Radio Navigation Flashcards

(44 cards)

1
Q

Cycle

A

Interval between any 2 points measuring the completion of a single wave movement

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2
Q

Diffraction

A

Bending which occurs when a wave grazes the edge of a solid object through which it cannot pass

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3
Q

Attenuation

A
  • Loss of wave as it travels through a medium
  • Example is driving away from a radio station
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4
Q

Ionosphere

A
  • Layer of rarified ionized gas believed to be caused by ultra-violet solar radiation
  • Ranges from 60 to 200 miles above the earth and vary according to time of day, season, and latitude
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5
Q

Ground Waves

A
  • Parts of the transmitted radiation that follows the surface of the earth
  • Not subject to ionospheric interference or weather
  • Suffers from surface attenuation proportional to the frequency
  • Lower frequencies = less attenuation
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6
Q

Space Waves

A

Parts of the transmitted radiation that travel directly into space

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7
Q

Sky Waves

A
  • Parts of the transmitted radiation that is reflected or refracted from the ionosphere
  • Continues to reflect between the earth and sky until completely attenuated
  • Skip Zone
  • The distance between the end of the useful ground wave and the point where the sky wave is returned to earth
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8
Q

Ground Waves Radio Frequency Categories

A
  • Very Low Frequency (VLF)
  • Low Frequency (LF)
  • Medium Frequency (MF)
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9
Q

Sky Waves Radio Frequency Categories

A

High Frequency (HF)

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10
Q

Space Waves Radio Frequency Categories

A
  • Very High Frequency (VHF)
  • Ultra High Frequency (UHF)
  • Super High Frequency (SHF)
  • Extremely High Frequency (EHF)
  • Line of sigh transmission
  • Signals not affected by time of day, season, precipitation, or atmospheric conditions
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11
Q

Characteristics of VHF Signals

A
  • Do not follow the curvature of the earth
  • Do not bend around obstructions
  • Primarily space waves
  • Reception is limited by line of sight
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12
Q

VHF Omnidirectional Range (VOR)

A
  • Frequency Range is 108.1-117.95 MHz (VHF)
  • 3 letter morse code identifier
  • Transmits 2 signals, a reference phase and variable phase
  • Beacon rotates at 6 RPM, green light flashes the instant the beacon passes magnetic north
  • Actual VOR does this electronically
  • Beams emitted by VOR called radials
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13
Q

VOR components - Omni Bearing Selector (OBS)

A

Selects Desired Radial

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14
Q

VOR components - Course Deviation Indicator (CDI)

A
  • Shows aircraft position relative to selected radial
  • Each dots equals 2 degrees up to a maximum of 10 degrees either side of radial
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15
Q

VOR components - Sense Indicator (TO/FROM)

A

Indicates whether the aircraft is the TO or FROM side of the VOR

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16
Q

VOR interpretation

A
  • VOR interpretations are dependant only on the position relative to the selected radial
  • Rule of thumb is that in order to properly navigate, the heading and the OBS must agree or else reverse sensing will occur
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17
Q

VOR Homing (Direct to VOR site)

A
  • Tune to proper frequency
  • Confirm proper morse code using IDENT
  • Rotate OBS knob to obtain a TO indication
  • Rotate the OBS until the CDI centers with a TO indication
  • Fly the heading under the OBS indicator
  • Adjust heading as needed to keep CDI centered
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18
Q

VOR Position Fixing (Finding exact location using 2 VOR’s)

A
  • Tune and Identify VOR-A
  • Centre the needle with a FROM indication, OBS is radial the aircraft is on
  • Draw a line on map from centre of VOR compass rose out through the indicated radial
  • Repeat for VOR-B
  • Aircraft’s position is where lines intersect
19
Q

VOR Serviceability Checks - VOR Test Facility (VOT)

A
  • Sends out one radial, 360º
  • CDI centres 360º FROM and 180º TO
  • CDI must centre within 4º
20
Q

VOR Serviceability Checks - VOR Check Point

A

CDI must centre within 4º

21
Q

VOR Serviceability Checks - Dual VOR

A
  • Same radial on two VOR’s
  • CDI must agree within 4º
22
Q

VOR Serviceability Checks - Airborne VOR Check

A

Over a known fix or landcmark CDI must agree within 6º

23
Q

VOR Facilities

A
  • Stand Alone VOR is radial information only
  • VOR and co-located DME
  • TACAN is similar to a VOR but uses UHF frequencies and is for military use, always has DME
  • Often a TACAN is co-located with a VOR and is called a VORTAC
24
Q

