Projects:EASA PPL/Navigation

Earth

• Earth tilt angle: 23,44°
• Rhumb line: cutting all meridians at the same angle
• circumference: 21600 NM / 40000km

Sun

• Rise above the horizon: top and low latitude at summer and winter: 66°
• Be at 90° above horizon: 23°
• Civil twilight: sun 6° below horizon (30min before/after sunrise/sunset)
• Seasons:
  • Due to inclination of the polar axis with the ecliptic plane
• Time:
  • Twilight duration: longer at high latitudes

Magnetic

• CDMVT: Compass - Deviation - Magnetic - Variation - True
• Compass check swing: measure the angle between magnetic north and compass north
• Agonic line: positions on line have 0° variation
• Isogonic line: positions on line have same variation
• Aclinic line: zero magnetic dip

Sphere / Latitude / Longitude:

• Latitude: angular distance along meridian from equator to a parallel of the latitude
• Longitude: arc at equator between greenwich meridian and location meridian
• Distance on great circle: diff angle * 60NM = distance NM
• Distance: diff longitude * 60NM * cos latitude = distance NM
• parallels of latitude: = rhumb lines (constant direction)

Direct Mercator

• great circle: curve concave to equator
• rhumb line: straight line
• parallels of latitude: are parallel straight lines unequally spaced
• Meridians: parallel, equally spaced, vertical straight lines

Lambert conformal conic chart:

• convergence of meridians is same as earth convergency at the parallel of origin
• convergency: most accurate at parallel of origin
• scale: quoted scale is correct along the two parallels, correct along a parallel of latitude
• great circles: are curves concave to the parallel of origin
• straight line on lambert chart: is approximately a great circle
• parallels: represented by arcs of concentric circles

GPS

• Minimum satellites: 4 (without RAIM)
• Minimum satellites safe: 6 (with RAIM)
• Orbit: Circular / 12 hours
• Satellites: 6 orbital planes with 4 sats in each plane (Total 24)
• Height above MSL: 20200km / 10900 NM
• RAIM (Receiver Autonomous Integrity Monitoring): verify integrity of navigation data
• Frequency: UHF
• Accuracy: ICAO average 95%: 13m horizontally
• Decrease accuracy: satellite clock, satellite ephemeris, atmospheric propagation
• Civil aviation: L1 coarse acquisition with selected availability (C/A) (1575 MHz, 2 codes)
• Coordinate system: WGS 84 (ellipsoid)
• Segments: control, space, user
• Height: above WGS-84 ellipsoid
• Inclination: angle between orbital plane and equatorial plane
• Orbital plane: inclined 55° to the equatorial plane
• PRN (Pseudo random noise): code to identify satellites
• Navigation message: Almanac data, satellite status

VOR

• Phase difference

DME

• colocated with VOR: DME ident can be heard once every 40s

Transponder

• 2 modes, 4096 codes each