refactor(game_controller): only send ball PointStamped

to `game_controller_hsl` as the new [Gamecontroller] only expectes an
`(x, y)` coordinate.

[Gamecontroller]: https://github.com/RoboCup-HumanoidSoccerLeague/GameController/

Author: texhnolyze

src/bitbots_world_model/bitbots_ball_filter/bitbots_ball_filter/ball_filter.py

@@ -14,11 +14,9 @@
 from ros2_numpy import msgify, numpify
 from sensor_msgs.msg import CameraInfo
 from soccer_vision_3d_msgs.msg import Ball, BallArray
-from std_msgs.msg import Header
+from std_msgs.msg import Float32, Header
 from std_srvs.srv import Trigger
 from tf2_geometry_msgs import PointStamped, PoseStamped
-from soccer_model_msgs.msg import Ball as BallWithCovariance
-from std_msgs.msg import Float32
 
 from bitbots_ball_filter.ball_filter_parameters import bitbots_ball_filter as parameters
 
@@ -52,12 +50,10 @@ def __init__(self) -> None:
         self.ball_pose_publisher = self.create_publisher(
             PoseWithCovarianceStamped, self.config.ros.ball_position_publish_topic, 1
         )
-        self.ball_pose_with_covariance_publisher = self.create_publisher(
-            BallWithCovariance, "hsl_gamecontroller/ball_with_covariance", 1
-        )
-        self.ball_age_publisher = self.create_publisher(
-            Float32 , "hsl_gamecontroller/ball_age", 1
+        self.game_controller_ball_position_publisher = self.create_publisher(
+            PointStamped, "hsl_gamecontroller/ball_position", 1
         )
+        self.ball_age_publisher = self.create_publisher(Float32, "hsl_gamecontroller/ball_age", 1)
 
         # Create callback group
         self.callback_group = MutuallyExclusiveCallbackGroup()
@@ -256,7 +252,7 @@ def filter_step(self) -> None:
         # Increase covariance
         self.ball_state_covariance[:2, :2] += np.eye(2) * self.config.filter.covariance.process_noise
 
-        # Build message 
+        # Build message
         pose_msg = PoseWithCovarianceStamped()
         pose_msg.header = Header(
             stamp=Time.to_msg(self.get_clock().now()),
@@ -269,21 +265,19 @@ def filter_step(self) -> None:
         pose_msg.pose.pose.orientation.w = 1.0
         self.ball_pose_publisher.publish(pose_msg)
 
-        # Build message for Ball with Covariance
-        ball_msg = BallWithCovariance()
-        ball_msg.header = Header(
+        ball_position_msg = PointStamped()
+        ball_position_msg.point = msgify(Point, self.ball_state_position)
+        ball_position_msg.header = Header(
             stamp=Time.to_msg(self.get_clock().now()),
             frame_id=self.config.filter.frame,
         )
-        ball_msg.point.point = msgify(Point, self.ball_state_position)
-        covariance = np.zeros((6, 6))
-        covariance[:3, :3] = self.ball_state_covariance
-        ball_msg.point.covariance = covariance.flatten()
-        self.ball_pose_with_covariance_publisher.publish(ball_msg)
+        self.game_controller_ball_position_publisher.publish(ball_position_msg)
 
         # Build message for Ball age
         ball_age_msg = Float32()
-        ball_age_msg.data = np.float32(self.get_clock().now() - self.last_ball_time)
+        nanoseconds_since_last_ball = np.float32((self.get_clock().now() - self.last_ball_time).nanoseconds)
+        ball_age_msg.data = nanoseconds_since_last_ball / 1e9
+
         self.ball_age_publisher.publish(ball_age_msg)