Data Format

The data was recorded under the Robot Operating System ( ROS), and the timestamp used in the data was in Ubuntu system time. Therefore, the format of the dataset is the standard ROS bag file. In other words, the sensor messages follow the standard ROS messages.

GNSS​

• Driver: The data from the GNSS receiver is collected based on the ROS driver.

• Data format:

  • Timestamp - unit second - ROS timestamp 

  • GNSS PRN - unit - Satellite index

  • Pseudorange - unit meter - the ance between satellite and receiver  

  • Carrier phase, Doppler

  • Carrier-to-noise ratio]

  • More message types can be found here.

IMU

• Driver: The data from the IMU is collected based on the ROS driver. The IMU outputs raw acceleration measurements, angular velocity measurements, magnetic measurements, the absolute orientation in quaternion form.

• Data format:​

  • Timestamp - unit second - ROS timestamp ​

  • Quaternion :

    • Quaternion x​

    • Quaternion y

    • Quaternion z

    • Quaternion w

  • Acceleration:

    • Acceleration x (m/s^2)

    • Acceleration y (m/s^2)

    • Acceleration z (m/s^2)

  • Gyro:

    • Gyro x (rad/s)

    • Gyro y (rad/s)

    • Gyro z (rad/s)

  • More message types can be found here.

​

LIDAR

• Driver: The data from the LiDAR is collected based on the ROS driver. The data is saved into PointCloud2 Message.

• Data format (standard PCL point cloud format):

  • Timestamp - unit second - ROS timestamp 

  • X - unit meter - x coordinate in the local 3D Cartesian of each LiDAR frame.

  • Y - unit meter - y coordinate in the local 3D Cartesian of each LiDAR frame.

  • Z - unit meter - z coordinate in the local 3D Cartesian of each LiDAR frame.

  • R - unit - reflectivity value.

  • More message types can be found here.

​

Monocular Camera

• Driver: The data from the camera is collected based on the ROS driver, and is saved by sensor_msgs/Image Messages.

• Data format (standard PCL point cloud format):

  • Timestamp - unit second - ROS timestamp 

  • Image Message

  • More message types can be found here.

Reference System (GROUND TRUTH)

• Driver: The data from the SPAN-CPT is collected based on the ROS driver. 

• Data format:

  • Timestamp - unit second - ROS timestamp 

  • Latitude - unit degree- position in WSG84.

  • Longitude- unit degree- position in WSG84.

  • Altitude- unit degree- position in WSG84.

  • north_velocity- unit m/s - velocity in the local frame.

  • east_velocity- unit m/s - velocity in the local frame.

  • up_velocity- unit m/s - velocity in the local frame.

  • Roll - unit degree - orientation in the local frame.

  • Pitch - unit degree - orientation in the local frame.

  • Yaw- unit degree - orientation in the local frame.

  • More message types can be found here.

​

The SPAN system’s combined GNSS+IMU solution integrates the raw
inertial measurements with all available GNSS information to
provide the optimum solution possible, mitigated IMU error. The data of Novatel SPAN-CPT was collected using the software in Windows 7
and was saved in a .txt file. The data consists of standard GPS
time which could be transformed into the Ubuntu time.
The data format of SPAN-CPT: 
[Position, Velocity, Altitude, Pose]
Position port outputs latitude (in degree), longitude (in degree).
Velocity ( m/s ) is in the local Cartesian coordinates coordinate system aimed at SPAN-CPT.
Altitude is in the local Cartesian coordinates coordinate system aimed at SPAN-CPT in meters.
Pose port outputs roll in degrees, pitch in degrees, heading in degrees.