diff --git a/msg/vehicle_attitude.msg b/msg/vehicle_attitude.msg
index 2c64c32e13..a7d02ac963 100644
--- a/msg/vehicle_attitude.msg
+++ b/msg/vehicle_attitude.msg
@@ -18,3 +18,5 @@ float32[4] q		# Quaternion (NED)
 float32[3] g_comp	# Compensated gravity vector
 bool R_valid		# Rotation matrix valid
 bool q_valid		# Quaternion valid
+
+# TOPICS vehicle_attitude vehicle_attitude_groundtruth
diff --git a/src/modules/logger/logger.cpp b/src/modules/logger/logger.cpp
index 6f6b5fdb3d..4c7038c5bc 100644
--- a/src/modules/logger/logger.cpp
+++ b/src/modules/logger/logger.cpp
@@ -476,6 +476,7 @@ bool Logger::copy_if_updated_multi(LoggerSubscription &sub, int multi_instance,
 void Logger::add_default_topics()
 {
 	add_topic("vehicle_attitude", 10);
+	add_topic("vehicle_attitude_groundtruth", 10);
 	add_topic("actuator_outputs", 50);
 	add_topic("telemetry_status", 50);
 	add_topic("vehicle_command");
diff --git a/src/modules/simulator/simulator.h b/src/modules/simulator/simulator.h
index f23efc217d..812686a3a4 100644
--- a/src/modules/simulator/simulator.h
+++ b/src/modules/simulator/simulator.h
@@ -245,6 +245,7 @@ private:
 #ifndef __PX4_QURT
 		,
 		_rc_channels_pub(nullptr),
+		_attitude_pub(nullptr),
 		_actuator_outputs_sub{},
 		_vehicle_attitude_sub(-1),
 		_manual_sub(-1),
@@ -306,6 +307,7 @@ private:
 #ifndef __PX4_QURT
 	// uORB publisher handlers
 	orb_advert_t _rc_channels_pub;
+	orb_advert_t _attitude_pub;
 
 	// uORB subscription handlers
 	int _actuator_outputs_sub[ORB_MULTI_MAX_INSTANCES];
diff --git a/src/modules/simulator/simulator_mavlink.cpp b/src/modules/simulator/simulator_mavlink.cpp
index 003f3fe9c2..6911cb4285 100644
--- a/src/modules/simulator/simulator_mavlink.cpp
+++ b/src/modules/simulator/simulator_mavlink.cpp
@@ -41,6 +41,8 @@
 #include <netinet/in.h>
 #include <pthread.h>
 
+#include <mathlib/mathlib.h>
+
 extern "C" __EXPORT hrt_abstime hrt_reset(void);
 
 #define SEND_INTERVAL 	20
@@ -301,7 +303,40 @@ void Simulator::handle_message(mavlink_message_t *msg, bool publish)
 		}
 
 		break;
+
+	case MAVLINK_MSG_ID_HIL_STATE_QUATERNION:
+		mavlink_hil_state_quaternion_t hil_state;
+		mavlink_msg_hil_state_quaternion_decode(msg, &hil_state);
+
+		uint64_t timestamp = hrt_absolute_time();
+
+		/* attitude */
+		struct vehicle_attitude_s hil_attitude;
+		{
+			hil_attitude.timestamp = timestamp;
+
+			math::Quaternion q(hil_state.attitude_quaternion);
+			math::Matrix<3, 3> C_nb = q.to_dcm();
+			math::Vector<3> euler = C_nb.to_euler();
+
+			hil_attitude.q[0] = q(0);
+			hil_attitude.q[1] = q(1);
+			hil_attitude.q[2] = q(2);
+			hil_attitude.q[3] = q(3);
+			hil_attitude.q_valid = true;
+
+			hil_attitude.roll = euler(1);
+			hil_attitude.pitch = euler(0);
+			hil_attitude.yaw = euler(2);
+
+			if (true) {
+				int hilstate_multi;
+				orb_publish_auto(ORB_ID(vehicle_attitude_groundtruth), &_attitude_pub, &hil_attitude, &hilstate_multi, ORB_PRIO_HIGH);
+			}
+		}
+		break;
 	}
+
 }
 
 void Simulator::send_mavlink_message(const uint8_t msgid, const void *msg, uint8_t component_ID)
diff --git a/src/systemcmds/mixer/mixer.cpp b/src/systemcmds/mixer/mixer.cpp
index 773faffc11..996a220b91 100644
--- a/src/systemcmds/mixer/mixer.cpp
+++ b/src/systemcmds/mixer/mixer.cpp
@@ -91,7 +91,7 @@ mixer_main(int argc, char *argv[])
 		int ret = load(argv[2], argv[3], true);
 
 		if (ret != 0) {
-			warnx("failed to append mixer");
+			PX4_ERR("failed to append mixer");
 			return 1;
 		}