navsat_transform_node

From robot_localization's documentation for the navsat_transform_node:

navsat_transform_node takes as input a nav_msgs/Odometry message (usually the output of ekf_localization_node or ukf_localization_node), a sensor_msgs/Imu containing an accurate estimate of your robot’s heading, and a sensor_msgs/NavSatFix message containing GPS data. It produces an odometry message in coordinates that are consistent with your robot’s world frame. This value can be directly fused into your state estimate.

In the case of igvc-software, the 'world frame' is /odom.

Further explanation of the node can be obtained through their documentation.

This entry will serve to document the parameters used by the igvc-software repository in our implementation of the navsat_transform_node.

Subscribed Topics

• /fix [sensor_msgs/NavSatFix]
  • Provides a GPS estimate of the robot's latitude, longitude, and altitude.
• /odometry/filtered [nav_msgs/Odometry]
  • Contains a filtered estimate of the robots odometry. This includes estimates of the robot's position, orientation, linear velocity, and angular velocity.
• /tf [tf2_msgs/TFMessage]
  • Transform tree topic. Provides transforms to child_frame_id from header.frame_id.
• /tf_static [tf2_msgs/TFMessage]
  • Contains transform information relating the robot's static frames (assumed to never change and be valid for all timestamps). Topic msg contains geometry_msgs/TransformStamped[] array where each element expresses a transform from coordinate frame header.frame_id to the coordinate frame child_frame_id.

Published Topics

• /gps/filtered [sensor_msgs/NavSatFix]

  • sensor_msgs/NavSatFix message containing robot's world frame position as GPS coordinates.

• /odometry/gps [nav_msgs/Odometry]

  • Odometry message of robot's coordinates that are consistent with world frame.

Parameters

• freqeuency (float, 30)
  • desired hz for node.
• delay (float, 0)
  • The time, in seconds, to wait before calculating the transform from GPS coordinates to your robot’s world frame.
• magnetic_declination_radians (float, 0)
  • Difference between the magnetic north (what the IMU reads) and the true north. For more information, see here.
• two_d_mode (boolean, true)
  • Assumes we're in a planar environment.
• zero_altitude (boolean, true)
  • Sets altitude to 0.
• broadcast_utm_transform (boolean, true)
  • Publish broadcast between the UTM grid and the frame of the input odometry data (\odom).
• publish_filtered_gps (boolean, true)
  • Publish latitude and longitude of the robot position.
• use_odometry_yaw (boolean, false)
  • Use yaw angle from the input odom source.