GNSS - Dgca question bank for pilots

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#1. In a Satellite Assisted Navigation system (GNSS/GPS) a position line is obtained by:

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

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

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

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

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

SHF.

UHF.

EHF.

VHF.

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

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

#5. 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. 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:

Satellite Navigation Systems determine range from the time travel of radio waves. In the

Navstar Global Positioning System operated by the USA, the radio waves are transmitted

from satellites orbiting the earth in orbits that are tilted at 55 degrees to the Equator,

approximately 20000 km above the earth.

The frequencies used are in the UHF waveband at frequencies of 1575.42 MHz and

1227.6 MHz.

The position of the aircraft is determined by timing the period that is taken for a satellite’s

transmission to reach the aircraft’s receiver. Simultaneous ranging form two satellites

provides an initial fix, whilst range from a third satellite will confirm the accuracy of this

fix.

If signals from a fourth satellite are available this will enable both the vertical and

horizontal positions to be determined. If a fifth satellite is available this will make it

possible to determine whether any are in error.

Signal reception from at least six satellites that have adequate elevation and suitable

geometry in order for a Satellite-Assisted Navigation System (GNSS/GPS) are required 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.

To carry out independent three-dimensional operation, Receiver Autonomous Integrity Monitoring (RAIM), and to detect and isolate a faulty satellite, a GNSS/GPS receiver requires signals from a minimum of:

6 satellites

Here’s why:

4 satellites are needed for a basic 3D position fix (latitude, longitude, altitude, and time).
5 satellites are required for RAIM to detect a faulty satellite.
6 satellites are required for RAIM to not only detect but also isolate and exclude the faulty satellite from the solution.

#7. Which of the following lists are all errors that affect the accuracy and reliability of the Satellite-Assisted Navigation system (GNSS/GPS)?

Satellite mutual interference; satellite ephemeris; atmospheric propagation.

Satellite clock; satellite ephemiris; atospheric propagation.

Satellite to ground time lag; atmospheric propagation; satellite clock.

Satellite mutual interference; frequency drift; satellite to ground time lag;

#8. 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.

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.

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

#9. GPS satellites transmit on two L-band frequencies with different types of signals. Which of these are generally available for use by civil aviation?

L20-coarse acquisition (C/A).

L1-precise(P).

L1-coarse acquisition (C/A) with selected availability(S/A).

L2-for communications purpose.

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

ED 87.

ED 50.

EUREF 92.

WGS 84.

#11. 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 and time.

Latitude, longitude and altitude.

Latitude, longitude, altitude and time.

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

NAVSTAR/GPS and NNSS-Transit.

NAVSTAR/GPS and GLONASS.

NNSS-Transit and GLONASS.

GLONASS and COSPAS-SARSAT.

#13. The required 24 NAVSTAR/GPS operational satellites are located on:

6 orbital planes with 4 satellites in each plane.

3 orbital planes with 8 satellites in each plane.

4 orbital planes with 6 satellites in each plane.

6 orbital planes with 4 satellites in each plane plus 6 reserve satellites positioned in a geostationary orbital plane.

#14. Which of the following statements about the ‘visibility’ of NAVSTAR/GPS satellites is correct?

It is the same throughout the globe.

It is greatest at the equator.

It varies, depending on the time and observer's location.

It is greatest at the poles.

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

18.

24.

12.

30.

#16. GPS systems transmit their signals on two carrier waves 1575 MHz and 1227 MHz and supply two possible codes accessible according to user (civil or military). Commercial aviation uses?

Only the 1 1575 MHz carrier wave and one code.

Only the 1 1575 MHz carrier wave and two codes.

Only the 1 227 MHz carrier wave and one code.

The two carrier waves and one public code.

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

NNSS-Transit.

COSPAS-SARSAT.

NAVSTAR/GPS.

GLONASS.

#18. The basic elements of the satellite navigation system NAVSTAR/GPS are the:

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

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

Atomic clock, power supply and transponder.

Control, space and user segments.

#19. One of the tasks of the control segment of the satellite navigation system NAVSTAR/GPS is to:

Manufacture and launch the satellites.

Monitor the status of the satellies.

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

Grant and monitor user authorisations.

#20. The main task of the user segment (receiver) of the satellite navigation system NAVSTAR/GPS is to calculate receiver position by:

Select appropriate satellites automatically, to track the signals and to measure the time taken by signals fro the satellites to reach the receiver.

Transit signals which, from the time taken, are used used to determine the distance to the satellite.

To monitor the status of the satellites, determine their positions and to measure the time.

Monitor the orbital planes of the satellites.

