IMU data unstable


#1

Hi,

We are trying to echo flytos/mavros/local_position/local after GPS lock to extract IMU data. The imu data seems to be very unstable. We left FCU untouched, but the IMU data has fluctuations of at least ± 50cm. Is there anything we can do to make it more stable?
Thanks!


#2

Hello,

Are you using PX4? Is it the latest version v1.8?
Moreover, what was the number of satellites locked via GPS? Also, it’s HDOP/VDOP.


#3

Hi there Sharvashish, thank you for the reply. Kelly and I are working together in the same team so I’ll add on if I may. We are using PX4 firmware version 1.7.3.

In QGC, no matter how often we calibrate the sensors (compass, gyro, accelerometer and horzontal level), there is always an inconsistent mag sensors error. I have attached screenshot of this error and our version here.

We intend to do autonomous flying in ROS, so I’ve attached videos about our observations in ROS.

We are echoing /tf in the video. We publish to the ROS topic /tf using data from IMU based on the original ROS topic /flytos/mavros/local_position/local.

We have two reference frames, one world frame, and one base_link frame which represents the reference frame of the drone.


We have GPS lock, and the PX4 is RC armed. It can see 14 satellites connected on FlytOS and QGC.

I have also echoed all the other ROS topics pertaining to /flytos/mavros/ assuming that all these topics have something to do with the GPS signal, but it seems I get nothing spitting out into these topics.

Finally, the fluctuations are about 50cm / s ^ to add onto Kelly’s points. It flies around wildly on the map, and we tried translating the pixhawk by 10 metres physically in one direction but it doesn’t seem to have any effect on the actual /tf values - it still continues to fly around wildly and randomly.

Thank you very much for the support, hope to hear from you soon :slight_smile:

Cheers
Sam


#4

Sorry, in the last video, ignore the point cloud that is being generated. The resolution is not very clear but the drone that is moving is the one at the end of the yellow tether line.

The PX4 was stationary all the time, so it should not even be moving…


#5

Hi @SamLow and @kellykhoooo,

It would take me some time to get through the above videos. But since all of it has everything to do with PX4, I would suggest you guys post your issue on their forum as well.