compute secondary attitude with reference frame rotated -90 degress around pitch axis of original reference frame (used for VTOL)

src/modules/attitude_estimator_ekf/attitude_estimator_ekf_main.cpp

@@ -552,6 +552,44 @@ const unsigned int loop_interval_alarm = 6500;	// loop interval in microseconds
 					memcpy(&att.R[0][0], &R.data[0][0], sizeof(att.R));
 					att.R_valid = true;
 
+					// compute secondary attitude
+					math::Matrix<3, 3> R_adapted;		//modified rotation matrix
+					R_adapted = R;
+
+					//move z to x
+					R_adapted(0, 0) = R(0, 2);
+					R_adapted(1, 0) = R(1, 2);
+					R_adapted(2, 0) = R(2, 2);
+					//move x to z
+					R_adapted(0, 2) = R(0, 0);
+					R_adapted(1, 2) = R(1, 0);
+					R_adapted(2, 2) = R(2, 0);
+
+					//change direction of pitch (convert to right handed system)
+					R_adapted(0, 0) = -R_adapted(0, 0);
+					R_adapted(1, 0) = -R_adapted(1, 0);
+					R_adapted(2, 0) = -R_adapted(2, 0);
+					math::Vector<3> euler_angles_sec;		//adapted euler angles for fixed wing operation
+					euler_angles_sec = R_adapted.to_euler();
+
+					att.roll_sec    = euler_angles_sec(0);
+					att.pitch_sec   = euler_angles_sec(1);
+					att.yaw_sec     = euler_angles_sec(2);
+
+					memcpy(&att.R_sec[0][0], &R_adapted.data[0][0], sizeof(att.R_sec));
+
+					att.rollspeed_sec  = -x_aposteriori[2];
+					att.pitchspeed_sec = x_aposteriori[1];
+					att.yawspeed_sec   = x_aposteriori[0];
+					att.rollacc_sec    = -x_aposteriori[5];
+					att.pitchacc_sec   = x_aposteriori[4];
+					att.yawacc_sec     = x_aposteriori[3];
+
+					att.g_comp_sec[0] = -raw.accelerometer_m_s2[2] - (-acc(2));
+					att.g_comp_sec[1] = raw.accelerometer_m_s2[1] - acc(1);
+					att.g_comp_sec[2] = raw.accelerometer_m_s2[0] - acc(0);
+
+
 					if (isfinite(att.roll) && isfinite(att.pitch) && isfinite(att.yaw)) {
 						// Broadcast
 						orb_publish(ORB_ID(vehicle_attitude), pub_att, &att);