Ardupilot novice - navigation question


Please find attached a picture of a rover that I have fabricated for use on our farm.

It uses a pixhawk 2.1 cube with Here+ GPS which attach to motor controllers to manage 4 wheel drive skid steering. The ground speed is 0.3 metres per second. Power is from batteries which are charged by the generator. It’s built to be reasonably heavy duty to allow it to carry 200 litres of liquid chemical.

It was navigating reasonably well (I haven’t yet worked out how to use RTK), but recently it seems to have a “mind of its own”. It may be that I have accidentally changed a setting or something similar, but as a complete novice on all things remote control i’m struggling to determine where to start. I hope that I have correctly attached the data logs from a recent mission

Any assistance would be greatly appreciated.

Rover image

29 10-06-2021 4-21-50 PM.bin.log.param (16.1 KB)

That is the parameter file. You want to connect to your vehicle and go here:

I have been able to locate a number of .bin files - many seem to be generated at the same time, but of varying file sizes. I also followed Kenny Trussell’s advice and removed the micro SD card which (I think) has data from a trial on 27 May and on 10 June. I’m not sure what information is conveyed in the .bin file, but 1 mission may appear a little irregular after an emergency stop after a collision with a paddock fence.


Ok, so you have all the BIN files in there but you need to highlight exactly what the problem is. “mind of its own” is not a good description.

I would suggest showing a video of the problem, describing what you expect it to do, providing the log associated with that video.

Hi Leonard

Thanks for this. I have attached a BIN file and video of a recent test. The flight plan is hopefully visible on the Ardupilot screen. I was expecting it to follow the flighplan to waypoint 1 but the machine turned and drove in the opposite direction to expected. The test was terminated shortly after.

Any thoughts are most welcome.


It is going backwards when it should be going forwards…

You also drive it in reverse all the way back to the shed afterwards.

So is it backwards or are the motors reversed?

Hi Leonard

I appreciate your input. I did some rewiring and adjustment on the radio controller and I believe I have the machine running in a forwards direction. At the next test the rover made its way to 2 waypoints, but then stopped and “shuffled”. I have attached a video and .bin log. Any thoughts on what has occurred here are most welcome.

Best Regards

Your steering appears to be reversed. Looking at your rc input vs your yaw it looks like when your yaw command goes positive (should be right) it turns left.

I would make sure your stick input matches what you see in mission planner, you go right it goes right. Then make sure the vehicle turns right to. Stick -> Mission Planner -> Vehicle all matching.


I did some rewiring and adjusted some directions in the radio transmitter. At present, the stick input matches mission planner and the vehicle, that is;
Stick forward - Pitch and Throttle increase
Stick reverse - Pitch and Throttle decrease
Stick hard right (skid right) - Pitch increase, Throttle decrease as the left wheels drive forward and the right wheels drive backwards
Stick hard left (skid left) - Pitch decrease, Throttle increase to initiate a skid to the left.

The vehicles drives well in manual mode, but when in auto mode, the vehicle is facing the correct direction with the “current heading”, “direction to current WP” and “target heading” all appearing normal, but the GPS track line causes the vehicle to drive in the opposite direction. I have attached the .bin file and a screen shot of the problem.

Any input welcome