Added small docs

README.md

@@ -1,7 +1,33 @@
 ## Robot Package Template
 
-This is a GitHub template. You can make your own copy by clicking the green "Use this template" button.
+### Installation
+```
+sudo apt-get install ros-iron-ros-gz ros-iron-robot-state-publisher
+```
 
-It is recommended that you keep the repo/package name the same, but if you do change it, ensure you do a "Find all" using your IDE (or the built-in GitHub IDE by hitting the `.` key) and rename all instances of `my_bot` to whatever your project's name is.
+### Execution
+```
+ros2 launch sensor_sim launch_sim.py
+```
 
-Note that each directory currently has at least one file in it to ensure that git tracks the files (and, consequently, that a fresh clone has direcctories present for CMake to find). These example files can be removed if required (and the directories can be removed if `CMakeLists.txt` is adjusted accordingly).
+### Changing the position of lidar and camera
+
+In `/description/lidar.xacro` there is a block looking like this:
+
+```
+<joint name="laser_joint" type="fixed">
+    <parent link="chassis"/>
+    <child link="laser_frame"/>
+    <origin xyz="-1.1 0.0 1.0" rpy="0 0 0"/>
+</joint>
+```
+Modifying the origin key changes the position of the lidar (relative to the center of the front axle of the car). The simulation needs to be restarted.
+There is a similar block in `/description/bbox_camera.xacro` looking like
+```
+<joint name="camera_joint" type="fixed">
+    <parent link="laser_frame"/>
+    <child link="camera_link"/>
+    <origin xyz="0 -0.2 0" rpy="0 0 0"/>
+</joint>
+```
+Modifying the origin yields the same result, but the camera is relative to the position of the lidar.

launch/launch_sim.py

@@ -35,12 +35,6 @@ def generate_launch_description():
         parameters=[params]
     )
 
-    node_joint_state_publisher = Node(
-        package='joint_state_publisher',
-        executable='joint_state_publisher',
-        parameters=[{'use_sim_time': True}]
-    )
-
     gazebo = IncludeLaunchDescription(
                 PythonLaunchDescriptionSource([os.path.join(
                     get_package_share_directory('ros_gz_sim'), 'launch', 'gz_sim.launch.py')]),
@@ -95,7 +89,6 @@ def generate_launch_description():
             default_value='-45',
             description='Lower limit of FOV of lidar'),
         node_robot_state_publisher,
-        node_joint_state_publisher,
         gazebo,
         spawn_entity,
         bridge,