NAV Flashcards
Standard ICAO model for “moder jord”
WGS 84
World Geodetic system 1984
WGS 84
Standard ICAO model for “moder jord”
World Geodetic system 1984
Cardinal headings
North, South, East and West
Intercardinal headings
North-east, North-west, South-east, South-west
Distance between the Equator and either pole
10.000 km
Circumference of the earth in km and NM
40.000km and 21.600 NM
The shape of the earth
Oblate Spheroid - a sphere which is slightly flattened at its poles.
1 NM =
1 bueminut
Direction skrives altid i x decimaler?
Undtagelsen?
3 decimaler, med undtagelse af RWY direction (Mag)
Hvordan regnes reciprocal directions?
Mindre end 180 C = +200 -20
Mere end 180 C = -200 + 20
Reciprocal direction of 135 C
135+200 = 335
335-20 = 315 C
Reciprocal direction of 017 C
017+200 = 217
217-20 = 197 C
Reciprocal direction of 195 C
195-200 = -005
-005+20 = 015 C
Reciprocal direction of 255 C
255-200 = 055
055+20 = 075 C
The Great Circle
A circle on the surface of the earth whose centre and radius are those of the earth itself.
En cirkel hvis plan går gennem jordens centrum og deler jorden i 2 lige store dele.
Equator
The Great Circle whose plane is at 90 C to the axis of rotation of the earth.
Den storcirkel, hvis plan går gennem jordens centrum og står vinkelret på jordens rotaionsakse.
Parallels of latitude
A small circles on the surface of the earth, whose planes are parallel to the equator.
Cirkler på jordens overflade, hvis plan er parallel med ækvators.
Hvad indikerer parallels of latitude?
En position nord eller syd for ækvator.
Latitude
The latitude of any point is the arc measured along the meridian through the point from the equator to the point.
How is latitude expressed?
In degrees, minutes and seconds and annotated N or S.
Eg. 56*17’51” N or 561751N
Meridians
Semi-Great circles joining the south and north poles.
Every Great Circle passing through the poles forms a meridian and its anti-meridian.
Prime Meridian
The meridian passing through Greenwich.
It’s the reference point for the 0 degree line of the longitude.
All points on the meridian will have the fixed value of 0 degrees E.
The meridian passing through Greenwich
Prime Meridian
Small circle
A circle on the surface of the earth whose centre and radius are not those of the earth.
Longitude
The longitude of any point is the shorter distance in the arc along the equator, between the Prime meridian and the meridian through the point.
Annotated E or W
eg. 009*07’29” E or 0090729E
Graticule
Latitude+Longitude
Null Island
Where the equator and prime meridian cross (0 degrees N, 0 degrees E)
Decimal minutter til grader
For at få i grader /60
(fjern 0, før)
fx. 45 grader, 12’ = 12/60 = 0,2
derfor 45,2 grader
60 grader og 15’ til grader
15/60 = 0,25
derfor 60,25 grader
45,2 grader til decimal minutter
0,2*60 = 12
derfor 45 grader og 12’
Sekunder til decimalminutter
Decimal sek. = 0,x *60
Grader til decimal min.
For at få i decimal min. *60
fx. 60,25 grader = 0,25*60 = 15
derfor 60 grader, 15’
Sekunder til decimal min.
/60
fx. 32’15’’ = 15/60 = 0,25
derfor 32,25’
Decimal min. til sekunder
0,xx60
fx. 64,25’ = 0,2560 = 15
derfor 64’15”
Regneregler for udregning af difference in longitude
W-W fx. (100W - 80W = 20)
E+W fx. (020E+010W = 30)
Hvis de to gradetal giver mere end 180 fratrækkes 360 fra det totale , fordi vi er interesseret i at finde den korteste afstand, trækker vi 360 fra.
fx. (163E+152W)-360 = 45 grader
Rhumb Line
A regularly curved line on the surface of the earth which cuts all meridians at the same angle.
(A line of constant direction, konstant track)
Is Equator a Great circle?
Yes
1 IN in cm
2,54 cm