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GPX Log: Heading?

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Hi all,

I cannot find a parameter like "heading" in the gpx log. Therefore I assume that this info is included in the "compass" parameter, see http://wiki.mikrokopter.de/GPX:

<Compass>349,344,356,357</Compass> --> >Yaw Gyro stabilized Compass signal ; compass signal (raw) ; Compass setpoint (corrected with declination) ; Gyro Compass corrected (declination)

My question is: which one is the true heading value? The last one "Gyro Compass corrected (declination)"?

Regards, Armin
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ArminW meinte
I cannot find a parameter like "heading" in the gpx log. Therefore I assume that this info is included in the "compass" parameter, see http://wiki.mikrokopter.de/GPX:

My question is: which one is the true heading value?

I think heading is the field called course.

<Course>194</Course> --> GPS course over grund (independent from the compass of the MK
« Bearbeitet von Foersom am 24.04.2016 15:27. »
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@ArminW ; I think the Fourth value: Corrected Compass value (declination)

@Foersom; Does Course value use for heading or independent value for GPS?
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@ArminW ; I think the Fourth value: Corrected Compass value (declination)

@Foersom; Does Course value use for heading or independent value for GPS?

After reading some more about course / heading I can see that my previous answer was wrong. Heading is the direction the micro-copter is pointing, NOT the direction it is moving.
« Bearbeitet von Foersom am 25.04.2016 08:38. »
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thanks, Foersom and mehmetyldz87 for your suggestions.

I asked Lothar Freudenberg from MK and analysed some GPX log examples for myself. So I found the following conclusions, which I want to share with you...

(1) Heading = the direction, in which the kopter points. This may be the same direction the kopter moves. In this special case, heading = course. Generally, the heading and moving directions are not equal.

(2) The heading information is hidden in the parameter "compass". In older versions of the GPX logs, there are 2 compass values, in newer version these are 4. The wiki http://wiki.mikrokopter.de/GPX explains this unfortunately very rudimentary:

<Compass>349,344,356,357</Compass> --> >Yaw Gyro stabilized Compass signal ; compass signal (raw) ; Compass setpoint (corrected with declination) ; Gyro Compass corrected (declination)

An example with my interpretation:
example GPX log chart

compass[2] = original compass value
compass[1] = averaged compass[2]
compass[4] = compass[1] with applied correction of magnetic declination
compass[3] = compass[4] with again some averaging

I think, the best parameter for the heading is:

heading = compass[4].

(3) Some complications appear in the special case, when the FlightControl is mounted with some angle to the front direction. The GPX files saves the "FCOrientation" in the header part. In my example the FC is moved 45 degrees ccw (seen from top) and the GPX file says:

<FCOrientation>45</FCOrientation>

The compass values always refer to the compass direction, which equals the FC direction. Therefore:

heading = compass[4] + FCOrientation


Armin
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ArminW meinte
I asked Lothar Freudenberg from MK and analysed some GPX log examples for myself. So I found the following conclusions, which I want to share with you...

Thanks for the detailed explanation.
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The MKGpxTool for analyzing the GPX logs is updated (link). Now the correct heading with FCOrientations not equal zero is realized.

Thank you Franco.

Regards, Armin

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