#21. One of the tasks of the space segment of the satellite navigation system NAVSTAR/GPS is to:

Transmit signals to suitable receivers and to monitor the orbital planes Auronomously.

Compute the user position from the received user messages and to transmit the computed position back to the user segment.

Monitor the satellites' orbits and status.

Transmit signals which can be used, by suitable receivers, to determine time, position and velocity.

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

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

A sphere.

An ellipsoid.

A geoid.

#23. In civil aviation, the height value computed by the receiver of the satellite navigation system NAVSTAR/GPS is the:

Geometric height above ground.

Height above Mean Sea Level (MSL).

Height above the WGS-84 ellipsoid.

Flight level.

#24. In relation to the satellite navigation system NAVSTAR/GPS, the term ‘inclination’ denotes the angle between the?

Horizontal plane at the locatior of the receiver and the direct line to a satellite.

Orbital plane and the equatorial plane.

Orbital plane and the earth's axis.

Horizontal plane at the location of the receiver and the orbital plane of a satellite.

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

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

Approximately 24 hours (one sidereal day).

12 days.

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

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

10900 km.

36000 km.

19500 km.

20200 km.

#27. 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.

#28. In which frequency bands are the L1 and Ls frequencies used by the satellite navigation system NAVSTAR/GPS for transmission of the navigation message?

VHF.

EHF.

UHF.

SHF.

#29. 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 the atmospheric jamming that affects the signals transmitted by the satellites.

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

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

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.

#30. Which of the following NAVSTAR/GPS satellite navigation system codes can be processed by ‘unauthorised’ civil aviation receivers?

C/A.

C/A -and P.

P and Y.

#31. 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.

Recognition whether Selective Availability (SA) is operative.

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

Correction of receiver clock error.

#32. How does a NAVSTAR/GPS satellite navigation system receiver recognise which of the received signals belongs to which satellite?

The Doppler shift is unique to each satellite.

The receiver detects the direction from which the signals are received an compares this information with the calculated positions of the satellites.

Each satellite transmits its signal on a separate frequency.

Each satellite transmits its signal, on common frequencies, with an individual Pseudo Random Noise code.

#33. 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.

#34. In the NAVSTAR/GAS satellite navigation system, what is the maximum time taken to receive the complete set of almanac data from all satellites?

12 hours (=period of the satellites orbit).

25 seconds (= 1 second per data frame).

12.5 minutes (=30 seconds per data frame).

24 seconds (=1 second per data frame).

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

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

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

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.

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

Ionospheric.

Multipath.

Tropospheric.

Receiver noise.

#37. Which of the following statements is correct concerning the principle behind the correction of one of the NAVSTAR/GPS satellite navigation system errors by the transmission of the signals on two frequencies (L1 and L2)?

The effect of receiver noise can be reduced due to the interference of both frequencies.

The effect of signal reflection (multipath effect) can be reduced due to the interference of both frequencies.

The path delay of the signals in the earth atmosphere is proportional to the inverse of the carrier frequency squared..

The influence of shadowing on the GPS signals is proportional to the inverse of the carrier frequency squared.

#38. Concerning the NAVSTAR/GPS satellite navigation system, what is the meaning of the term ‘Receiver Autonomous Integrity Monitoring’ (RAIM)?

It is the ability of the GPS satellites to check the integrity of the data transmitted by the monitoring stations of the ground segment.

It is a technique by which a receiver checks the reliability of the signal it is receiving and can detect if one of the signals is incorrect.

It is a method whereby a receiver ensures the integrity of the Pseudo Random Noise (PRN) code transmitted by the satellites.

It is technique whereby the receivers of the world-wide distributed monitor stations (ground segment) automatically determines the integrity of the navigation message.

#39. The distance between a NAVSTAR/GPS satellites and receiver is:

Calculated from the Doppler shift of the known frequencies.

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

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.

#40. In relation to the satellite navigation system NAVSTAR/GPS. ‘All in View’ is a term used when a receiver:

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

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.

Requires the signals of all visible satellites for navigation purpose.

#41. 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:

Measured distance is based on the Pseudo Random Noise code.

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

Calculated range is based on an idealised Keplerian orbit.

Calculated range includes receiver clock error.

#42. What type of satellite navigation system NAVSTAR/GPS receiver is most suitable for use of board an aircraft?

Sequential.

Multi-channel.

Multiplex.

Any hand held type.

#43. What is the minimum number of NAVSTAR/GPS staellites required to produce an accurate independent 3-D position fix?

24.

#44. The receiver aerial for a NAVSTAR/GPS system should be mounted:

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

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

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

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

#45. In the NAVSTAR/GPS satellite navigation system, Selective Availability’ (SA) gives the option to artificially degrade the accuracy by:

Shutting off selected satellites.

