I have been trying to setup an Octo for some time running 3.3.3 with a Septentrio RTK GPS.
It has been flying fine with a UBlox M8N, then the Septentrio in NMEA mode.
There were 3 compasses, one in the Pixhawk, one in the Setentrio which is mounted beside the Pixhawk, and a stand alone HMC5983 mounted high on the Copter. I could never get all 3 calibrated through Mission Planner.
The radios to the GPS base station finally arrived and we started testing.
First step was to change the GPS type to SBF and setup GPS Injection from Mission Planner.
There seemed to be numerous issues including slow random updates in the GPS position, lots of compass errors and finally failed loiter flights due to immense toilet bowling.
Today I updated the firmware to 3.4-rc5 after removing all but the internal Pixhawk compass.
Did the compass cal which went fine although it kept auto completing very quickly so I manually tuned till I had about 3000 points and accepted that.
The GPS had a solid 3D Fix with 15 sats and after ground checks all seemed well enough to test fly.
Stabilise was good although it seemed a bit sensitive, especially to yaw inputs when correcting a slight yaw wandering.
I was keeping it between 1m and 2m off the ground and when in stable hover selected Loiter.
I received the warning beeps that it was refusing Loiter and it was staying in stabilise.
Switched back to Stab and checked the telemetry readout on the Graupner Tx and all looked OK.
Selected Loiter again and it refused again.
At this point hind sight tells me I should have landed and looked for the trouble but…
I thought 3rd time lucky!
Not so much.
It almost immediately rolled and pitched into the ground.
I am no whiz at log reading but I did notice the oscillations in Roll/Pitch/Yaw which to me is indicating overtuned.
As I have done many successful FW updates with the same settings I am assuming I rushed into 3.4 a bit quick without altering anything.
What I am curious about though is why the dive and flip is not indicated in the logs.
If some kind soul would look at these logs for me and give me a slap in the direction I have stuffed up I would be really grateful.
3DR Pixhawk w/Crius HV Power Module
BEC into output rail w/Zener over voltage protection
MavToHOTT telemetry module in Comm2
Septentrio RTK GPS
Graupner Tx and Rx
T-motor U5 motors w/T-Air 40A ESC’s
T_motor 15x5 Props
1000 size Octo frame
6S 22000 battery
2 22-09-2016 11-48-24 AM.zip (3.3 MB)
PS: Looking into the logs the altitude goes negative because I took off at a higher point then flew it in stabilise down the hill a bit to where I generally test Loiter (easier than carrying it )