uint8 NAVIGATION_STATE_MANUAL = 0		# Manual mode
uint8 NAVIGATION_STATE_ALTCTL = 1		# Altitude control mode
uint8 NAVIGATION_STATE_POSCTL = 2		# Position control mode
uint8 NAVIGATION_STATE_AUTO_MISSION = 3		# Auto mission mode
uint8 NAVIGATION_STATE_AUTO_LOITER = 4		# Auto loiter mode
uint8 NAVIGATION_STATE_AUTO_RTL = 5		# Auto return to launch mode
uint8 NAVIGATION_STATE_AUTO_RCRECOVER = 6	# RC recover mode
uint8 NAVIGATION_STATE_AUTO_RTGS = 7		# Auto return to groundstation on data link loss
uint8 NAVIGATION_STATE_AUTO_LANDENGFAIL = 8 	# Auto land on engine failure
uint8 NAVIGATION_STATE_AUTO_LANDGPSFAIL = 9	# Auto land on gps failure (e.g. open loop loiter down)
uint8 NAVIGATION_STATE_ACRO = 10		# Acro mode
uint8 NAVIGATION_STATE_UNUSED = 11		# Free slot
uint8 NAVIGATION_STATE_DESCEND = 12		# Descend mode (no position control)
uint8 NAVIGATION_STATE_TERMINATION = 13		# Termination mode
uint8 NAVIGATION_STATE_OFFBOARD = 14
uint8 NAVIGATION_STATE_STAB = 15		# Stabilized mode
uint8 NAVIGATION_STATE_RATTITUDE = 16		# Rattitude (aka "flip") mode
uint8 NAVIGATION_STATE_AUTO_TAKEOFF = 17	# Takeoff
uint8 NAVIGATION_STATE_AUTO_LAND = 18		# Land
uint8 NAVIGATION_STATE_AUTO_FOLLOW_TARGET = 19	# Auto Follow
uint8 NAVIGATION_STATE_AUTO_PRECLAND = 20	# Precision land with landing target