OGRAD 10.01 - Satellite Assisted Navigation ( ATPL Only)

Results

Q1. In relation to the NAVSTAR/GPS satellite navigation system, what is involved in the differential technique (D-GPS)?

Signals from satellites are received by 2 different antennas which are located a fixed distance apart. This enables a suitable receiver on the aircraft to recognise and correct for multipath errors

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

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

Q2. Which of the following statements about the accuracy that can be obtained with the differential technique (D-GPS) of the satellite navigation system NAVSTAR/GPS is correct?

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

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

Only D-GPS allows position fixes accurate enough for 'Non Precision Approaches'

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

Q3. 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 RAIM-function of the GPS receiver must be able to monitor all prescribed navigation systems

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

The prescribed IFR-equipment must be installed and operational

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

The prescribed IFR-equipment must be installed and operational

Q4. Differential GPS (DGPS)

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

Is used to differentiate between the signals from different satellites

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

Means to find the difference between a DR position produced by the navigation (between the GPS position and the real position) computer and the GPS position

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

Q5. Which satellite NAVSTAR/GPS navigation system error(s) are corrected for by the differential (D-GPS) technique?

Ephemeris

Clock; receiver noise

Clock; Selective Availability (SA)

Receiver noise

Clock; Selective Availability (SA)

Q6. 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?

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

It causes multipath propagation

It may prevent the reception of signals

It has no influence because high frequency signals are unaffected

It may prevent the reception of signals

Q7. Which one of the following is an advantages of a multi-sensor system using inputs from a global navigation satellite system (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 average position calculated from data provided by both systems increases overall accuracy

The GNSS can be used to update a drifting INS

Q8. 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 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

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