I finally have a proper location where I can do some field testing. I'm using a recent (2 weeks) master branch with venus skytraq GPS and eagletree airspeed sensor.
A maiden flight has already been executed with a couple of surprises on handling, but all went ok.
The entire flight was on manual and I had a chance to test and see how photo's were made.
Today I attempted to make a stabilized flight to see how the aircraft handles that and to test some new camera settings to improve overall focus. I had to abort during final response verifications:
1. At one point in time, the control surfaces locked and there was no response whatsoever. Unfortunately I did not look at the PFD at this point. Switching to manual worked and control surfaces responded correctly and timely in that mode.
I repowered up and then stabilized mode was reasonable again.
2. Does the IMU initialize at the start? I had the aircraft leaning on one wing and the PFD showed a 10 degree roll to that side. I repowered up with the aircraft level and this disappeared. Basically, must the aircraft be completely level
at startup?
3. I eventually aborted the takeoff when I noticed that yawing the plane around in a plane parallel to the ground, the discrepancy in roll moved to the pitch, then back to roll (other side) and back to pitch. This sort of behavior *can* be produced
if the yawing plane is not parallel to the ground, but I paid very close attention to this process. I would expect the discrepancy in roll to move along during the yaw motion, but this did not happen.
4. I'm also getting the famous "Invalid argument "latlong_of_utm"" error when the GPS is 3D locked (actually, after 30 seconds or so).
The "utm_zone" should be 25, but it switches to 96 (which does not exist), even though I'm roughly at 8S, 35W. I think there's a serious error with units in that subsystem. Velocities and ground speeds seem to work ok, as well as vertical speeds.
Binary command set is here: http://www.sparkfun.com/datasheets/GPS/Modules/AN0003_v1.4.14_FlashOnly.pdf (NAVIGATION DATA MESSAGE).
I have "GPS_USE_LATLONG" defined and it does indeed come up in the make settings of the compiled binary.
5. The venus skytraq lat/lon is scaled to 1e7. Is the UBX lat/lon scaled the same way?
6. The alt also seems a bit off. I did a manual flight of around 12-20 meters altitude, but the altitude never reported anything higher
than a meter. I'm guessing it's off by a 100. What is the scale for UBX altitude?