7 Navigation Theory Flashcards
The Earth rotates in a(n) _________ direction when looking onto the N.Pole
Anti-Clockwise
Latitude lines are ________ to the EQUATOR
PARALLEL
Longitude lines are ________ to the EQUATOR
PERPENDICULAR
The EQUATOR is a line of L___tude
LATITUDE
The Greenwich MERIDIAN is a line of L___tude
LONGITUDE
Lat and Long is denoted in ___es, _____s and ______s
DEGREES
MINUTES
SECONDS
What is a GREAT CIRCLE?
- A circle on the surface of a sphere who’s plane passes through the centre of the Earth.
- The shortest distance between two points on the surface of a sphere.
The Equator is a GREAT CIRCLE
What is a SMALL CIRCLE?
- A circle on the surface of a sphere who’s plane DOES NOT pass through the centre of the Earth.
- All circles (other than GREAT CIRCLES) are small circles.
MERIDIANS are aligned /
MERIDIAN - N/S
PARALLELS OF LATITUDE are aligned /
PARALLELS OF LATITUDE - E/W
What is a RHUMB LINE?
A line on the Earths surface that crosses MERIDANS at a constant angle.
Describe CONVERGENCE
As MERIDIANS move away from the EQUATOR they are no longer parallel and distance between them will reduce.
Lines of L___tude are ONLY parallel at the EQUATOR
LONGITUDE
1 nm is equivalent to _.__ statute miles, or _.__ km
1 nm = 1.15 statute miles
1 nm = 1.85 km
Measuring angles on the Earth is done with the ________ system
SEXAGESIMAL system
List the units of measurement in the SEXAGESIMAL system
DEGREES
MINUTES
SECONDS
A CIRCLE is divided into ___ degrees.
1 circle = 360 degrees
A degree is divided into __ minutes.
1 deg = 60 minutes
A minute is divided into __ seconds.
1 min = 60 seconds
1 nm equates to approx. _ minute of latitude
1 minute
60 nm equates to approx. _ degree(s) of latitude
1 degree
Nautical miles are an ANGULAR/DISTANCE measurement? (Choose one)
ANGULAR
Taken from the centre of the earth.
1 nm on the surface of the Earth equals 1 nm for an aircraft or a satellite in space.
Name the 3 standard units for speed.
kt - Knots
mph - Miles per hour
kph - Kilometres per hour
What are the advantages of using True North over Magnetic?
- Does not change with time
- Basis of most maps and charts
TRUE or FALSE?
Mag North and True North are in the same place?
FALSE
Converting true track to mag direction
Variation East, Magnetic _____
Variation West, Magnetic _____
Variation East, Magnetic LEAST
Variation West, Magnetic BEST
Determine Mag Track
True track = 130
Variation = 15E
Variation EAST, Magnetic LEAST
True - Var = Mag
130(T) - 15E = 115(M)
Determine Mag Track
True track = 060
Variation = 15W
Variation WEST, Magnetic BEST
True + Var = Mag
060(T) + 15W = 075(M)
Determine Mag Track
True track = 285
Variation = 5E
Variation EAST, Magnetic LEAST
True - Var = Mag
285(T) - 5E = 280(M)
Determine Mag Track
True track = 220
Variation = 10W
Variation WEST, Magnetic BEST
True + Var = Mag
220(T) + 10W = 230(M)
Beacons use MAG or TRUE bearings?
MAGNETIC
With respect to magnetic fields. What are isogonals?
ISOGONALS are lines of equal magnetic variation.
What is a GEOID?
The zero surface of the Earth defined by the deviation and variation of the Earth’s gravity.
What is a SPHEROID/ELLIPSOID?
A smooth representation of the Earth’s oblate spheroidal shape.
What is a SPHERE?
Come on. You know this one!
List the 3 different models that can be used to model the Earth’s shape
GEOID
SPHEROID/ELLIPSOID
SPHERE
Name the 2 types of Map Projections
Perspective
Non-Perspective
List the 3 types of PERSPECTIVE projection
- AZIMUTHAL
- CYLINDRICAL
- CONICAL
Due to distortion of a the Earth’s surface on charts, the scale can ____ be constant over the entire projection.
NEVER
To overcome the impossibility of a constant scale on map projections. We commonly use a _______ scale.
GRADUATED scale
Charts that represent bearings accurately are known as ________ Projections.
