diff --git a/msg/position_controller_status.msg b/msg/position_controller_status.msg
index 1ae30ffaff..2f2531bfbf 100644
--- a/msg/position_controller_status.msg
+++ b/msg/position_controller_status.msg
@@ -2,10 +2,10 @@ uint64 timestamp		# time since system start (microseconds)
 
 float32 nav_roll
 float32 nav_pitch
-float32 nav_bearing
+float32 nav_bearing 	# set to NAN if not valid
 
-float32 target_bearing
-float32 xtrack_error
+float32 target_bearing	# set to NAN if not valid
+float32 xtrack_error	# set to NAN if not valid
 
 float32 wp_dist