1. Program Link to heading

Source Code

Branch: ros2

2. Workflow Link to heading

  1. The official bag file uses Velodyne LiDAR. Modify the sensor settings in the /config/params.yaml file in the ros2 branch.

    # Sensor Settings
    sensor: velodyne                               # lidar sensor type, can be 'velodyne', 'ouster', or 'livox'
    N_SCAN: 16                                   # number of lidar channels (e.g., Velodyne/Ouster: 16, 32, 64, 128, Livox Horizon: 6)
    Horizon_SCAN: 1800                            # lidar horizontal resolution (Velodyne: 1800, Ouster: 512, 1024, 2048, Livox Horizon: 4000)
    downsampleRate: 1                            # default: 1. Downsample your data if it’s too large

  2. The official bag files come in different formats. I’ve downloaded the campus and park datasets. Depending on which bag file you are running, modify the topics and IMU Settings in the /config/params.yaml file in the ros2 branch.

    (1) park_dataset

    # Topics
pointCloudTopic: "/points_raw"                   # Point cloud data
imuTopic: "imu_raw"                              # IMU data
# IMU Settings
extrinsicRot:    [-1.0,  0.0,  0.0,
                    0.0,  1.0,  0.0,
                    0.0,  0.0, -1.0 ]
extrinsicRPY: [ 0.0,  1.0,  0.0,
                    -1.0,  0.0,  0.0,
                    0.0,  0.0,  1.0 ]

    (2) campus_dataset

    # Topics
pointCloudTopic: "/points_raw"                   # Point cloud data
imuTopic: "/imu_correct"                         # IMU data
# IMU Settings
extrinsicRot:    [1.0,  0.0,  0.0,
                    0.0,  1.0,  0.0,
                    0.0,  0.0, 1.0 ]
extrinsicRPY: [ 1.0,  0.0,  0.0,
                0.0,  1.0,  0.0,
                0.0,  0.0,  1.0 ]

3. Issues Link to heading

The official bag files are only available for ROS1, and testing on ROS2 requires converting the bags. The following two methods were tested for conversion:

  1. rosbags

    Install and test:

    apt-get update
apt-get install python3-pip
pip install rosbags
rosbags-convert --src <path_to_rosbag1_filename> --dst <path_to_ros2bag_filename>  # Convert the bag file

    Result: After converting with rosbags, the IMU frequency dropped from 500Hz to 250Hz, making it unusable.

  2. ros1_bridge

    Install and test: I created a Docker image, link

    Result: No frequency drop, works fine.

4. Testing Link to heading

The process is reproducible.