commander: report GNSS yaw fault to user

src/modules/ekf2/EKF/common.h

@@ -487,6 +487,7 @@ union filter_control_status_u {
 		uint32_t ev_vel      : 1; ///< 24 - true when local frame velocity data fusion from external vision measurements is intended
 		uint32_t synthetic_mag_z : 1; ///< 25 - true when we are using a synthesized measurement for the magnetometer Z component
 		uint32_t vehicle_at_rest : 1; ///< 26 - true when the vehicle is at rest
+		uint32_t gps_yaw_fault : 1; ///< 27 - true when the GNSS heading has been declared faulty and is no longer being used
 	} flags;
 	uint32_t value;
 };

src/modules/ekf2/EKF/control.cpp

@@ -751,7 +751,7 @@ void Ekf::controlGpsFusion()
 void Ekf::controlGpsYawFusion(bool gps_checks_passing, bool gps_checks_failing)
 {
 	if (!(_params.fusion_mode & MASK_USE_GPSYAW)
-	    || _is_gps_yaw_faulty) {
+	    || _control_status.flags.gps_yaw_fault) {
 
 		stopGpsYawFusion();
 		return;
@@ -793,7 +793,7 @@ void Ekf::controlGpsYawFusion(bool gps_checks_passing, bool gps_checks_failing)
 					} else if (starting_conditions_passing) {
 						// Data seems good, but previous reset did not fix the issue
 						// something else must be wrong, declare the sensor faulty and stop the fusion
-						_is_gps_yaw_faulty = true;
+						_control_status.flags.gps_yaw_fault = true;
 						stopGpsYawFusion();
 
 					} else {

src/modules/ekf2/EKF/ekf.h

@@ -536,7 +536,6 @@ private:
 	// height sensor status
 	bool _baro_hgt_faulty{false};		///< true if valid baro data is unavailable for use
 	bool _gps_hgt_intermittent{false};	///< true if gps height into the buffer is intermittent
-	bool _is_gps_yaw_faulty{false};		///< true if gps yaw data is rejected by the filter for too long
 
 	// imu fault status
 	uint64_t _time_bad_vert_accel{0};	///< last time a bad vertical accel was detected (uSec)

src/modules/ekf2/EKF/ekf_helper.cpp

@@ -1698,7 +1698,7 @@ bool Ekf::resetYawToEKFGSF()
 			_warning_events.flags.emergency_yaw_reset_mag_stopped = true;
 
 		} else if (_control_status.flags.gps_yaw) {
-			_is_gps_yaw_faulty = true;
+			_control_status.flags.gps_yaw_fault = true;
 			_warning_events.flags.emergency_yaw_reset_gps_yaw_stopped = true;
 
 		} else if (_control_status.flags.ev_yaw) {