Projects:EASA PPL/Navigation

From Wiki


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


  • 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


  • 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


  • 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


  • Phase difference


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


  • 2 modes, 4096 codes each