 45° above the horizon.

3 satellites with an azimuth of 120° from each other together and an elevation 45° above the horizon.

4 satellites with azimuth of 90° from each other and a low elevation above the horizen.

3 satellites with a low elevation above the horizon and an azimuth of 120° from each other together with a fourth directly overhead.

15. Almanac data stored in the receiver of the satellite navigation system NAVSTAR/GPS is used for the

Assignment of received PRN-codes (pseudo Random Noise) to the appropriate satellite.

Fast identification of received signals coming from visible satellites.

Correction of receiver clock error.

Recognition whether Selective Availability (SA) is operative.

16. Which of the following errors can be compensated for by a NAVSTAR/GPS receiver comparing L1 and L2 frequencies?

Multipath.

Receiver noise.

Ionospheric.

Tropospheric

17. What is the function of the control segment in GPS NAVSTAR?

To ensure that the transmitted data of the satellites is controlled and updated from time to time by ground stations.

It calculates the aircraft position.

To monitor and ensure that transmitted signals are saved and processed to utilise WAAS.

To transmit a signal used by a suitable receiver to calculate position.

18. What are the data elements transmitted by NAVSTAR GPS satellites? 1. Offset of the satellite clock from UTC 2. Ephemeris data. 3.Health data 4. Ionospheric delays. 5. Solar activity

1, 2, 3, and 4 only.

2, 3, 4 only.

1, 2, and 3 only

1, 2, 3, 4, and 5.

19. Which of the following satellite navigation system has Full Operational Capability (FOC) and is approved for specified flights under IFR conditions in Europe?

NAVSTAR/GPS.

NNSS-Transit.

GLONASS.

COSPAS-SARSAT.

20. In the NAVASTAR/GPS satellite navigation system, re-use of Selective Availability would give the option to artificially degrade the accuracy by?

Offsetting satellite clocks by a predetermined constant amount.

Dithering the satellite clock.

Using less accurate atomic clocks in a satellite for signal processing.

Shutting off selected satellites.

21. The sky search carried out by GNSS receiver?

Is done when the receiver position is in error.

Is the procedure carried out by the monitoring stations to check the accuracy of the satellite data.

Is done prior to each fix.

Involves the receiver downloading the almanac from each satellite before determining which satellites are in view.

22. The distance between a NAVSTAR/GPS satellites and receiver is

Calculated, using the WGS-84 reference system, from the known positions of the receiver.

Calculated from the Doppler shift of the known frequencies.

Determined by the time taken for the signal to arrive form the satellite multiplied by the speed of light.

Determined by the phase shift of the Pseudo Random Noise code multiplied by the speed of light.

23. The height of the NAVSTAR/GPS system above the Earth in km is?

20 200 km.

10 900 km.

10 250 km.

19 000 km.

24. RAIM is achieved

All of the above.

By ground stations determining the X, Y, and Z errors and passing the corrections to receivers using psudolites.

By ground monitoring stations determining the satellites range errors which are relayed to receives via geostationary satellites.

Within the receiver.

25. What is the minimum number of satellites required by a GPS in order to obtain a three dimensional fix?

5.

6

4.

3.

26. Signal reception is required from a minimum number of satellites that have adequate elevation and suitable geometry in order for a Satellite-Assisted Navigation System (GNSS/GPS) to carry out independent three-dimensional operation, Receiver Autonomous Integrity Monitoring (RAIM) and to isolate any faulty satellite and remove it from contributing to the navigation solution. The number of satellites is

4

7

6

5

27. In accordance with ICAO Annex 10, the NAVSTAR GPS global average 95% position accuracy in SPS should be?

13 m horizontally.

30 m horizontally.

22m is 3D.

5 m vertically.

28. The reason why the measured distance between a NAVSTAR/GPS satellite navigation system satellite and a receiver is called a "Pseudo-Range' is because the

Calculated range is based on an idealised Keplerian orbit.

Calculated range includes receiver clock error.

Movement of satellite and receiver during the distance calculate is not taken into account.

Measured distance is based on the Pseudo Random Noise code.

29. In a Satellite-Assisted Navigation System (GNSS/GPS), a fix is obtained by

Meaning the pulse length of signal received from a minimum number of satellites received in a specific sequential order.

The aircraft's receiver measuring the phase angle of signal received from a number of satellites, in known positions, and return to the aircraft's receiver.

The aircraft's receiver measuring the phase angle of signal received from a number of satellites, in known positions.

Measuring the time taken for a minimum number of satellites' transmissions, in known positions, to reach the aircraft's receiver.

30. What type of clock is used in NAVSTAR GPS satellites?

Atomic.

Laser.

Quartz.

Mechanical.

31. The inclination of a satellite (SV) is?

The angle between the SV orbit and the Equator.

90 degrees minus the angle between the SV orbit and the Equator.

The angle between the SV orbit and the Polar Place.

90 degrees minus the angle between the SV orbit and the Polar Plane.

