VehicleLocalPosition (UORB message)

Fused local position in NED. The coordinate system origin is the vehicle position at the time when the EKF2-module was started.

TOPICS: vehicle_local_position vehicle_local_position_groundtruth external_ins_local_position estimator_local_position

Fields

Name	Type	Unit [Frame]	Range/Enum	Description
timestamp	uint64			time since system start (microseconds)
timestamp_sample	uint64			the timestamp of the raw data (microseconds)
xy_valid	bool			true if x and y are valid
z_valid	bool			true if z is valid
v_xy_valid	bool			true if vx and vy are valid
v_z_valid	bool			true if vz is valid
x	float32			North position in NED earth-fixed frame, (metres)
y	float32			East position in NED earth-fixed frame, (metres)
z	float32			Down position (negative altitude) in NED earth-fixed frame, (metres)
delta_xy	float32[2]			Amount of lateral shift of position estimate in latest reset (in x and y) [m]
xy_reset_counter	uint8			Index of latest lateral position estimate reset
delta_z	float32			Amount of vertical shift of position estimate in latest reset [m]
z_reset_counter	uint8			Index of latest vertical position estimate reset
vx	float32			North velocity in NED earth-fixed frame, (metres/sec)
vy	float32			East velocity in NED earth-fixed frame, (metres/sec)
vz	float32			Down velocity in NED earth-fixed frame, (metres/sec)
z_deriv	float32			Down position time derivative in NED earth-fixed frame, (metres/sec)
delta_vxy	float32[2]			Amount of lateral shift of velocity estimate in latest reset (in x and y) [m/s]
vxy_reset_counter	uint8			Index of latest vertical velocity estimate reset
delta_vz	float32			Amount of vertical shift of velocity estimate in latest reset [m/s]
vz_reset_counter	uint8			Index of latest vertical velocity estimate reset
ax	float32			North velocity derivative in NED earth-fixed frame, (metres/sec^2)
ay	float32			East velocity derivative in NED earth-fixed frame, (metres/sec^2)
az	float32			Down velocity derivative in NED earth-fixed frame, (metres/sec^2)
heading	float32			Euler yaw angle transforming the tangent plane relative to NED earth-fixed frame, -PI..+PI, (radians)
heading_var	float32
unaided_heading	float32			Same as heading but generated by integrating corrected gyro data only
delta_heading	float32			Heading delta caused by latest heading reset [rad]
heading_reset_counter	uint8			Index of latest heading reset
heading_good_for_control	bool
tilt_var	float32
xy_global	bool			true if position (x, y) has a valid global reference (ref_lat, ref_lon)
z_global	bool			true if z has a valid global reference (ref_alt)
ref_timestamp	uint64			Time when reference position was set since system start, (microseconds)
ref_lat	float64			Reference point latitude, (degrees)
ref_lon	float64			Reference point longitude, (degrees)
ref_alt	float32			Reference altitude AMSL, (metres)
dist_bottom_valid	bool			true if distance to bottom surface is valid
dist_bottom	float32			Distance from from bottom surface to ground, (metres)
dist_bottom_var	float32			height above ground estimate variance (m^2)
delta_dist_bottom	float32			Amount of vertical shift of dist bottom estimate in latest reset [m]
dist_bottom_reset_counter	uint8			Index of latest dist bottom estimate reset
dist_bottom_sensor_bitfield	uint8			bitfield indicating what type of sensor is used to estimate dist_bottom
eph	float32			Standard deviation of horizontal position error, (metres)
epv	float32			Standard deviation of vertical position error, (metres)
evh	float32			Standard deviation of horizontal velocity error, (metres/sec)
evv	float32			Standard deviation of vertical velocity error, (metres/sec)
dead_reckoning	bool			True if this position is estimated through dead-reckoning
vxy_max	float32			maximum horizontal speed (meters/sec)
vz_max	float32			maximum vertical speed (meters/sec)
hagl_min	float32			minimum height above ground level (meters)
hagl_max_z	float32			maximum height above ground level for z-control (meters)
hagl_max_xy	float32			maximum height above ground level for xy-control (meters)

Constants

Name	Type	Value	Description
MESSAGE_VERSION	uint32	1
DIST_BOTTOM_SENSOR_NONE	uint8	0
DIST_BOTTOM_SENSOR_RANGE	uint8	1	(1 << 0) a range sensor is used to estimate dist_bottom field
DIST_BOTTOM_SENSOR_FLOW	uint8	2	(1 << 1) a flow sensor is used to estimate dist_bottom field (mostly fixed-wing use case)

Source Message

Source file (GitHub)

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# Fused local position in NED.
# The coordinate system origin is the vehicle position at the time when the EKF2-module was started.