CONFROMAL Projections
PERSPECTIVE projections are also known as as ________ Projections.
TRUE (geometric) projections
NON-PERSPECTIVE projections are also known as as ________ Projections.
MATHEMATICAL projections
Moving LATERALLY or TRANSVERSALLY refers to movement in the - direction.
E-W direction
Latitude varies between ___ deg and ___ deg.
-90deg and +90deg
The APEX angle of a conical projection equals _ times the angle of latitude of the point of tangency.
2 times the angle of latitude of the point of tangency.
How many types of ‘Standard Parallel’ projection are there?
4
Name the 4 types of ‘Standard Parallel’ projection.
- Conical ONE Standard Parallel
- Conical TWO Standard Parallel
- Cylindrical ONE Standard Parallel
- Cylindrical TWO Standard Parallel
The 1:500,000 LOW FLYING CHART is a ____ ______ chart. (Type of conical projection)
LAMBERT CONFORMAL
AZIMUTHAL projections are best suited fur use in ____ ______ regions.
POLAR/NEAR POLAR
What type of projection that when a straight line is plotted on, will give a RHUMB line?
Mercator projection
A _____/_____ Mercator projection is most commnly used when travelling on Great Circle routes and those that cover considerable distance.
PLANE/OBLIQUE Mercator Projection
List the 4 grid ref systems described in the MAGS lecture
BNG - British National Grid
UTM - Universal Transverse Mercator
UPS - Universal Polar Stereographic
GEOREF - Geographic Reference
Every projection has a ….. (3)
- Central Meridian
- Central Parallel
- Natural Origin
Why might we want to shift the Natural Origin?
To avoid negative coordinates or extremely large coordinate values
Shifts in the grid systems are known as FALSE ______ and FALSE ________
False EASTINGS and False NORTHINGS
In the BNG system the box marked with ‘A’ is located where?
TOP LEFT
Grids are always read ____ings and then _____ings
EASTings then NORTHings
UTM grid system has ______ along the bottom and _____ up the side.
NUMBERS on bottom. LETTERS up side.
What does UTM stand for?
Universal Transverse Mercator
What does UPS stand for?
Universal Polar Stereographic
UPS grid system is used in the _____ regions
POLAR
What does MGRS stand for? (Grids)
MILITARY GRID REFERENCE SYSTEM
How is a MGRS (Mil Grid Ref Sys) given? (Describe each component)
Grid Zone Designation (eg 30U)
100km square identifier (eg WV)
Easting (as accurate as needs be)
Northing (as accurate as needs be)
30UWV2975 - Guernsey Airport
The more Eastings and Northings included the more accurate your reference will be.
What does GEOREF stand for?
GEOGRAPHIC REFERENCE
In the GEOREF system how many Longitude ones and how many Latitude bands are there?
24 LONG zones
12 LAT bands
15deg section used for each
How is a GEOREF (Geographic Ref) given? (Describe each component)
- Four letters identify a one degree quadrangle (eg MKPG)
- Minutes of Longitude (eg 12)
- Minutes of Latitude (eg 04)
MKPG 1204 - Salisbury Cathedral
Name the datum that is commonly used in the UK
WGS 84
List the different types of year (4)
‘Standard’ year - Time for earth to orbit sun.
Sidereal - Time for earth to orbit sun against a fixed star.
Tropical - Time between two succesive Vernal Equinoxes (Spring equinox) 365.25 days
Civil - Calendar Year or Gregorian 365 days
Name the different types of day (2)
Apparent Solar Day - Time interval between successive returns to the local meridian.
Mean Solar Day - Average length of Apparent Solar Days observed over a period of years.
How many minutes (time) does 1 degree of longitude represent?
1 degree of longitude = 4 minutes
LMT varies with the observer’s longitude. If you are E you _____ and for W you ______.
E ADD
W SUBTRACT
Time zones are denoted by ______ in zone charts.
LETTERS
LMT at 12deg W = 03.10.00 on 2 Aug
What is the LMT at 33deg E?
Change in long 45deg E = +180min = +3hr
LMT at 33deg E = 06.10.00 2 Aug
LMT at 46deg E = 09.40.00 on 2 Aug
What is the LMT at 110deg W?
Change in long 156deg W = -624min = -10hr 24min
LMT at 110deg W =
-00.44.00 2 Aug = 23.16.00 1 Aug
LMT at 10deg W = 22.40.00 on 2 Aug
What is the LMT at 80deg E?
