Unable to setup Compass Sensor for simulation

[Adam.Davidson]

I’m attempting to use an x500 with Gazebo simulator. However, I get this error when running the simulation:

INFO:gazebo.stream_logger.x500_0.px4:stdout: WARN [health_and_arming_checks] Preflight Fail: Compass Sensor 0 missing

I have added a magnetometer to the x500 model.sdf following SDF 1.9 (SDFormat Specification):

      <sensor name="magnetometer_sensor" type="magnetometer">
        <magnetometer>
          <x>
            <noise type="gaussian">
              <mean>0</mean>
              <stddev>0.00018665</stddev>
              <dynamic_bias_stddev>3.8785e-05</dynamic_bias_stddev>
              <dynamic_bias_correlation_time>1000</dynamic_bias_correlation_time>
            </noise>
          </x>
          <y>
            <noise type="gaussian">
              <mean>0</mean>
              <stddev>0.00018665</stddev>
              <dynamic_bias_stddev>3.8785e-05</dynamic_bias_stddev>
              <dynamic_bias_correlation_time>1000</dynamic_bias_correlation_time>
            </noise>
          </y>
          <z>
            <noise type="gaussian">
              <mean>0</mean>
              <stddev>0.00018665</stddev>
              <dynamic_bias_stddev>3.8785e-05</dynamic_bias_stddev>
              <dynamic_bias_correlation_time>1000</dynamic_bias_correlation_time>
            </noise>
          </z>
        </magnetometer>
      </sensor>

I have followed the same process as the IMU which seems to be working fine.
Any help would be much appreciated.

[xdwgood]

I think you don’t need to add it. The gz simulation should still work. Because currently, mag sensor data is generated using GPS data during gz simulation.(see px4 code：PX4-Autopilot/src/modules/simulation/sensor_mag_sim/SensorMagSim.cpp at 6b0ac49daf5c49aeb625ed684359fdd59b1a287d · PX4/PX4-Autopilot · GitHub)

Even if you want to add a separate geomagnetic sensor, in addition to the changes you made above. We also need to add

Mag sensor: /world/$WORLD/model/$MODEL/link/base_link/sensor/
magnetometer_sensor/magnetometer
std::string air_pressure_topic = “/world/” + _world_name + “/model/” + _model_name + “/link/base_link/sensor/magnetometer_sensor/magnetometer”;

if (!_node.Subscribe(magnetometer_topic, &GZBridge::magnetometerCallback, this)) {
return PX4_ERROR;
}

to GZBridge.cpp.

There is a similar situation here: [Bug] Sometimes topic sensor_gps not updated in gz simulation · Issue #23130 · PX4/PX4-Autopilot · GitHub

[xdwgood]

I wrote some code to implement the use of the magnetometer module in Gazebo and tested it for takeoff, and it seems to be working normaly.

[Adam.Davidson]

Thanks for your help. The solution for me was to remove the magnetometer sensor altogether, and add the navsat plugin to the model file e.g.
<plugin name='gz::sim::systems::NavSat' filename='gz-sim-navsat-system'/>