Vayudoot Aviation

1. Which of the following data, in addition to the Pseudo Random Noise (PRN) code, forms part of the so called 'Navigation Message' transmitted by NAVSTAR/GPS satellites?

Time; data to impair the accuracy of the position fix.

Almanac data; satellite status information.

Data to correct receiver clock error; almanac data.

Time; positions of the satellites.

2. In what type of nominal orbit are NAVSTAR GPS satellites placed

Pole to Pole.

Geo-stationary.

Elliptical.

Nearly Circular.

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

Inclined 55° to the equatorial plane.

Inclined 90° to the equatorial plane.

Inclined 55° to the earth axis.

Parallel to the equatorial plane.

4. How many operational satellites are required for Full Operational Capability (FOC) of the satellite navigation system NAVSTAR/GPS?

30

24

12

18

5. 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.

Offsetting satellite atomic clocks by a predetermined constant amount.

Dithering the satellite clock.

Shutting off selected satellites.

6. Differential GPS (D-GPS)?

It used to improve the accuracy of GPS signals within an area, by using data from a receiver placed at a known position as a correction to data received in the aircraft from the satellites.

Means to use the GPS receiver while in a known position, ad register the difference.

Means to find the difference between a DR position and the real position and the GPS position.

Is used to differentiate between signals from different satellites.

7. The NAVSTAR GPS system transmits in the L1 and Is frequency bands. Which bands are used for the P codes and which for the C/A codes?

Higher frequency for the C/A and P codes.

Higher frequency for the P code only.

Lower frequency for the C/A code and higher frequency for the P code.

Lower frequency for the P code and higher frequency for the C/A code.

8. At what approximate height above the WGS-84 ellipsoid are NAVSTAR/GPS satellites circling the earth?

10900 km.

19500 km.

36000 km.

20200 km.

9. The receiver aerial for a NAVSTAR/GPS system should be mounted

Inside the tail fin to minimise the influence of reflections from the wing and Fuselage.

Under the fuselage in order to receive correction data transmitted by D-GPS Stations.

In the vicinity of the receiver to avoid long transmission lines.

On the upper side of the fuselage in the vicinity of the centre of gravity.

10. Which of the following, if any, is a prerequisite if a receiver of a NAVSTAR/GPS satellite navigation system is to be used in combination with a multi sensor system?

The prescribed IFR-equipment must be in working correctly and the navigation information continuously displayed.

Multi-sensor systems are not certificated for flights under IFR conditions.

The prescribed IFR -equipment must be installed and operational.

The RAIM-function of the GPS receiver must be able to monitor all prescribed navigation systems.

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

Atomic.

Quartz.

Mechanical.

Laser.

12. What is the minimum number of satellites required for Satellite-Assisted Navigation-System (GNSS/GPS) to carry out two-dimensional operation?

4.

5.

2

3

13. How does a receiver of the NAVSTAR/GPS satellite navigation system determine the elevation and azimuth data of a satellite relative to the location of the antenna?

The data is stored in the receiver together with the Pseudo Random Noise (PRN) code.

If calculates it by using Almanac data transmitted by the satellites.

The data is determined by the satellite and transmitted together with the navigation message.

The data is based on the direction to the satellite determined at the location of the antenna.

14. 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 (GPS) to carry out independent three-dimensional operation without the Receiver Autonomous Integrity Monitoring (RAIM) function. The number of satellites is

4

3

6

5

15. 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.

Three satellites plus a barometric unit.

Five satellites.

16. 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

6

5

7

4

17. In a Satellite-Assisted Navigation System (GNSS/GPS) a position line is obtained by?

Timing the period that is taken for a transmission from the aircraft's transmitter/receiver to reach and return from the satellite in a known position.

Timing the period that is taken for the satellite's transmission to reach the aircraft receiver.

The aircraft receiver measuring the time difference between signals received from a minimum number of satellites.

The aircraft receiver measuring the phase angle of the signal received from a satellite in known position.

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

2 metres in 3-D.

30 metres horizontally.

5 metres vertically.

13 metres horizontally.

19. Which of the following procedures must be adopted if, on a flight under IFR conditions using a NAVSTAR/GPS satellite navigation system receiver, the position fix obtained from the GPS receiver differs from the position of conventional navigation systems by an unacceptable amount?

The pilot must determine the reason for the deviation and correct the error or switch off the faulty system.

It must be continued under VFR conditions.

It may be continued using conventional navigation systems.

It may be continued using NAVSTAR/GPS; prior to the next flight all system must be checked.

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

It calculates the aircraft position.

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

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.

21. How many clocks are installed in each NAVSTAR GPS satellites?

1.

3.

4.

2.

22. Which of the following statements about the accuracy that can be obtained with the LAAS (Local Area Augmentation System) of the satellite navigation system NAVSTAR GPS is correct?

A LAAS cannot correct for satellite timing or orbital position errors.

The increase in accuracy of position fixes is independent of the aircraft position in relation to the LAAS ground station.

