Sensor Coordinate Systems

This section describes the coordinate system for each sensor in MORAI simulator and how to verify the sensor output data.

IMU Coordinate System

• Measure the values of a 6-degree-of-freedom system.
  ( X, Y, Z, roll, pitch, yaw )

• IMU Sensor Output Data

  • linear_acceleration

    • X : X-axis acceleration in IMU sensor (Forward +, Backward -)

    • Y : Y-axis acceleration in IMU sensor (Left +, right -)

    • Z : Z-axis acceleration in IMU sensor (UP +, Down -)

  • angular_velocity

    • X : X-axis angular velocity in IMU sensor (Roll)

    • Y : Y-axis angular velocity in IMU sensor (Pitch)

    • Z : Z-axis angular velocity in IMU sensor (Yaw)

    • (CounterClockwise +, Clockwise -)

  • orientation

    • X : Quaternion X vector

    • Y : Quaternion Y vector

    • Z : Quaternion Z vector

    • w : Quaternion w vector

GPS Coordinate System

• Follow UTM Coordinate system

  • UTM52N (WGS84)
    EPSG:32652
    +proj=utm +zone=52 +ellps=WGS84 +datum=WGS84 +units=m +no_defs

Velodyne LiDAR Coordinate System

• Forward : y

• Right : x

• Up : z
  

• Velodyne LiDAR Manual Information

• ROS Axis Orientation

  • Once you check the standard units of ROS in REP 103 (ROS Enhancement Proposals), you will know the basic units used in ROS. ( https://www.ros.org/reps/rep-0103.html#id14 )

  • Forward : x

  • Left : y

  • Up : z
    

• Use ROS Velodyne_driver
  When outputting data via ROS Velodyne_driver, it is represented in the default ROS coordinate system rather than the original Velodyne coordinate system. The Velodyne LiDAR coordinates change from (forward: y, right: x, up: z) to (forward: x, left: y, up: z).
  

• Comparison between Veloview and ROS RViz using the simulator.