Isaac Ros VSlam localization and imu questions

Hello guys,

Here’s the setup I experimented ISAAC Visual Slam on.

  • Xavier AGX (Jetpack 5.0.2)
  • Ubuntu 20.04
  • ROS Foxy
  • ISAAC Visual Slam DP 1.1 (installed from source)
  1. Having localization_n_mapping set to true, I suddenly get an error that looks like: [Timestamp] Error addr X. What does this error mean/what causes it? These errors are printed randomly without affecting the flow of mapping/vo.

Error x screenshot 1

  1. When the camera_link tf gets sudden jumps (cause by incorrect localization - 2-3 meters high) and I try to do the localization in a known point (by using visual_slam/load_map_and_localize service on a stored map), in console it shows that the localization was done successfully (and it prints the right coordinates). At the same time, nothing happens and an error is also printed: poseGraph->Reindex() failed. What exactly causes this error? Any fix for this?
    If elbrus is reset first (by using visual_slam/reset service) and I do the exact same steps, I will get the expected behavior: load map and localize successfully.

  2. If the camera is not perpendicular to the ground, what’s the correct way to set the gravitational_force vector on launch? Here’s how the parameters were set for VIO tests (with camera slightly pointing to the ground):

                    'enable_imu': True,
                    'map_frame': 'map',
                    'odom_frame': 'odom',   
                    'base_frame': 'camera_link',
                    'input_left_camera_frame': 'camera_infra1_frame',
                    'input_right_camera_frame': 'camera_infra2_frame',
                    'input_imu_frame': 'camera_imu_optical_frame',
                    'path_max_size': 5000,
                    'gravitational_force': [0.8429, 6.0940, 8.5260]

And also here’s how the gravitational vector looks like:

Is that the expected behavior for the gravity vector?

  1. Considering that the screenshot above illustrates the expected behavior, how can the gravitational vector be used to determine the real orientation of the camera_link (if the camera points to the ground, the camera_link tf should do the same) ?

Thank you and have a nice day!


Could you please share your launch file? It looks like there are additional nodes in the launch file which produces the “X” error

To set the gravity vector, you need to fill out the vector which reports the orientation of imu in the base_link frame (x - forward, y - left, and z - up). See the code here.

Hi there,

Thank you for response! Here’s the launch file for the first question above. The camera is not launched by using the file below. I do it separately.

import launch
from launch_ros.actions import ComposableNodeContainer
from launch_ros.descriptions import ComposableNode

def generate_launch_description():
    """Launch file to bring up visual slam node standalone."""
    visual_slam_node = ComposableNode(
        remappings=[('stereo_camera/left/image', '/camera/infra1/image_rect_raw'),
                    ('stereo_camera/left/camera_info', '/camera/infra1/camera_info'),
                    ('stereo_camera/right/image', '/camera/infra2/image_rect_raw'),
                    ('stereo_camera/right/camera_info', '/camera/infra2/camera_info'),
                    ('visual_slam/imu', '/camera/imu')
                    'enable_rectified_pose': True,
                    'denoise_input_images': False,
                    'rectified_images': True,
                    'enable_debug_mode': False,
                    'debug_dump_path': '/tmp/elbrus',
                    'enable_slam_visualization': True,
                    'enable_landmarks_view': True,
                    'enable_observations_view': True,
                    'enable_localization_n_mapping': True,
                    'enable_imu': True,
                    'map_frame': 'map',
                    'odom_frame': 'odom',   
                    'base_frame': 'camera_link',
                    'input_left_camera_frame': 'camera_infra1_frame',
                    'input_right_camera_frame': 'camera_infra2_frame',
                    'input_imu_frame': 'camera_imu_optical_frame',
                    'path_max_size': 5000,
                    'gravitational_force': [0.8429, 6.0940, 8.5260]

    visual_slam_launch_container = ComposableNodeContainer(

    return launch.LaunchDescription([visual_slam_launch_container])

I was curious if the picture above represents the expected results. Also, what about **poseGraph->Reindex() ** error? Do you have any idea what causes it?

Thank you once again!

How did you calculate the values that you’ve specified for the gravitational_force parameter? It seems that the norm of that vector is 10.5, which doesn’t match the expected value of g=9.81 m/s^2.

You mentioned earlier that your camera is not aligned to the ground plane. However, in your RViz screenshot, it appears that the tf2 tree is broken and that the camera frame is aligned to the ground plane.

Could you provide some more information about how the frames in your transform tree are specified?

We’re still investigating the poseGraph->Reindex() error you described.