View Full Version : Aircraft position calculation
budipro
9th Mar 2004, 08:23
Hi all,
I have a question here:
How do you calculate an aircraft current position (latitude, longitude, and altitude) based on:
- the aircraft last position (latitude, longitude, and altitude),
- the elapsed time (now - last position time),
- the aircraft speed (knot), and
- the aircraft direction (stated using angle from north)?
Thanks a lot.
*Lancer*
10th Mar 2004, 15:25
It's easy! Just use an IRS :)
It's impossile to calculate altitude using that information unless it remains the same...
Calculating distance from a point is easy (distance = speed x time), but things get tricky very quickly when you want the answer as a Lat/Long. Actual distance (what you can actually work out) between degrees of longitude will vary with latitude... It's not impossible though!
Tinstaafl
11th Mar 2004, 01:24
1. Lay chart on knee
2. Find last two or 3 marked fixes.
3. Extrapolate OR use last known track made good OR use heading + reasonable drift allowance to give line of position
3. Note time.
4. Note last calculated groundspeed OR TAS + reasonable +/- wind adjustment.
5. Use 3. & 4. to calculated distance run.
6. Mark this DR distance along LoP.
7. Read lat. & long. from map.
8. Look at altimeter.
OR
1. Press button on GPS to read current lat. & long.
2. Go "Huh????" :confused:
3. Press other buttons to change display to Bearing/Distance from waypoint.
4. Look at altimeter.
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