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

Dithering the satellite clock.

Offsetting satellite atomic clocks by a predetermined constant amount.

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

It degrades position accuracy by manipulating satellite signals.

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.

#47. In the NAVSTAR/GPS satellite navigation system, receiver clock error:

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

Is corrected by using signals from four satellites.

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

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

#48. The influence of the ionosphere on the accuracy of the satellite navigation system NAVSTAR/GPS is:

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.

Negligible.

#49. 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 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.

The only advantage of coupling both systems is double redundancy.

#50. What are the effects, if any, of shadowing by parts of the aircraft (e.g.wing) on the reception of signals from NAVSTAR/GPS satellites?

It causes multi-path propagation.

It may prevent the reception of signals.

The signals will be distorted, however the error can be corrected for using an algorithm and information fro unaffected signals.

It has no influence because high frequency signals are unaffected.

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

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

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

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

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.

#53. 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.

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

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

#54. 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?

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

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

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

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

#55. In relation to the NAVSTAR/GPS satellite navigation system, ‘ Search the Sky’ is a:

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.

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

#56. 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?

The flight has to be continued under VFR conditions.

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

The flight may be continued using other certificated navigation systems.

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

#57. 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.

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.

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

#58. 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?

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.

It must be continued under VFR conditions.

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

#59. What datum is used for the Minimum Descent Altitude (MDA) on a non- precision approach when using the NAVSTAR/GPS satellite navigation system?

If using Differential-GPS (D-GPS) the altitude obtained from the D-GPS, otherwise barometric altitude.

Radar altitude.

GPS altitude.

Barometric altitude.

#60. Which of the following is the datum for altitude information when conducting flights under IFR conditions on airways using the NAVSTAR/GPS satellite navigation system?

Barometric altitude.

The average of GPS altitude and barometric altitude.

GPS altitude.

GPS altitude if 4 or more satellites are received otherwise barometric altitude

#61. How may satellites form the nominal NAVSTAR GPS constellation?

12.

36.

24.

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

#63. 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 = coarse acquisition (C/A).

L2 = precise (P).

L1 = precise (P).

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

Geo-stationary.

Elliptical.

Nearly Circular.

Pole to Pole.

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

30 m horizontally.

13 m horizontally.

5 m vertically.

22m is 3D.

#66. Which of the following NAVSTAR/GPA satellite navigation system codes can be processed by “unauthorised” civil aviation receivers?

C/A.

C/A and P.

P and Y.

#67. 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?

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

Shutting off selected satellites.

Offsetting satellite clocks by a predetermined constant amount.

Dithering the satellite clock.

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

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

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

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

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.

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

#70. What is EGNOS (European Global Navigation Overlay System)?

Wide Area Differential GPS (WADGPS).

GLONASS.

Local Area Augmented System (LADGPS).

Local Area Differential GPS (LADGPS).

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

65 degrees.

55 degrees.

35 degrees.

45 degrees.

#72. In relation to the satellite navigation system NAVSTAR GPS, “All in View” is a term used when a receiver?

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.

Requires the signals o all visible satellites for navigation purpose.

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

#73. 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.

2 metres in 3-D.

13 metres horizontally.

#74. One of the tasks of the GPS control segment is?

To detect the malfunctioning of satellites.

To calculate and transmit differential corrections to users.

To calculate the accuracy of GPS.

To control continuously the motion of GPS satellites.

#75. One of the tasks of the GPS control segment is?

To regulate the transmitted power of the satellites.

To calculate and transmit differential corrections to users which are able to receiver Wide Area Differential GPS systems.

To control continuously the position and motion of GPS satellites.

To determine and send new ephemeris and new satellite clock errors data to the GPS satellites.

#76. For what reason is a mask angle set-up in a GPS receiver?

To deny the receiver the use of GPS satellites with an elevation less than the mask angle.

To make the receiver select GPS satellites with a certain optimum elevation Which is about equal to the mask angle.

To select from the visible GPS satellites the satellite-configuration which results in the smallest GDOP.

To eliminate the reception of the signal from GPS satellites with an elevation of about 90 degrees.

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

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

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

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

Wide Area Differential GPS (WADGPS).

Local Area DIfferential GPS (LADGPS)

Stand alone Global Navigation Satellite System (BNSS).

Local Area Augmentation System (LAAS).

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

90 N/S.

67.5 N/S.

35 N/S.

55 N/S.

#80. The GPS control segment consists of?

A Master Control Stations and Ground Antennas.

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

A Master Control Station, Monitor Stations and geostationarysatellites.

A Master Control Station, and Monitor Stations.