Change in long 90deg W = +360min = +6hr
LMT at 80deg E = 04.40.00 3 Aug
Find LMT at Long 26deg E when UTC is 10.30.00 on 2 Aug
UTC = 10.30.00 on 2 Aug
26deg E = +104min = +1hr44min
LMT = 12.14.00 2 Aug
Find LMT at Long 120deg E when UTC is 19.32.00 and Greenwich Date (GD) is 2 Aug
UTC = 19.32.00 2 Aug
120deg E = +480min = +8hr
LMT = 27.32.00 2 Aug = 03.32.00 3 Aug
A ship at Long 62deg W shows zone time of 1500 hours Q 7 Dec.
What is the UTC?
62/15 = 4.1 = 4 (rounded)
1500 + 4 hrs = 1900 7 Dec
How many different twilights are defined?
3
Name the 3 different twilights that are defined. (inc. deg below horizon)
Civil - Up to 6deg below horizon
Nautical - Up to 12deg below horizon
Astronomical - Up to 18deg below horizon
Define the 3 different twilights
Civil - Up to 6deg below horizon. Everyday task just possible without artificial lighting.
Nautical - Up to 12deg below horizon. Outlines still visible, bright stars visible to Mk1 eyeball.
Astronomical - Up to 18deg below horizon. All except the faintest stars visible.
What factors will affect duration and time of twilight? (4)
Observers Latitude
Suns declination
Altitude
For the purposes of night flying, ‘night’ is defined as the time between end of ___ and the beginning of ___
end of Evening Civil Twilight
beginning of Morning Civil Twilight
How does ATC define night flying?
Between 30 mins after sunset and 30 mins before sunrise.
What does BNG (grid system) stand for?
British National Grid
The British National Grid is split into __ ___km x ___km squares
The British National Grid is split into 25 500km x 500km squares
Each square in the BNG (British National Grid) system is assigned a ______ but omits ‘_’.
Each square in the BNG (British National Grid) system is assigned a LETTER but omits ‘I’.
The squares denoted by the letter ‘A’ in the BNG (British National Grid) system can be found in what square?
Top Left
Each 500km x 500km square in the BNG (British National Grid) system is further broken down into …..
100km x 100km
Which can then be broken down further as required until the appropriate scale is obtained
What does UTM stand for?
Universal Transverse Mercator
UTM grid system has ______ along the bottom and _____ up the side.
NUMBERS on bottom. LETTERS up side.
In the UTM grid system the numbered grid zones along the bottom each represent _degs of longitude
6degs of longitude
In the UTM grid system the lettered grid zones up the side each represent _degs of latitude
8degs
The UTM grid system extends from __deg S to __deg N.
80deg S to 84 deg N
In the UTM grid system the each large Grid Zone Designation Area is further broken down to ___km x ___km squares denoted by _ ______
…broken down to100km x 100km squares denoted by 2 LETTERS.
The GEOREF grid system has ______ along the bottom and _____ up the side.
LETTERS along the bottom. LETTERS up side.
In the GEOREF grid system the first half of the provided numbers refers to what?
Minutes of Longitude
MKPG 12250386 has Lon. of 12.25 minutes (NOTE the is a decimal and does not represent 25 seconds)
In the GEOREF grid system the second half of the provided numbers refers to what?
Minutes of Latitude
MKPG 12250386 has Lat. of 03.86 minutes (NOTE the is a decimal and does not represent 25 seconds)
What is the time difference between a Sidereal and Apparent Solar day?
4 mins
How long is the Equator in Nm?
60x360 = 21,600 Nm
Definition of TRACK
Direction of the path of an a/c over the ground
Definition of HEADING
Direction in which the longitudinal axis of the a/c is pointing
Definition of DRIFT
The angle between the heading and track of the a/c
Definition of a RELATIVE BEARING
Direction of feature FROM a/c.
Definition of a TRUE BEARING
True direction of the line joining the feature to the a/c.
Definition of MAGNETIC BEARING
The Magnetic direction of the line joining the feature to the a/c
Calibrated Airspeed (CAS) is ___ corrected for inaccuracies in the ASI
IAS corrected for inaccuracies
Equivalent Airspeed (EAS) is ___ corrected for inaccuracies in the ASI
CAS corrected for compressibility
What is True Airspeed (TAS)?
The speed of the a/c relative to the air mass through which it is moving.
