Retire stub state_estimator; consumers use EKF /odometry/filtered

- state_estimator was an unimplemented stub (empty callbacks, never
  published /rov/state) - removed node, entry point, launch block
- motion_controller + mission_executor: /rov/state -> /odometry/filtered
  (the working robot_localization EKF output)
- Eliminates redundant/competing state estimators; single source of truth
- Verified: EKF publishes ~11Hz, both consumers subscribed

src/rov_control/rov_control/motion_controller.py

@@ -6,7 +6,7 @@ Implements depth hold and heading hold modes.
 
 Topics subscribed:
   /rov/cmd_vel       (geometry_msgs/Twist)   — velocity setpoint from mission planner
-  /rov/state         (nav_msgs/Odometry)     — current state from navigation stack
+  /odometry/filtered (nav_msgs/Odometry)  — fused state from EKF
   /rov/failsafe      (rov_interfaces/FailsafeStatus) — emergency override
 
 Topics published:
@@ -41,7 +41,7 @@ class MotionController(Node):
         self.cmd_sub = self.create_subscription(
             Twist, '/rov/cmd_vel', self.cmd_callback, 10)
         self.state_sub = self.create_subscription(
-            Odometry, '/rov/state', self.state_callback, 10)
+            Odometry, '/odometry/filtered', self.state_callback, 10)
         self.failsafe_sub = self.create_subscription(
             FailsafeStatus, '/rov/failsafe', self.failsafe_callback, 10)
 

src/rov_mission/rov_mission/mission_executor.py

@@ -21,7 +21,7 @@ Breadcrumb system:
   Used by return-to-safe to reverse the entry path safely.
 
 Topics subscribed:
-  /rov/state              (nav_msgs/Odometry)              — current position
+  /odometry/filtered      (nav_msgs/Odometry)      — fused state from EKF
   /rov/failsafe           (rov_interfaces/FailsafeStatus)  — safety override
 
 Topics published:
@@ -196,7 +196,7 @@ class MissionExecutor(Node):
         # ------------------------------------------------------------------
 
         self.create_subscription(
-            Odometry, '/rov/state',
+            Odometry, '/odometry/filtered',
             self._state_callback, 10)
 
         self.create_subscription(

src/rov_navigation/launch/navigation.launch.py

@@ -1,6 +1,6 @@
 """
 Navigation stack launch file.
-Launches: state_estimator, depth_node, robot_localization EKF
+Launches: depth_node, robot_localization EKF
 """
 
 from launch import LaunchDescription
@@ -25,13 +25,6 @@ def generate_launch_description():
             parameters=[ekf_config],
         ),
 
-        # State estimator
-        Node(
-            package='rov_navigation',
-            executable='state_estimator',
-            name='state_estimator',
-            output='screen',
-        ),
 
         # Depth node
         Node(

src/rov_navigation/launch/navigation.launch.py.bak

@@ -0,0 +1,43 @@
+"""
+Navigation stack launch file.
+Launches: state_estimator, depth_node, robot_localization EKF
+"""
+
+from launch import LaunchDescription
+from launch_ros.actions import Node
+from launch.actions import DeclareLaunchArgument
+from launch.substitutions import LaunchConfiguration
+from ament_index_python.packages import get_package_share_directory
+import os
+
+
+def generate_launch_description():
+    pkg_dir = get_package_share_directory('rov_navigation')
+    ekf_config = os.path.join(pkg_dir, 'config', 'ekf.yaml')
+
+    return LaunchDescription([
+        # EKF from robot_localization
+        Node(
+            package='robot_localization',
+            executable='ekf_node',
+            name='ekf_filter_node',
+            output='screen',
+            parameters=[ekf_config],
+        ),
+
+        # State estimator
+        Node(
+            package='rov_navigation',
+            executable='state_estimator',
+            name='state_estimator',
+            output='screen',
+        ),
+
+        # Depth node
+        Node(
+            package='rov_navigation',
+            executable='depth_node',
+            name='depth_node',
+            output='screen',
+        ),
+    ])

src/rov_navigation/rov_navigation/state_estimator.py

@@ -1,67 +0,0 @@
-#!/usr/bin/env python3
-"""
-State estimator node.
-Fuses IMU, depth, and (future) DVL data via robot_localization EKF.
-Publishes /rov/state as nav_msgs/Odometry.
-
-Topics subscribed:
-  /imu/data          (sensor_msgs/Imu)       — Xsens IMU
-  /mavros/imu/data   (sensor_msgs/Imu)       — ArduSub IMU (backup)
-  /rov/depth         (std_msgs/Float64)       — depth from pressure sensor
-
-Topics published:
-  /rov/state         (nav_msgs/Odometry)      — fused state estimate
-"""
-
-import rclpy
-from rclpy.node import Node
-from rclpy.qos import qos_profile_sensor_data
-from sensor_msgs.msg import Imu
-from nav_msgs.msg import Odometry
-from std_msgs.msg import Float64
-
-
-class StateEstimator(Node):
-    """Fuses sensor inputs into a single state estimate."""
-
-    def __init__(self):
-        super().__init__('state_estimator')
-
-        # --- Parameters ---
-        self.declare_parameter('use_xsens', True)
-        self.declare_parameter('use_mavros_imu', False)
-        self.use_xsens = self.get_parameter('use_xsens').value
-        self.use_mavros_imu = self.get_parameter('use_mavros_imu').value
-
-        # --- Subscribers ---
-        self.imu_sub = self.create_subscription(
-            Imu, '/imu/data', self.imu_callback, qos_profile_sensor_data)
-        self.depth_sub = self.create_subscription(
-            Float64, '/rov/depth', self.depth_callback, 10)
-
-        # --- Publishers ---
-        self.state_pub = self.create_publisher(Odometry, '/rov/state', 10)
-
-        self.get_logger().info('StateEstimator node started')
-
-    def imu_callback(self, msg: Imu):
-        """Handle incoming IMU data."""
-        # TODO: forward to EKF or process directly
-        pass
-
-    def depth_callback(self, msg: Float64):
-        """Handle incoming depth measurement."""
-        # TODO: incorporate depth into state estimate
-        pass
-
-
-def main(args=None):
-    rclpy.init(args=args)
-    node = StateEstimator()
-    rclpy.spin(node)
-    node.destroy_node()
-    rclpy.shutdown()
-
-
-if __name__ == '__main__':
-    main()

src/rov_navigation/setup.py

@@ -18,7 +18,6 @@ setup(
     zip_safe=True,
     entry_points={
         'console_scripts': [
-            'state_estimator = rov_navigation.state_estimator:main',
             'depth_node = rov_navigation.depth_node:main',
         ],
     },