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RADNAV-RH-CHAPTER13-DOPPLER
1.
An apparent increase in the transmitted frequency which is proportional to the transmitter velocity will occur when:
a) the transmitter moves away from the receiver
b) the transmitter moves towards the receiver
c) the receiver moves towards the transmitter
d) both transmitter and receiver move towards each other
2.
Due to Doppler effect an apparent decrase in the transmitted frequency, which is proportional to the transmitters velocity, will occur when:
a) the transmitter and receiver move towards each other
b) the transmitter moves away from the receiver
c) the transmitter moves toward the receiver
d) both transmitter and receiver move away from each other
3.
The Doppler Navigation System is based on:
a) Doppler VOR (DVOR) Navigation System
b) radio waves refraction in the ionosphere
c) radar principles using frequency shift
d) phase comparison from ground station transmissions
4.
A LOP is inaccurate and may be ambiguous:
a) in the vicinity of the base line bisector
b) in the vicinity of the base line extensions
c) at extreme ground wave range
d) at night due to sky wave effect
5.
In day to day use the greatest cause of error in Doppler is:
a) input error
b) sea movement error
c) weight error
d) pitch error
6.
Updating Doppler is undertaken when:
a) the co-ordinates are reset to revise the position base on alternative
information
b) a new database is loaded
c) the equipment is re-initialised with the data and time, and the atomic clock
is actuated
d) all of the above
7.
After a long period in memory, Doppler:
a) falls back to INS
b) requires updating
c) should be switched to manual
d) will have wandered more over land than over sea
8.
Sea bias error:
a) is due to the movement of the seea and can be partially corrected by the land/sea switch
b) is due to the movement of the sea and is not affected by the land/sea switch
c) is due to a change in Doppler shift over water and is not affected by the land/sea switch
d) is due to a change in Doppler shift over water and is partially corrected by the land/sea switch
9.
With regard to Doppler navigation system:
a) updating is the process of entering co-ordinates after taking a fix
b) updating can be achieved using VOR/DME fix
c) updating must be carried out as soon as possible after a prolonged period in memory
d) all of the above are correct
10.
A radio facility transmits on a wavelength of 2,22 cm. The facility could be a:
a) radio altimeter
b) Doppler
c) LORAN-C
d) DME
11.
The 4-beam moving Janus array aligns with the aircraft centre line by:
a) rotating the array towards the beams with the smallest Doppler shift
b) rotating the array until matched pairs of beams receive the same difference in Doppler shift
c) measuring the drift and rotating the array by the same amount
d) all of the above
12.
Which of the following statements is correct when considering a Doppler navigation system?
a) aerial misalignment will produce an error to drift angle
b) sea bias can be reduced by ujsing a gyro stabilised aerial array
c) sea movement error produces higher frequency, and thus ground speed as indicated will be too low
d) all of the above
13.
Doppler may unlock over:
a) shallow fast running water
b) a calm sea
c) a desert surface
d) ice
14.
What frequencies are allocated to Doppler Navigation systems?
a) 8.8 Hz and 13.3 Hz
b) 8.8 KHz and 13.3 KHz
c) 8.8 MHz and 13.3 MHz
d) 8.8 GHz and 13.3 GHz
15.
The largest error and source of error on a Doppler derived position is:
a) Cross track due to compass error
b) Along track due to TAS computation error
c) Cross track due to errors in drift measurement
d) Cross track due to error in drift bias
16.
Which of the following statements is TRUE in respect of Doppler?
a) The lower the vehicle speed, the higher the transmission frequency used
b) The higher the vehicle speed, the higher the transmission frequency used
c) Aerials are stabilised to reduce pitching errors
d) Aerials are stabilised to reduce climb errors
17.
When a transmitter is moving towards a receiver, the correct description of Doppler Effect is:
a) There is a decrease in apparent wavelength which is dependent on the transmitter velocity
b) There is a decrease in apparent wavelength which is independent of the
transmitter velocity
c) There is a increase in apparent wavelength which is dependent on the
transmitter velocity
d) There is an increase in apparent wavelength which is independent of the
transmitter velocity
18.
Doppler navigation systems use ___ to determine aircraft ground speed and drift:
a) DVOR
b) Phase comparison of signals from ground stations
c) Frequency shift in signals reflected from the ground
d) DME range measurement
19.
In which navigation system does the master station transmit a continuous string of pulses on a frequency close to 100 KHz?
a) Loran C
b) GPS
c) Decca
d) Doppler
20.
Which of the following statements concerning LORAN-C is correct?
a) It is a hyperbolic navigation system that works on the principle of range measurement by phase comparison
b) It is a navigation system based on secondary radar principles; position lines are obtained in sequence from up to eight ground stations
c) It is a hyperbolic navigation system that works on the principle of differential range by pulse technique
d) It is a navigation system based on simultaneous ranges being received from a minimum of four ground stations
21.
