Projects:EASA PPL/Navigation: Difference between revisions
(Created page with "* Units: ** 1NM = 1852m ** 1NM = 6080ft * 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 * Seasons: ** Due to inclination of the polar axis with the ecliptic plane *Time: **Twilight duration: longer at high latitudes *Magnetic: **CDMV...") |
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* | == 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: | * Seasons: | ||
** Due to inclination of the polar axis with the ecliptic plane | ** Due to inclination of the polar axis with the ecliptic plane | ||
*Time: | *Time: | ||
**Twilight duration: longer at high latitudes | **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 |
Latest revision as of 17:45, 22 January 2023
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