Navigation Flashcards
What is variation
The difference between magnetic and true
What is compass deviation
Difference between magnetic and compass north
What is departure
The east west distance along a parallel of latitude
Rhumb line
Tracks with a constant direction between two points on a sphere
Convergency
Change of direction experienced between two points
Doppler effect
Change in frequency of signal due to change in distance between transmitter and receiver
How does INS/IRS find true and magnetic north
True = by being aligned by gyros
Magnetic by applying variation
Ads of INS/IRS
-global
-self contained
-very accurate
-ring laser (short warm up, no real wonder, no real precession, accurate)
Disads of IRS/INS
- Bounded and unbounded errors
- Inherent
What 3 things makes up INS/IRS
- Gyros
- Accelerometers
- Computers/electronics
How many satellites for gps
24 or more from US department
Ads of GPS
-global
-high capacity use
-lots of redundancy
-cornerstone for future
-very accurate
What does differential gps eliminate
- Selective availability
- Ionospheric errors
Two reasons why INS/IRS is more accurate than GPS
- Downgrading on normal GPS
- Only true onboard self contained system
What is RNAV
Onboard area navigation equipment that uses basic VOR/DME, as well as other position sensors
VHF direction finding
Uses communication radio waves to provide bearing info
QUJ, QTE, QDM, QDR
QUJ- true bearing to
QTE- true bearing from
QDM- magnetic bearing to
-QDR- magnetic bearing from
NDB frequency and range equation
200-1750khz
Range = 3 x root (power output)
Issues NDB prone too
- Static
- Mountain affect
- Coastal effect
- Quadrantal error
- Interference
- Night effect
What must NDBs be accurate to
5 degrees
When is BFO used
To ident an NDB when unmodulated carrier waves are used
VOR frequency and range equation
108-118mhz
Range = 1.25 (root H1) + 1.25(root H2)
3 issues prone to VOR
Equipment error
Site error
Propagation error
Localiser coverage
Up to 6000ft
10deg to 25nm
35deg to 17nm
Both either side of centreline
Glide slope distances
10NM, 8deg either side of localiser
Modulation frequency ils
90hz and 150hz
ILS frequency range
108 to 112 MHz
DME basis of operation and range
Onboard interrogator and ground beacon transponder
Range = root (1.5 x aircraft height)
DME accuracy
0.5nm or 3%, whatever is greater
3 modes of transponder
Mode A - aircraft info only
Mode C - aircraft info and altitude
Mode S- everything + data communication ability
Weather radar aerial coverage
90deg L/R
Tilt 15deg
Weather radar colours
Green = light precipitation
Yellow/amber = medium precipitation
Red = heavy
Magenta = extreme
Different picture shapes on weather radar
Finger/hook/Ushape = vertical drafts, hail
Rapid changing shapes = areas of high instability
Isohypse
Line of equal height and barometric pressure
Fastest jet stream
Sub tropical
