diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp
index 77c419c33d..c7ea421b70 100644
--- a/src/modules/mavlink/mavlink_receiver.cpp
+++ b/src/modules/mavlink/mavlink_receiver.cpp
@@ -835,6 +835,9 @@ MavlinkReceiver::handle_message_att_pos_mocap(mavlink_message_t *msg)
 	mocap_odom.q[2] = mocap.q[2];
 	mocap_odom.q[3] = mocap.q[3];
 
+	size_t URT_SIZE = sizeof(mocap_odom.pose_covariance) / sizeof(mocap_odom.pose_covariance[0]);
+	assert(URT_SIZE == (sizeof(mocap.covariance) / sizeof(mocap.covariance[0])));
+
 	for (size_t i = 0; i < URT_SIZE; i++) {
 		mocap_odom.pose_covariance[i] = mocap.covariance[i];
 	}
@@ -1171,6 +1174,9 @@ MavlinkReceiver::handle_message_vision_position_estimate(mavlink_message_t *msg)
 	matrix::Quatf q(matrix::Eulerf(ev.roll, ev.pitch, ev.yaw));
 	q.copyTo(visual_odom.q);
 
+	size_t URT_SIZE = sizeof(visual_odom.pose_covariance) / sizeof(visual_odom.pose_covariance[0]);
+	assert(URT_SIZE == (sizeof(ev.covariance) / sizeof(ev.covariance[0])));
+
 	for (size_t i = 0; i < URT_SIZE; i++) {
 		visual_odom.pose_covariance[i] = ev.covariance[i];
 	}
@@ -1208,8 +1214,13 @@ MavlinkReceiver::handle_message_odometry(mavlink_message_t *msg)
 	matrix::Quatf q(odom.q);
 	q.copyTo(odometry.q);
 
+	size_t POS_URT_SIZE = sizeof(odometry.pose_covariance) / sizeof(odometry.pose_covariance[0]);
+	size_t VEL_URT_SIZE = sizeof(odometry.velocity_covariance) / sizeof(odometry.velocity_covariance[0]);
+	assert(POS_URT_SIZE == (sizeof(odom.covariance) / sizeof(odom.covariance[0])));
+	assert(VEL_URT_SIZE == (sizeof(odom.twist_covariance) / sizeof(odom.twist_covariance[0])));
+
 	// create a method to simplify covariance copy
-	for (size_t i = 0; i < URT_SIZE; i++) {
+	for (size_t i = 0; i < POS_URT_SIZE; i++) {
 		odometry.pose_covariance[i] = odom.pose_covariance[i];
 	}
 
@@ -1231,7 +1242,7 @@ MavlinkReceiver::handle_message_odometry(mavlink_message_t *msg)
 		odometry.yawspeed = odom.yawspeed;
 
 		//TODO: Apply rotation matrix to transform from body-fixed NED to earth-fixed NED frame
-		for (size_t i = 0; i < URT_SIZE; i++) {
+		for (size_t i = 0; i < VEL_URT_SIZE; i++) {
 			odometry.velocity_covariance[i] = odom.twist_covariance[i];
 		}
 
@@ -1253,7 +1264,7 @@ MavlinkReceiver::handle_message_odometry(mavlink_message_t *msg)
 			odometry.yawspeed = odom.yawspeed;
 
 			//TODO: Apply rotation matrix to transform from body-fixed to earth-fixed NED frame
-			for (size_t i = 0; i < URT_SIZE; i++) {
+			for (size_t i = 0; i < VEL_URT_SIZE; i++) {
 				odometry.velocity_covariance[i] = odom.twist_covariance[i];
 			}
 
@@ -1278,7 +1289,7 @@ MavlinkReceiver::handle_message_odometry(mavlink_message_t *msg)
 			odometry.yawspeed = angvel_local(2);
 
 			//TODO: Apply rotation matrix to transform from earth-fixed to body-fixed NED frame
-			for (size_t i = 0; i < URT_SIZE; i++) {
+			for (size_t i = 0; i < VEL_URT_SIZE; i++) {
 				odometry.velocity_covariance[i] = odom.twist_covariance[i];
 			}
 
diff --git a/src/modules/mavlink/mavlink_receiver.h b/src/modules/mavlink/mavlink_receiver.h
index 0fddef7dc6..54fb7a3c09 100644
--- a/src/modules/mavlink/mavlink_receiver.h
+++ b/src/modules/mavlink/mavlink_receiver.h
@@ -266,8 +266,6 @@ private:
 	param_t _p_bat_crit_thr;
 	param_t _p_bat_low_thr;
 
-	static const size_t URT_SIZE = 21;
-
 	MavlinkReceiver(const MavlinkReceiver &) = delete;
 	MavlinkReceiver operator=(const MavlinkReceiver &) = delete;
 };
diff --git a/src/modules/simulator/simulator_mavlink.cpp b/src/modules/simulator/simulator_mavlink.cpp
index 16f69e6a45..52c933dc64 100644
--- a/src/modules/simulator/simulator_mavlink.cpp
+++ b/src/modules/simulator/simulator_mavlink.cpp
@@ -1156,7 +1156,7 @@ int Simulator::publish_odometry_topic(mavlink_message_t *odom_mavlink)
 		q.copyTo(odom.q);
 
 		/* The pose covariance URT */
-		for (size_t i = 0; i < 21; i++) {
+		for (size_t i = 0; i < (sizeof(odom.pose_covariance) / sizeof(odom.pose_covariance[0])); i++) {
 			odom.pose_covariance[i] = odom_msg.pose_covariance[i];
 		}
 
@@ -1170,7 +1170,7 @@ int Simulator::publish_odometry_topic(mavlink_message_t *odom_mavlink)
 		odom.yawspeed = odom_msg.yawspeed;
 
 		/* The velocity covariance URT */
-		for (size_t i = 0; i < 21; i++) {
+		for (size_t i = 0; i < (sizeof(odom.velocity_covariance) / sizeof(odom.velocity_covariance[0])); i++) {
 			odom.velocity_covariance[i] = odom_msg.twist_covariance[i];
 		}
 
@@ -1187,7 +1187,7 @@ int Simulator::publish_odometry_topic(mavlink_message_t *odom_mavlink)
 		q.copyTo(odom.q);
 
 		/* The pose covariance URT */
-		for (size_t i = 0; i < 21; i++) {
+		for (size_t i = 0; i < (sizeof(odom.pose_covariance) / sizeof(odom.pose_covariance[0])); i++) {
 			odom.pose_covariance[i] = ev.covariance[i];
 		}