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Use GPS To Track Flight Lessons


hccurry
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I plan to start flight lessons soon and would like to take my gps along and to track the routes of my flights and then possibly incorporate them into my topo maps or google earth...has anyone done anything like that? Any suggestions?

Thanks,

HCCURRY

The following works with a Garmin - a similar procedure should be possible with most brands.

 

Firstly - if your GPSr has a barometric altimeter, and the plane is pressurised, you will want to set it to "Fixed Elevation" mode and "Auto-Calibration Off" - otherwise, your altimeter will record your elevation as being the equivalent elevation of the cabin pressure (maybe 2,000 metres maximum or so), so you will lose most of the 3D content.

 

If you are in a non-pressurised aircraft, calibrate your altimeter before you start, and have the barometric altimeter set to "Variable Elevation" with "Auto-Calibration On". Note that there will still be elevation errors due to the Bernoulli Effect (higher air-speed gives lower air pressure) - I can't tell you what impact this will have for elevation records in your aircraft - it will depend on aircraft type, flying speed, etc. You will need to experiment to find out.

 

Set the track-log to record at suitable intervals - I find "Method: Auto" and "Interval: Normal" works well for me.

 

Have your GPSr set up where it will get the best possible satellite signal - on the dash under the windscreen would be a good choice. Record a track-log throughout your flight. Transfer the track log into MapSource, and then select "View | View in Google Earth". Set Google Earth to show vertical exaggeration = 1.0. You should now be able to see your track-log overlaid in 3D on the normal Google Earth imagery.

 

Hope this helps!

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Never done it, but it sounds interesting. I wonder if there's a way to map your movements in 3D, because that would look really cool.

tahoe_gliding_ge.jpg

 

I was thinking more of a 3D block-type of map where you could also see movements in the vertical. Ex: as you look at the track, not only would you see left and right movements, but you would also see the track move up or down as the plane changes altitude.

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Never done it, but it sounds interesting. I wonder if there's a way to map your movements in 3D, because that would look really cool.

tahoe_gliding_ge.jpg

 

I was thinking more of a 3D block-type of map where you could also see movements in the vertical. Ex: as you look at the track, not only would you see left and right movements, but you would also see the track move up or down as the plane changes altitude.

That example is in Google Earth where you can see that if you wanted to, or have a cockpit POV playback of the track.
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I plan to start flight lessons soon and would like to take my gps along and to track the routes of my flights and then possibly incorporate them into my topo maps or google earth...has anyone done anything like that? Any suggestions?

Thanks,

HCCURRY

 

Yes, you can do this and you will probably find it very interesting to look back at.

 

Below is a recent track of mine I did with my Oregon 400t. It was in my pants pocket and didn't always pick up the greatest, but it had good reason not to since part of the time I was inverted (lost sat. reception a couple of times). You can't very well tell it from the picture below but if I zoom in alot on the track I can tell where the maneuvers were done. In this track (2) rolls, (1) loop, a hammerhead, and (3) low level fly-bys were done. Below, you can tell where the hammerhead was done over the river.

Edit: The track below looses alot of it's detail because some of the track is overlaid on top of itself due to being zoomed out to post here.

 

2144160230105013954S500x500Q85.jpg

Edited by eaparks
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I fly hot air balloons for a living and the track recording is precisely why I bought my gps (76CSX). After recording a few flights I found I could load them into GoogleEarth and get the 3D representation of the flight. I capture the GE image and .kmz file and post both to my website so customer can see their flight and also so future customers can see what a flight might be like. I think you'll enjoy recording your flight lessons and being able to look back and learn.

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Note that there will still be elevation errors due to the Bernoulli Effect (higher air-speed gives lower air pressure)

That probably would only apply if the instrument taking the reading is directly subjected to the air moving at high speed, i.e. outside the aircraft. If the GPSr is inside the aircraft then there is no high airspeed around the instrument, and therefore no Bernoulli effect.
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Never done it, but it sounds interesting. I wonder if there's a way to map your movements in 3D, because that would look really cool.

tahoe_gliding_ge.jpg

 

I was thinking more of a 3D block-type of map where you could also see movements in the vertical. Ex: as you look at the track, not only would you see left and right movements, but you would also see the track move up or down as the plane changes altitude.

That example is in Google Earth where you can see that if you wanted to, or have a cockpit POV playback of the track.

 

Is there a special setting on Google Earth that will allow me to view the track overlay?

