# 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