ROStopics: accessing estimates from estimator


I have a question regarding the different topics that are advertised by Rosflight_io.

Is the /imu/data topic the unfiltered/raw measurements from the onboard IMU?

Also, is the rostopic attitude/ filtered attitude angles and angular velocities? When I am running a simulation in Gazebo, /attitude doesn’t seem to update when I rotate the quadcopter around the z-axis using the rotation tool in Gazebo. Is this due to the estimator being unable to detect the sudden rotation?

Hey Bernhard! Good to see you here.

Yes, the /imu/data topic is essentially raw (there is actually some light “filtering”—really just sample rate conversion—happening so that as much info as possible can be squeezed out when using a lower rate. see also here).

The /attitude topic contains estimated attitude using the gyro+accelerometer in a non-linear complementary filter fashion. It also contains low-pass filtered angular velocities (gains set here) with estimated dynamic bias removed.

Correct, when “teleporting” in gazebo, no forces and moments are actually applied to the vehicle, so there is no way for the IMU to have sensed anything. Try using an RC transmitter or your keyboard to fly the vehicle in sim and you will see signal behaviors as expected.

I see, that explains it! Thanks for helping out.