NAV 1 & 2 Flashcards
Characteristics of Celestial navigation
Sextant and Chronometer
Examples of radio navigation aids
NDB, VOR, DME, ILS
Characteristics of INS
Inertial navigation, useful when no radio source but must be calibrated at the start
Characteristics of GNSS
Global navigation satellite systems. All weather moving maps
Shape of the earth
Oblate Spheroid
What direction does the earth rotate
Anti-clockwise through the north/south pole
How long is a solar day
86400 seconds
How many time zones
24, each 15 degrees
What is earths tilt
23.5 degrees, creates seasons
How is a solar day defined
Time between solar noon at the local meridian (when the sun is directly overhead at noon)
What is the prime meridian
The meridian line running through Greenwich, which gives GMT
What is UTC
Coordinated Universal Time. Time reference for aviation
When is morning civil twilight
When the geometric centre of the sun is 6 degrees below the horizon, end at sunrise
When is evening civil twilight
When the geometric centre of the sun is set and ends 6 degrees below the horizon
What is the maximum angular distance from the equator for latitude
90 degrees + or -
What is the maximum angular distance from the equator for longitude
180 degrees + or -
What is the standard for cartography and satellite navigation
World Geodetic System WGS84 from 1984, revised in 2004
On a grid system what is the horizontal axis labelled
Eastings
On a grid system what is the vertical axis labelled
Northings
What is the anti-meridian
180 degrees east/west. AKA international Date Line
What is direction
Heading from one point to another in degrees
What is distance
The shortest path (typically) between two points on earth
How many meters in 1 nautical mile
1852m
How many minutes of latitude in 1nm
1 degree
How many nautical miles in 1 degree of latitude
60nm
What are great circles
Shortest path between two points on the surface of the Earth. Centre of the circle must pass through the centre of the earth. Equator and both prime and anti meridian are great circles
What are small circles
Circle drawn on the surface of the earth that does not pass through the centre of the earth. If it isn’t a great circle then must be a small circle
At what angle does a rhumb line cut the meridians it crosses
It cuts them all at the same angle so on a flat map it would be on a straight line
Do you need to change headings when following a great circle route
Yes constantly, so can set up a series of rhumb line routes
What is true north
True direction of geographic north pole
What is magnetic north
Free floating magnetic compass points to magnetic north
What is Compass north
Magnetic north but under the influence of both the earths magnetic field as well as other magnetic fields in the vicinity
How do you convert a true heading to a magnetic heading
Add/subtract the variation. West is best, add. East is least, subtract. Variation magnetic is key.
How do you convert a magnetic heading to a compass heading
Add/subtract the Deviation. West is best, add. East is least, subtract. Deviation compass is key
What is magnetic inclination
Magnets dip trying to align to the magnetic field. Pointing east west at the equator and north south at the poles hence compass needle may be weighted
What is an Isogonal
Lines on a map giving the magnetic variation for a specific area
How do you convert a true heading to a compass heading?
Add or subtract both the variation and deviation. West is best so add, east is least so subtract
What is true track
Direction of intended flight measured in degrees clockwise from true north by reference to a meridian
What is a reciprocal track
Track of the aircraft plus 180 degrees