32. In the NAVSTAR/GPS satellite navigation system, Selective Availability' (SA) gives the option to artificially degrade the accuracy by

Using a less accurate atomic clock in satellite for signal processing.

Dithering the satellite clock.

Offsetting satellite atomic clocks by a predetermined constant amount.

Shutting off selected satellites.

33. In order for a GPS receiver to perform basic RAIM functions it must use a minimum of?

Five satellites plus a barometric unit.

Four satellites.

Five satellites.

Three satellites plus a barometric unit.

34. Which of the following NAVSTAR/GPS satellite navigation system codes can be processed by 'unauthorised' civil aviation receivers?

P and Y.

C/A -and P.

P.

C/A.

35. Unauthorised civilian users of NAVSTAR GPS can access?

The C/A code.

The P and Y codes.

The C/A and P codes.

The P code.

36. In NAVSTAR GPS the PRN codes are used to?

Pass satellite time and ephemeris information.

Pass satellite time, ephemeris and other information.

Pass satellite ephemeris information.

Differentiate between satellites.

37. How is the distance between the NAVSTAR GPS SV (Space Vehicle) and the receiver determined?

By synchronising the receiver clock with the SV clock.

By measuring the tine from transmission to reception and multiplying this by the speed of light.

By reference to the SV and receiver positions to WGS84.

By measuring the time from transmission to reception and dividing by the speed of light.

38. The GPS control segment consists of?

A Master Control Station, Monitor Stations and geostationarysatellites.

A Master Control Station, Monitor Stations, Ground Antennas, and geostationary satellites.

A Master Control Stations and Ground Antennas.

A Master Control Station, and Monitor Stations.

39. What is the maximum latitude of a GPS satellite ground track?

35 N/S.

90 N/S.

55 N/S.

67.5 N/S.

40. The inclination to the equatorial plane of the NAVSTAR GPS orbits is?

35 degrees.

65 degrees.

45 degrees.

55 degrees.

41. Which of the following lists all the parameters that can be determined by a GPS receiver tracking signals from 4 different satellites?

Latitude and longitude.

Latitude, longitude, altitude and time.

Latitude, longitude and time.

Latitude, longitude and altitude.

42. How may satellites form the nominal NAVSTAR GPS constellation?

12.

36.

24.

6.

43. One of the tasks of the control segment of the satellite navigation system NAVSTAR/GPS is to

Manipulate the signals of selected satellites to reduce the precision of the position fix.

Monitor the status of the satellies.

Grant and monitor user authorisations.

Manufacture and launch the satellites.

44. In accordance with ICAO Annex 10, the GPS NAVASTAR position accuracy is SPS should be for 95% of the time?

30 metres horizontally.

5 metres vertically.

13 metres horizontally.

2 metres in 3-D.

45. EGNOS (European Geostationary Navigation Overlay System) is a form of?

Local Area Augmentation System (LAAS).

Local Area DIfferential GPS (LADGPS)

Stand alone Global Navigation Satellite System (BNSS).

Wide Area Differential GPS (WADGPS).

46. The influence of the ionosphere on the accuracy of the satellite navigation system NAVSTAR/GPS is

Negligible.

Only significant if the satellites are located at a small elevation angle above the horizon.

Minimised by computing the average of all signals.

Minimised by the receiver using a model of the atmosphere and comparing signals transmitted by the satellites.

47. In relation to the satellite navigation system NAVSTAR/GPS. 'All in View' is a term used when a receiver

Is receiving signals of all visible satellites but tracking only those of the 4 with the best geometric coverage.

Is receiving and tracking the signals of all 24 operational satellites Simultaneously.

Is tracking more than the required 4 satellites and can instantly replace any lost signal with another already being monitored.

Requires the signals of all visible satellites for navigation purpose.

48. How long does it take a NAVSTAR/GPS satellite to orbit the earth?

12 days.

Approximately 24 hours (one sidereal day).

365 days because the satellites are located in a geostationary orbit.

Approximately 12 hours (1/2 of a sidereal day).

49. In the event of the use of Selective Availability, how does this affect, if at all, the navigation accuracy of the NAVSTAR/GPS satellite navigation system?

It degrades position accuracy by manipulating satellite signals.

It degrades accuracy by reducing the number of available satellites.

It has no influence because, by selecting of the most suitable signals, the computing process in the receiver is quicker.

It increases because only signals from satellites in the most suitable geometric constellation are selected by the receiver.

50. What is the procedure to be followed if, on a flight under IFR conditions using the NAVSTAR/GPS satellite navigation system, the number of satellites required to maintain the RAIM (Receiver Autonomous Integrity Monitoring) function are not available?

A constant heading and speed must be flown until the required number of satellites are again available.

The flight has to be continued under VFR conditions.

The flight may be continued as planned if at least 4 satellites are available and the pilot monitors the GPS-System manually.

The flight may be continued using other certificated navigation systems.

Question Bank

Questions for GNSS