A LAAS corrects the position of the aircraft by relaying the information via a geostationary satellite.

The closer the receiver is to the LAAS ground reference station, the more accurate is the aircraft position fix.

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

GLONASS.

NAVSTAR/GPS.

NNSS-Transit.

COSPAS-SARSAT.

24. Which of the following statements about the accuracy that can be obtained with the differential technique (D-GPS) of the satellite navigation system NAVSTAR/GRS is correct?

The increase in accuracy of position fixes is independent of the receiver position in relation to a D-GPS ground station.

A D-GPS receiver can detect and correct for SA providing a more accurate position fix.

The nearer a receiver is situated to a D-GPS ground station, the more accurate the position fix.

Only D-GPS allows position fixes accurate enough for 'N.on Precision Approaches'

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

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

26. The basic elements of the satellite navigation system NAVSTAR/GPS are the

Atomic clock, power supply and transponder.

Antenna, the receiver and the central control unit (CDU).

Main control station, the monitoring station and the ground antennas.

Control, space and user segments.

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

It degrades accuracy by reducing the number of available satellites.

It degrades position accuracy by manipulating satellite signals.

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

28. Which of the following statements concerning the L1 and L2 NAVSTAR/GPS transmission frequencies and codes is correct?

C/A and P codes are transmitted at different times on both frequencies.

The higher frequency is used to transmit both C/A and P codes.

The higher frequency is only used to transmit the P code.

The lower frequency is used to transmit both the C/A and P codes.

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

C/A.

P and Y.

C/A -and P.

P.

30. The geometric shape o the reference system for the satellite navigation system NAVSTAR/GPS, defined as WGS 84, is

A sphere.

A geoid.

A mathematical model that describes the exact shape of the earth.

An ellipsoid.

31. In GPS on which frequencies are the C/A and P codes transmitted?

The higher frequency.

Neither frequency.

The lower frequency.

Both frequencies.

32. 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.

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

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

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

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

Fast identification of received signals coming from visible satellites.

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

Recognition whether Selective Availability (SA) is operative.

Correction of receiver clock error.

34. The number of satellites required for a fully operational NACSTAR/GPS system is?

30.

24.

12.

21.

35. Which of the following coordinate system is used by the GPS receiver to determine position (Latitude, longitude and altitude)?

ED 50.

ED 87.

WGS 84.

EUREF 92.

36. Which of the following statement concerning DGPS is true?

DGPS removes SV ephemeris and clock and propagation errors.

Wide area DGPS accuracy improves the closer the aircraft is to the ground station.

DGPS can improve the accuracy of position information.

Local area DGPS gives the same improvement in accuracy regardless of the distance from the ground station.

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

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

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.

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

38. 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.

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

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

Is corrected by using signals from four satellites.

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

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

40. The GPS control segment consists of?

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

A Master Control Station, Monitor Stations and geostationarysatellites.

A Master Control Stations and Ground Antennas.

A Master Control Station, and Monitor Stations.

41. In relation to the NAVSTAR/GPS satellite navigation system, ' Search the Sky' is a

Continuous procedure performed by the receiver that searches the sky for satellites rising above the horizon.

Continuous process by the ground segment to monitor the GPS satellites.

Procedure that starts after switching on a receiver if there is no stored satellite data avaiable.

Procedure performed by the receiver to recognise new satellites becoming Operaional.

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

20 200 km.

10 250 km.

19 000 km.

10 900 km.

43. In relation to the NAVSTAR\GRS satellite navigation system, what is involved in the differential technique (D-GPS)?

Receivers from various manufacturers are operated in parallel to reduce the characteristical receiver noise error.

Fixed ground stations compute position errors and transmit correction data to a suitable receiver on the aircraft.

The difference between signals transmitted on the L1 and L2 frequencies are processed by the receiver to determine an error correction.

Signals from satellites are received by 2 different antennas which are located a fixed distance apart. This enables a suitable receive on the aircraft to recognise and correct multi-path errors.

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

The GNSS can be used to update a drifting INS.

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

45. In relation to the satellite navigation system NAVSTAR GPS, "All in View" is a term used when a receiver?

Is receiving and tracking the signals of all 24 satellite simultaneously.

Requires the signals o all visible satellites for navigation purpose.

Is tracking all currently visible satellites above the receiver's mark angle and it using them to compute position.

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

46. The sky search carried out by GNSS receiver?

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.

Is done when the receiver position is in error.

47. GPS satellites transmit on two band frequencies with different type of signal. Which of these are generally available for use by civil aviation?

L1 = coarse acquisition.

L2 = precise (P).

L2 = coarse acquisition (C/A).

L1 = precise (P).

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

6

4.

3.

5.

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

Negligible.

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

Minimised by computing the average of all signals.

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

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

Latitude, longitude and altitude.

Latitude, longitude and time.

Latitude and longitude.

Latitude, longitude, altitude and time.

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