Gazebo simulation: Used Gazebo GPS plugin

[ahcorde]

Added Gps sensor that allows to setup the GPS in Gazebo

I'm getting these errors. Any thoughts?

WARN  [health_and_arming_checks] Preflight Fail: Strong magnetic interference
WARN  [health_and_arming_checks] Preflight Fail: Yaw estimate error

FYI @Jaeyoung-Lim @bperseghetti @dagar

[Jaeyoung-Lim]

@ahcorde Thanks for already looking into these!

Are the mag issues present when just adding the GPS sensor? If this is the case, wondering if it is related to the WMM magnetic model or something related to the geolocation and mag consistency

PX4-Autopilot/src/modules/ekf2/ekf2_params.c

Lines 1468 to 1480 in a1efafc

	/**
	* Magnetic field strength test selection
	*
	* When set, the EKF checks the strength of the magnetic field
	* to decide whether the magnetometer data is valid.
	* If GPS data is received, the magnetic field is compared to a World
	* Magnetic Model (WMM), otherwise an average value is used.
	* This check is useful to reject occasional hard iron disturbance.
	*
	* @group EKF2
	* @boolean
	*/
	PARAM_DEFINE_INT32(EKF2_MAG_CHECK, 1);

[ahcorde]

@ahcorde Thanks for already looking into these!

Are the mag issues present when just adding the GPS sensor? If this is the case, wondering if it is related to the WMM magnetic model or something related to the geolocation and mag consistency

PX4-Autopilot/src/modules/ekf2/ekf2_params.c

Lines 1468 to 1480 in a1efafc

	/**
	* Magnetic field strength test selection
	*
	* When set, the EKF checks the strength of the magnetic field
	* to decide whether the magnetometer data is valid.
	* If GPS data is received, the magnetic field is compared to a World
	* Magnetic Model (WMM), otherwise an average value is used.
	* This check is useful to reject occasional hard iron disturbance.
	*
	* @group EKF2
	* @boolean
	*/
	PARAM_DEFINE_INT32(EKF2_MAG_CHECK, 1);

I was trying to include both at the same time (gps and magnetometer) but it's not clear for me how to match the values:

The magnetometer from Gazebo has magnetic field strength (in Tesla) along body-frame axis. I checked the PX4Magnetometer class but I couldn't find documentation.

[Jaeyoung-Lim]

I was trying to include both at the same time (gps and magnetometer) but it's not clear for me how to match the values:

Does this mean that in gazebo, when there is a spherical coordinate defined as geo coordinates, the magnetic field is not consistent with the geolocation of the world? If this is the case, would it be something desired to add this feature?

This was how it was being done for gazebo classic: https://github.com/PX4/PX4-SITL_gazebo-classic/blob/ec8641d48753b20d431842f88e95557f22ec318a/src/gazebo_magnetometer_plugin.cpp#L184-L197

[ahcorde]

I was trying to include both at the same time (gps and magnetometer) but it's not clear for me how to match the values:

Does this mean that in gazebo, when there is a spherical coordinate defined as geo coordinates, the magnetic field is not consistent with the geolocation of the world? If this is the case, would it be something desired to add this feature?

This was how it was being done for gazebo classic: https://github.com/PX4/PX4-SITL_gazebo-classic/blob/ec8641d48753b20d431842f88e95557f22ec318a/src/gazebo_magnetometer_plugin.cpp#L184-L197

Yep, this feature was not implemented in Gazebo, but here it is gazebosim/gz-sim#1907.

I still have some issue with the NED -> ENU conversion. The velocity published in the navsat msg is in ENU, but the internal px4 message is in NED coordinates. may this affect the magnetometer too ?

[Jaeyoung-Lim]

I still have some issue with the NED -> ENU conversion. The velocity published in the navsat msg is in ENU, but the internal px4 message is in NED coordinates. may this affect the magnetometer too ?

I would doubt that this makes a difference unless it happens during motion. Could you try disabling EKF2_MAG_CHECK and see if it fixes the mag warning? I would say then it is good enough to be in and we can wait until the gazebo changes are available

[ahcorde]

EKF2_MAG_CHECK

I added this param but I still have the issue

[Jaeyoung-Lim]

EKF2_MAG_CHECK
I added this param but I still have the issue

@bresch @dagar Any ideas how to fix this?

[bresch]

I tried in sim to fake a large mag field and I can arm without issues in alt mode if EKF2_MAG_CHECK is set to 0 or if COM_ARM_MAG_STR is set to 0.