uint32 MESSAGE_VERSION = 1

uint64 timestamp			# time since system start (microseconds)
uint64 timestamp_sample                 # the timestamp of the raw data (microseconds)

bool xy_valid				# true if x and y are valid
bool z_valid				# true if z is valid
bool v_xy_valid				# true if vx and vy are valid
bool v_z_valid				# true if vz is valid

# Position in local NED frame
float32 x				# North position in NED earth-fixed frame, (metres)
float32 y				# East position in NED earth-fixed frame, (metres)
float32 z				# Down position (negative altitude) in NED earth-fixed frame, (metres)

# Position reset delta
float32[2] delta_xy			# Amount of lateral shift of position estimate in latest reset (in x and y) [m]
uint8 xy_reset_counter			# Index of latest lateral position estimate reset
float32 delta_z				# Amount of vertical shift of position estimate in latest reset [m]
uint8 z_reset_counter			# Index of latest vertical position estimate reset

# Velocity in NED frame
float32 vx 				# North velocity in NED earth-fixed frame, (metres/sec)
float32 vy				# East velocity in NED earth-fixed frame, (metres/sec)
float32 vz				# Down velocity in NED earth-fixed frame, (metres/sec)
float32 z_deriv				# Down position time derivative in NED earth-fixed frame, (metres/sec)

# Velocity reset delta
float32[2] delta_vxy			# Amount of lateral shift of velocity estimate in latest reset (in x and y) [m/s]
uint8 vxy_reset_counter			# Index of latest vertical velocity estimate reset
float32 delta_vz			# Amount of vertical shift of velocity estimate in latest reset [m/s]
uint8 vz_reset_counter			# Index of latest vertical velocity estimate reset

# Acceleration in NED frame
float32 ax        # North velocity derivative in NED earth-fixed frame, (metres/sec^2)
float32 ay        # East velocity derivative in NED earth-fixed frame, (metres/sec^2)
float32 az        # Down velocity derivative in NED earth-fixed frame, (metres/sec^2)

float32 heading				# Euler yaw angle transforming the tangent plane relative to NED earth-fixed frame, -PI..+PI,  (radians)
float32 heading_var
float32 unaided_heading                 # Same as heading but generated by integrating corrected gyro data only
float32 delta_heading			# Heading delta caused by latest heading reset [rad]
uint8 heading_reset_counter		# Index of latest heading reset
bool heading_good_for_control

float32 tilt_var

# Position of reference point (local NED frame origin) in global (GPS / WGS84) frame
bool xy_global				# true if position (x, y) has a valid global reference (ref_lat, ref_lon)
bool z_global				# true if z has a valid global reference (ref_alt)
uint64 ref_timestamp			# Time when reference position was set since system start, (microseconds)
float64 ref_lat				# Reference point latitude, (degrees)
float64 ref_lon				# Reference point longitude, (degrees)
float32 ref_alt				# Reference altitude AMSL, (metres)

# Distance to surface
bool dist_bottom_valid			# true if distance to bottom surface is valid
float32 dist_bottom			# Distance from from bottom surface to ground, (metres)
float32 dist_bottom_var                 # height above ground estimate variance (m^2)

float32 delta_dist_bottom               # Amount of vertical shift of dist bottom estimate in latest reset [m]
uint8 dist_bottom_reset_counter         # Index of latest dist bottom estimate reset

uint8 dist_bottom_sensor_bitfield	# bitfield indicating what type of sensor is used to estimate dist_bottom
uint8 DIST_BOTTOM_SENSOR_NONE = 0
uint8 DIST_BOTTOM_SENSOR_RANGE = 1	# (1 << 0) a range sensor is used to estimate dist_bottom field
uint8 DIST_BOTTOM_SENSOR_FLOW = 2	# (1 << 1) a flow sensor is used to estimate dist_bottom field (mostly fixed-wing use case)

float32 eph				# Standard deviation of horizontal position error, (metres)
float32 epv				# Standard deviation of vertical position error, (metres)
float32 evh				# Standard deviation of horizontal velocity error, (metres/sec)
float32 evv				# Standard deviation of vertical velocity error, (metres/sec)

bool dead_reckoning                     # True if this position is estimated through dead-reckoning

# estimator specified vehicle limits
# set to INFINITY when limiting not required
float32 vxy_max				# maximum horizontal speed (meters/sec)
float32 vz_max				# maximum vertical speed (meters/sec)
float32 hagl_min			# minimum height above ground level (meters)
float32 hagl_max_z			# maximum height above ground level for z-control (meters)
float32 hagl_max_xy			# maximum height above ground level for xy-control (meters)

# TOPICS vehicle_local_position vehicle_local_position_groundtruth external_ins_local_position
# TOPICS estimator_local_position