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Testing and Validation

Link to module repo: odom_gnss_fusion

For build instructions (including how to enable test publishers with BUILD_TESTING=ON), see the repository README.

Test Publisher

The package includes a test publisher that simulates both sensor inputs from a single consistent ground-truth trajectory. A body-frame base velocity is integrated into a global pose. The odometry output published on /odom_velocity adds configurable offset and noise to the body-frame velocity. The GNSS output published on /gnss_pose adds configurable noise to the global-frame ground-truth pose. The node also publishes the ground-truth global-frame velocity on /global_velocity for debugging and visualization. Furthermore, the node broadcasts a static identity TF from base_link to gnss_link.

ros2 run odom_gnss_fusion fusion_test_publisher

Parameters

Base velocity (ground truth, body frame):

Parameter Type Default Description
base_xd double 1.0 Forward velocity (m/s)
base_yd double 0.0 Lateral velocity (m/s)
base_phid double 0.1 Yaw rate (rad/s)

Odometry output (/odom_velocity):

Parameter Type Default Description
odom_publish_frequency_hz double 1000.0 Publication rate (Hz)
odom_offset_xd double 0.1 Systematic X velocity offset (m/s)
odom_offset_yd double -0.05 Systematic Y velocity offset (m/s)
odom_offset_phid double 0.01 Systematic yaw rate offset (rad/s)
odom_noise_stddev_xd double 0.005 X velocity noise standard deviation (m/s)
odom_noise_stddev_yd double 0.005 Y velocity noise standard deviation (m/s)
odom_noise_stddev_phid double 0.005 Yaw rate noise standard deviation (rad/s)

GNSS output (/gnss_pose):

Parameter Type Default Description
gnss_publish_frequency_hz double 10.0 Publication rate (Hz)
gnss_noise_stddev_x double 0.2 X position noise standard deviation (m)
gnss_noise_stddev_y double 0.2 Y position noise standard deviation (m)
gnss_noise_stddev_phi double 0.05 Yaw noise standard deviation (rad)
gnss_stale bool false Whether to publish GNSS data or not

Frame IDs:

Parameter Type Default Description
map_frame_id string "map" Header frame ID for GNSS pose
gnss_frame_id string "gnss_link" GNSS sensor frame for static TF
base_link_frame_id string "base_link" Robot base frame for static TF

Note

For real deployments where the GNSS antenna is not at the robot center, broadcast the actual transform instead of using the test publisher's identity TF: 

ros2 run tf2_ros static_transform_publisher 0.5 0.0 1.2 0 0 0 base_link gnss_link

Validation Procedures

Noise Filtering

  1. Start the test publisher with high GNSS noise and low odometry noise: 
    ros2 run odom_gnss_fusion fusion_test_publisher --ros-args \
  -p gnss_noise_stddev_x:=1.0 -p gnss_noise_stddev_y:=1.0
  2. Set \(\tau = 1.0\) (aggressive filtering).
  3. Record both /gnss_pose and /observed_pose (e.g. with ros2 bag record).
  4. Verify the observed output is significantly smoother than the raw GNSS input.

Odometry Bias Correction

  1. Start the test publisher with a systematic odometry offset: 
    ros2 run odom_gnss_fusion fusion_test_publisher --ros-args -p odom_offset_xd:=0.5
  2. Set \(\tau = 0.3\).
  3. Verify the observed pose tracks the GNSS trajectory rather than diverging with the biased odometry.