Automatic Direction Finder (ADF)

A
  • Frequency Range between 190 and 415 kHz and 510-535 kHz (LF/MF)
  • 1,2, or 3 letter Morse code identifier
  • Transmits a single non-directional signal
  • Mostly ground waves and some sky waves
  • Follows curvature of the earth
  • Reception is greater than VHF at low altitudes and over longer distances
25
ADF Principles of Operation
- Works similar to a portable AM radio - A listener holding a radio turns themselves in a circle - Strongest at 0º and 180º, nothing at 90º and 270º - Receiver uses this to identify 2 places the signal could be coming from - Internal electronics resolve the sense and determine the signals actual source in relation to the aircraft - This drives the needle on instrument
26
How to Use The ADF
- Tune desired frequency from the map using ADF radio - Listen to the ident to confirm the correct Morse code identifier - Once identified, return the function switch to ADF position
27
ADF Interpretation
- On the fixed card, 0 represents the nose while 180 represents the tail - Pointer shows the relative bearing TO the station - Basic ADF consists of a fixed card and a bearing indicator needle - Needle always points TO the station - Magnetic Heading plus Relative Bearing equals Magnetic Bearing TO the station
28
ADF Position Fixing (Finding exact location using 2 NDB sites)
- Tune and identify NDB-X - Read the relative bearing of the bearing needle - Use the formula to find the bearing to the station - Calculate the reciprocal bearing to obtain bearing from the station - Draw a straight line from NDB-X on the calculated bearing from the station on a map - Repeat for NDB Y - Aircraft position is where lines intersect
29
ADF Serviceability Checks (Ground Check)
- Identify station and confirm correct relative bearing - Change mode to ANT and confirm correct behaviour of bearing needle - Change mode back to ADF and confirm bearing needle returns promptly to correct bearing - During instrument checks while taxiing, the ADF needle should swing to track the station during turns - Since there are no flags on the ADF, ident should be left on to confirm operation
30
ADF Errors - Night Effect
Radio waves reflected back by ionosphere can signal strength fluctuations, especially just before sunrise and just after sunset
31
ADF Errors - Mountain Effect
High Terrain reflects radio waves
32
ADF Errors - Static Interference
Precipitation causes static interference
33
ADF Errors - Bank Error
Errors based on how the antenna is installed
34
ADF Errors - Quadrantal Error
Angular error caused by metal in the vicinity of the antenna
35
ADF Errors - Coastal Effect
Ground wave bending due to shoreline
36
ADF Errors - Needle Oscillations
Noisy Identification
37
GPS Principles of Operation
- UHF frequency is 1575.42 MHz - Each satellite sends a series of signals - The receiver determines how long it took each signal to reach it - Because the speed of radio waves is known, distance can be determined - Receiver triangulates position, and can determine track and groundspeed - Receiver needs 4 satellites to determine position
38
Distance Measuring Equipment (DME)
- Operates in UHF range - 960-1024 MHz for transmissions - 1025-1150 MHz for replies - Radio signal paired with VHF frequency at TACANs, VORTACs - Aircraft DME automatically functions for whichever VOR frequency is selected
39
DME Limitations
- Slant Range error - Greatest at high altitude close to station
40
Radio Detection And Ranging (RADAR)
- Short pulses of super high frequency radio energy fired from rotating transmitter - Strike aircraft and are reflected back to sender
41
Primary Radar
- Requires no equipment on board - Simply plots reflected radar energy on a screen - Used by ATC to monitor airport and terminal areas
42
Secondary Radar
- Requires a transponder on aircraft - Includes sqwuak code and other information
43
Radio Magnetic Indicator (RMI)
- Electric navigation instrument that combines a magnetic compass with an ADF or VOR - Card of the RMI acts as a gyro-stabilized compass, and shows the magnetic heading the aircraft is flying
44
Electronic Flight Instrument System (EFIS)
- Displays flight data electronically - Normally consists of primary flight display (PFD), multi-function display (MFD), and engine indicating and crew alerting system (EICAS)