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

10 250 km.

10 900 km.

19 000 km.

20 200 km.

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

12.

21.

24.

30.

#83. Differential GPS (D-GPS)?

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

Is used to differentiate between signals from different satellites.

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

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.

#84. Which of the following statement concerning DGPS is true?

DGPS removes SV ephemeris and clock and propagation errors.

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

DGPS can improve the accuracy of position information.

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

#85. 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?

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

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

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.

#86. A pseudo range in GNSS is a range based on?

Time measurement using secondary radar principles.

Time measurement using UTC.

Time measurement using the satellite clock.

Time measurement using the receiver clock.

#87. A pseudo range is GNSS is in error to the actual range because?

Ionospheric delays.

Receiver clock error.

Satellite clock error.

All of these errors.

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

Receiver clock errors.

UTC errors.

Satellites clock errors.

Receiver and satellites clock errors.

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

Spheres with the aircraft at the centres of the spheres.

Spheres with the satellites at the centres of the spheres.

Bearing and distance from the satellites.

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

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

12 hours (=satellite orbit time).

25 seconds (= 1 second per data frame).

12.5 minutes (=30 seconds per data frame).

24 seconds (=1 second per data frame).

#91. The time taken for a GNSS receiver to download the satellite almanac for NAVSTAR GPS is?

12 hours.

15 minutes.

30 seconds.

12.5 minutes.

#92. 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, 4, and 5.

2, 3, 4 only.

1, 2, and 3 only

1, 2, 3, and 4 only.

#93. RAIM is achieved?

Within the receiver.

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

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

All of the above.

#94. In NAVSTAR GPS the PRN codes are used to?

Remove receiver clock error.

Determine satellite range.

Reduce ionospheric and tropospheric errors.

Eliminate satellite clock error and ephemeris error.

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

Three satellites plus a barometric unit.

Four satellites.

Five satellites.

Five satellites plus a barometric unit.

#96. What is RAIm and what is its function?

Integrity monitoring of satellites by the receiver to ensure accurate navigation.

GPS integrity monitoring of master and slave stations to ensure correct alignment.

Resolution and intensity monitoring for increased accuracy.

Integrity monitoring of satellites by the master station to increase accuracy.

#97. In NAVSTAR GPS the PRN codes are used to?

Differentiate between satellites.

Pass satellite ephemeris information.

Pass satellite time, ephemeris and other information.

Pass satellite time and ephemeris information.

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

L1 is modulated with P code only.

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

L2 is modulated with the C/A code only.

L2 is modulated with P and C/A codes.

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

The lower frequency.

The higher frequency.

Neither frequency.

Both frequencies.

#100. Unauthorised civilian users of NAVSTAR GPS can access?

The C/A code.

The P code.

The P and Y codes.

The C/A and P codes.

#101. Concerning NAVSTAR GPS orbits, which of the following statements is correct?

The orbits are geostationary to provide global coverage.

The inclination of the orbits is 55 degrees with an orbital period of 24 hours.

The inclination is 55 degrees with an orbital period of 12 hours.

The orbits are inclined at 65 degrees with an orbital period of 11 hours 15 minutes.

#102. Which of the following statements is true in respect of GNSS?

The P code is for authorised (military) use only.It is transmitted only one L1.

The C/A code is for authorised (military) use only.It is transmitted only one L1 and L2.

The P code is the only code authorised for civilian use. It is transmitted on L.

The C/A code is the only code available for civilian use. It is transmitted only on L1.

#103. Of the types of GPS receivers available for civilian aviation, which are the most advanced type?

The multiplex receiver.

The single channel receiver.

The continuous tracking receiver.

The multiple satellite receiver.

#104. The height derived from the NAVISTAR GPS is?

Pressure altitude.

Above mean sea level.

Above ground level.

Above the WGS84 elipsoid.

#105. The inclination of a satellite (SV) is?

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

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

The angle between the SV orbit and the Equator.

The angle between the SV orbit and the Polar Place.

#106. Selective availability may be used to degrade the accuracy of the NAVSTAR GPS position, This is achieved by?

Introducing offsets in the broadcast satellites X, Y and Z co-ordinates.

Introducing an offset in the satellite clocks.

Random dithering of the broadcast satellite clock time.

Random dithering of the broadcast satellites X,Y and Z co-ordinates.

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

Laser.

Quartz.

Mechanical.

Atomic.

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

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 synchronising the receiver clock with the SV clock.

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

#109. 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?

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.

Higher frequency for the C/A and P codes.

Higher frequency for the P code only.

#110. The sky search carried out by GNSS receiver?

Is done prior to each fix.

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

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.

Finish