2.5 Key Sensor Specifications

Key Sensor Configuration

Sensor	Qty	Connection	Notes
3D LiDAR	1	Ethernet	360° 3D point cloud
2D LiDAR	2	USB	Front + Rear obstacle detection
RGB-D Camera	1	USB	Color + Depth
Mono Camera	4	V4L2	Front 3 + Rear 1
IMU	1	USB	6-axis (accel + gyro)
GNSS	1	USB	GPS receiver

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Sensor Coordinates

Positions and orientations of AntBot’s key sensors relative to base_link.
The tables show URDF defaults; see Sensor Calibration for per-robot measurements.

• Position: mm
• Angle: degree

Camera

Sensor	Position	X	Y	Z	Roll	Pitch	Yaw
Mono Camera	LEFT	260.000	254.770	587.500	0	0	90
Mono Camera	CENTER	358.070	0	587.500	0	0	0
Mono Camera	RIGHT	260.000	-254.770	587.500	0	0	-90
Mono Camera	BACK	-376.690	0	299.000	0	0	180
RGB-D Camera	CENTER	348.162	47.500	526.484	0	30	0

LiDAR

Sensor	Position	X	Y	Z	Roll	Pitch	Yaw
2D LiDAR	FRONT	325.000	0	255.000	0	180	0
2D LiDAR	BACK	-325.000	0	255.000	180	0	0
3D LiDAR	FRONT	225.332	0	724.904	0	10	0

Other Sensors

Sensor	X	Y	Z	Roll	Pitch	Yaw
IMU	240.000	6.75	390.200	0	0	180
GNSS	202.600	-128.000	660.000	0	0	180

Note

To check these coordinates in the URDF, refer to antbot_description/urdf/antbot.xacro.
For ROS topics published by each sensor, see Key ROS Topics/Services.

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Sensor Calibration

How Calibration Is Applied

Sensor extrinsic calibration data is measured for each robot during production.
If the file or a sensor entry is absent, the affected sensors use URDF defaults.

• File: ~/ANTBOT/calibration.yaml
• Reference: Sensor position and orientation relative to base_link
• Application: antbot_bringup replaces the URDF default coordinates with calibration values for sensor TFs

Field	Meaning	Unit
tx, ty, tz	X, Y, Z position	Meters (m)
rx, ry, rz	Roll, Pitch, Yaw	Radians (rad)

Example File

Key	Sensor	TF Frame
camera_front_extrinsic	Front mono camera	camera_mono_front_link
camera_left_extrinsic	Left mono camera	camera_mono_left_link
camera_right_extrinsic	Right mono camera	camera_mono_right_link
lidar_2d_back_extrinsic	Rear 2D LiDAR	lidar_2d_back_link
lidar_2d_front_extrinsic	Front 2D LiDAR	lidar_2d_front_link

camera_front_extrinsic:
  rx: 0.0004841534918956223
  ry: -0.022696397032526777
  rz: -0.024963586218731022
  tx: 0.3713665035809988
  ty: -0.0012114368184327506
  tz: 0.5819776834826769
camera_left_extrinsic:
  rx: -8.26610835375321e-05
  ry: 0.010437505309254372
  rz: 1.5477847272499485
  tx: 0.264771522661827
  ty: 0.2624195508373959
  tz: 0.5786230512170198
camera_right_extrinsic:
  rx: 0.005940643853633356
  ry: 0.017139707082721167
  rz: -1.5984502045959927
  tx: 0.26360728011109097
  ty: -0.2633683883510877
  tz: 0.5732517098202605

lidar_2d_back_extrinsic:
  rx: 3.141592653589793
  ry: 0.0
  rz: -0.018807469931779952
  tx: -0.325
  ty: 0.0
  tz: 0.255
lidar_2d_front_extrinsic:
  rx: 0.0
  ry: 3.141592653589793
  rz: -0.15944110598522698
  tx: 0.325
  ty: 0.0
  tz: 0.255