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Robot

Robot messages provide information about the robot's pose, odometry, and physical state.

Message Types

Pose

Represents the robot pose.

Field Message Type Description
x_meters float x, y coordinates inside the Map relative to the map's specified origin.
y_meters float y coordinate inside the Map relative to the map's specified origin.
heading_radians float The heading of the robot in radians. Ranges from -PI to PI, with 0.0 pointing along the x-axis.
JSON Example
  {
    "xMeters": 2.5,
    "yMeters": 3.0,
    "headingRadians": 1.57
  }

PoseWithCovariance

A pose and a covariance matrix.

Field Message Type Description
pose Pose The robot pose.
covariance double repeated A 36-element array, which is a flattened 6×6 covariance matrix in row-major order. Each element represents the covariance between state variables (X, Y, Z, X-axis rotation, Y-axis rotation, Z-axis rotation).
JSON Example
  {
    "pose": {
      "xMeters": 2.5,
      "yMeters": 3.0,
      "headingRadians": 1.57
    },
    "covariance": []
  }

OdometryState

Represents the robot's odometry state.

Field Message Type Description
pose Pose The current robot pose.
twist Twist A message containing the linear and angular velocity of the robot. A positive linear velocity means the robot is moving forward in the direction of the Pose.heading, while a negative is opposite of the Pose.heading. A positive angular velocity means the robot is turning clockwise when looking from above, and negative is counter-clockwise when looking from above. If twist is 0, i.e. linear and angular velocities are 0, the robot is stationary.
JSON Example
  {
    "pose": {
      "xMeters": 2.5,
      "yMeters": 3.0,
      "headingRadians": 1.57
    },
    "twist": {
      "linearVelocity": 0.5,
      "angularVelocity": 0.2
    }
  }