I’d like some help with analysing a BIN file and suggestions to help get better flight data. I’m writing a system that uses ArduPlane as a low-cost flight LOGGER in real-sized aerobatic aircraft. My software was originally based on FlightCoach.
For the past year, I have been flying a low powered Slingsby Firefly and getting good results from a cheap Omnibus F4 and a Beitian BN-880 GPS. I’ve since stepped up to an Extra 300, high performance aircraft doing more radical manouvres - flick rolls and a lot more time spent inverted. Consequently, I’m losing the GPS signal more often. The Ardupilot EKF is now becoming very unstable.
I’ve recently upgraded my hardware to Pixhawk Mini 6C controller with a larger Beitian M10 GPS(BE-450). This has dual IMUs and a faster processor which has helped matters. I now get the occasional “reset” when the GPS is re-acquired and only a few minutes of crazy EKF instability on a flight. The EKF eventually resets and the remainder of the flight data is acceptable.
Here’s my BIN file:
The take off occurs at 11:55:08 and the PM/Load data jumps from 60% to 85%. Is this acceptable? Should I only be using one IMU? Should I slow down the logging from LOG_FILE_RATEMAX = 30 hz?
There’s a “Reset Glitch” at 11:58:28. The number of satellites drops to zero, but seconds later it’s back to 20. Can the EKF instability be “smoothed” out?
The major instability is between 12:14:01 and 12:16:26. Once again the satellites drop to zero. Interestingly the PM/load drops from 85% to 58% and then stabilises at 62% for the rest of the flight. Why does the load drop? The EKF goes crazy as shown by XFK3/IPE.
I realise that I could put a second GPS sensor on the bottom of the aircraft, but fitting a permanently wired GPS sensor would involve CAA approvals - a nightmare. I’m hoping that there is some way of stopping the EKF becoming so unstable when it loses the GPS…
Any help would be greatly appreciated.
1 post - 1 participant
Read full topic
