Re: [Paparazzi-devel] Another day at the flying field...

[Gerard Toonstra]

3. The GPS course for the skytraq is still off. I'm again investigating this. The course at 90 deg. east seems to be 0 and when actually moving
    counterclockwise has the course increasing. Unfortunately I can't see what values come out of the ned_of_ecef_vect_i   calculation.
    I may have to debug this on my spare lisa and walk around the block here to see this in more detail.

I think I got to the bottom of it. It's confusion about which parameter in the NED structure is north. I assumed this would've been Y
and X would be east, but apparently x/y/z is just the order of parameters n/e/d.  Confirmed?

The current code used for testing was  (x assumed east, y assumed north ):

      gps.course = (atan2f( (float)gps.ned_vel.x, (float)gps.ned_vel.y )) * 1e7;

So just switching them around should do the trick. I tested this in python and for a couple of test vectors it produced correct results.

      gps.course = (atan2f( (float)gps.ned_vel.y, (float)gps.ned_vel.x )) * 1e7;


1. Is the course 0-360 deg (in rad *1e7), or is this [-180,180]?

2. The plane in the GCS also points in a very strange direction and not even close to the erroneous direction. 
    How is the rotation of the plane in the GCS determined?

G>