Aircraft position calculation
Thread Starter
Joined: Mar 2004
Posts: 3
Likes: 0
From: Indonesia
Aircraft position calculation
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.
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.
Joined: Mar 2000
Posts: 811
Likes: 0
From: Australia
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!
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!
Joined: Dec 1998
Posts: 4,282
Likes: 6
From: Escapee from Ultima Thule
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????"
3. Press other buttons to change display to Bearing/Distance from waypoint.
4. Look at altimeter.
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????"
3. Press other buttons to change display to Bearing/Distance from waypoint.
4. Look at altimeter.