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Note that there will still be elevation errors due to the Bernoulli Effect (higher air-speed gives lower air pressure)

That probably would only apply if the instrument taking the reading is directly subjected to the air moving at high speed, i.e. outside the aircraft. If the GPSr is inside the aircraft then there is no high airspeed around the instrument, and therefore no Bernoulli effect.

In my experience (in cars), most modern cars seem to be set up such that they have dominant ventilation outlets in an area of low external pressure (e.g. near the C-Pillar) so as to ensure strong ventilation by suction, even if the AC and fan are turned off, all windows closed, etc. The air pressure felt inside the cabin will be dominated by the external air pressure at the dominant air inlet and / or outlet.

 

In my observations, this means the altimeter typically reads about 5 to 10 metres high when travelling at around 100 km/hour. The altimeter reading will instantaneously drop by about 5 or 10 metres when you stop. Opening and closing windows and air vents can change the indicated elevation when travelling at speed, because it can change the dominant ventilation points to an area of higher or lower air pressure.

 

I would expect to see a similar behaviour in an unpressurised aircraft, but I don't have any first-hand experience.

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Note that there will still be elevation errors due to the Bernoulli Effect (higher air-speed gives lower air pressure)

That probably would only apply if the instrument taking the reading is directly subjected to the air moving at high speed, i.e. outside the aircraft. If the GPSr is inside the aircraft then there is no high airspeed around the instrument, and therefore no Bernoulli effect.

In my experience (in cars), most modern cars seem to be set up such that they have dominant ventilation outlets in an area of low external pressure (e.g. near the C-Pillar) so as to ensure strong ventilation by suction, even if the AC and fan are turned off, all windows closed, etc. The air pressure felt inside the cabin will be dominated by the external air pressure at the dominant air inlet and / or outlet.

 

In my observations, this means the altimeter typically reads about 5 to 10 metres high when travelling at around 100 km/hour. The altimeter reading will instantaneously drop by about 5 or 10 metres when you stop. Opening and closing windows and air vents can change the indicated elevation when travelling at speed, because it can change the dominant ventilation points to an area of higher or lower air pressure.

 

I would expect to see a similar behaviour in an unpressurised aircraft, but I don't have any first-hand experience.

Good explanation of your original post. I was thinking you meant that the airspeed outside the aircraft would cause the Bernoulli effect on a GPSr, like the air pressure difference between the top and bottom sections of a wing that create lift.

 

I'm curious now to try this out in a car to see the elevation change at different speeds.

 

I have used my GPSr in commercial (pressurized) airplanes, and often the elevation shows something like 15,000 feet. I think the cabin altitude (pressure) of a typical flight is 8,000 or 9,000 feet, so 15,000 probably couldn't be based on barometric pressure. But neither would 15,000 be based on the GPS signal if the plane is well above 30,000 feet. Never been able to figure out what the 15,000 feet is based on, but it's always interesting just to use the GPS in an airplane to see how fast we're going, where we are, etc.

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I have used my GPSr in commercial (pressurized) airplanes, and often the elevation shows something like 15,000 feet. I think the cabin altitude (pressure) of a typical flight is 8,000 or 9,000 feet, so 15,000 probably couldn't be based on barometric pressure. But neither would 15,000 be based on the GPS signal if the plane is well above 30,000 feet. Never been able to figure out what the 15,000 feet is based on, but it's always interesting just to use the GPS in an airplane to see how fast we're going, where we are, etc.

My altimeter always seems to read about 2,000 metres (6,500 feet) in commercial planes. According to Wikipedia http://en.wikipedia.org/wiki/Cabin_pressurization :

 

"The outflow valve is constantly being positioned to maintain cabin pressure as close to sea level as practical, without exceeding a cabin-to-outside pressure differential of 8.60 psi. At a cruising altitude of 39,000 feet (FL 390), a Boeing 767's cabin will be pressurized to an altitude of 6,900 feet."

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Hmmm. I have data saved from a flight in a small plane with my father. I don't know how to post it, though. It is a couple of Print Screen shots from DeLorme Topo 8 (I use a PN 20) pasted onto a word document. It is pretty slick. It shows speed and elevation changes as well as geographic contours of what where we were flying (Salt Lake City). If you want to see it shoot me a PM with your email and I will send it along. (Or if someone knows how to post a word document or pull images off of it I will just post it here).

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