Loran C coverage is:
a) global
b) confined to certain limited areas of the world
c) unrestricted between latitudes 80oN and 70oS
d) unrestricted over the oceans and adjacent coastlines but limited over the
major continental land masses
22.
Which of the following correctly gives the principle of operation of the Loran C navigation system?
a) Differential range by phase comparison
b) Frequency shift between synchronised transmissions
c) Differential range by pulse technique
d) Phase comparison between synchronised transmissions
23.
The principle of operation of LORAN C is:
a) differential range by phase comparison
b) differential range by pulse technique
c) range by pulse technique
d) range by phase comparison
24.
The frequencies used by LORAN C are:
a) 70 – 130 KHz
b) 90 – 110 KHz
c) 108 – 112 MHz
d) 190 – 1750 KHz
25.
LORAN C is available:
a) globally
b) in oceanic areas
c) in continental areas
d) in designated areas
26.
Which statement is most correct?
a) Loran C creates hyperbolic position lines based on differential range by pulse technique
b) Loran C creates hyperbolic lines based on a low sweep rate frequency
modulated continuous wave
c) Loran C creates hyperbolic lines based on an atomic time standard
d) Loran C creates elliptical lines based on differential range by Doppler
27.
Which of the following frequency-bands is used by the Loran C navigation system?
a) 10.2 – 13.6 KHz
b) 1750 – 1950 KHz
c) 90 – 110 KHz
d) 978 – 1213 MHz
28.
The accuracy of Loran is given as:
a) ±½ km on 95% of occasions between 900 km and 1000 km over the sea
b) ±1 nm on 95% of occasions between 900 nm and 1000 nm over the sea
c) ±1 km on 95% of occasions between 900 km and 1000 km over the sea
d) ±½ nm on 95% of occasions between 900 nm and 1000 nm over the sea
29.
Loran C is a navigation system which uses:
a) differential range measurements
b) rho/theta measurements
c) pseudo range measurements
d) slant range measurements
30.
Loran C operates at a frequency of:
a) 100 MHz
b) 100 KHz
c) 1000 KHz
d) 1000 MHz
31.
A Loran C chain is designated according to:
a) a Group Repetition Interval
b) a colour coding
c) a frequency
d) a chain sequential number
32.
A Loran C chain is designated according to:
a) behind the master station
b) behind the Slave station
c) on any base line extension
d) along the base line bisector
33.
On a Loran C station pair, the lowest value of propagation delay time difference will be found:
a) on the base line bisector
b) on the slave base line extension
c) on the master base line extension
d) at various points depending on the particular pair
34.
Loran is available for use:
a) in North and south America
b) worldwide, pole to pole
c) North America, North Atlantic, parts of Europe and the Mediterranean
d) every where except the old eastern bloc
35.
Loran position lines/fixes in the coverage area are:
a) available both day and night
b) unreliable at down and dusk
c) unreliable at night
d) unreliable along the baseline
36.
The time difference is measured in a Loran receiver by:
a) crystal oscillation
b) indexing
c) phase comparison
d) phase measurement
37.
A hyperbola is a line of surface:
a) of constant range from two fixed points
b) on which all points have a constant range difference from each other
c) on which all points have the same difference or range from two fixed points
d) which intersects the base line at 90o in all planes except the vertical
38.
Propagation error is due to:
a) coastal refraction
b) sky wave effect
c) super refraction
d) differences in surface conductivity
39.
LORAN C:
a) is an hyperbolic navigation system
b) operates using red, green and purple lanes
c) sends coded radio transmissions from satellites in close Earth orbit
d) utilises very high frequency radio transmissions
40.
LORAN C operates using ___ which one ___ as master and the others arranged around it and known as ___ secondary (slave) ___
a) networks or chains of stations; stations; W, X, Y and Z stations
b) satellites; satellite; W, X, Y and Z; satellites
c) networks or chains of stations; station; red, green and purple; stations
d) Satellites; Satellites; X, Y and Z; satellites
41.
In Loran C, if range difference is determined by using phase difference measurements on the carrier wave, the accuracy of these measurements is no better than:
a) ±10 µs
b) ±1 µs
c) ±50 µs
d) ±5 µs
42.
The master and slave stations of a hyperbolic navigation system are between 50 to 100 nm apart. What factor will govern the maximum fixing accuracy:
a) The power output of the transmitters
b) The maximum in-phase differences
c) the cut of the position lines
d) The lanes which are based on the positions of zero phase difference
43.
A hyperbolic position line joins all points of:
a) equal range between two ground stations
b) zero phase difference between two signals
c) equal difference in range between two stations
d) equal time taken by two simultaneous transmissions
44.
In a hyperbolic navigation system accuracy is greatest:
a) along the right bisector of the baseline
b) along the baseline
c) along the baseline extension
d) within a 30 nm radius of either station
45.
The principle of operation of DECCA is:
a) identification of equal time differences from signals with coded group repetition intervals (GRI)
b) comparison of phase shift
c) analysis of time referenced scanning beam
d) analysis of time of arrival and time difference by phase comparison
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