.. _carla_lab:

Carla 
=========

The **Carla** example in **Ufil** demonstrates one of the framework's advanced use cases in a simulated environment using the CARLA simulator.  
It consists of multiple packages and is included in the ``ufil_examples`` module.

This scenario illustrates how a complete infrastructure-based localization system, described in the :ref:`Complex Scenario <complex_scenario>`, can be executed using a high fidelity simulator.

Scenario
--------

The scenario is a highway segment in **TOWN 5**, where vehicles are equipped with simulated V2I functionality and broadcast CAM messages. A outdoor sensor node is installed roadside, facing the highway, while the sensitive surface layer (SSL) is simulated in the lanes using a co-simulation based on vehicle ground-truth data. Their fields of view partially overlap.

.. image:: /images/highway_scenario.png
   :width: 400px
   :align: center
   :alt: Illustration of the scenario.

The setup in the CARLA testbed looks like this:

.. image:: /images/carla_example.png
   :width: 400px
   :align: center
   :alt: Illustration of the CARLA lab scenario.

Usage
-----

1. **Starting the Example**
   
Launch the full CARLA simulation and Ufil stack with:

.. code-block:: bash

   ros2 launch ufil_examples carla-highway.launch.xml

The RViz visualization should appear as follows:

.. image:: /images/carla_visualization.png
   :width: 400px
   :align: center
   :alt: RViz showing Ufil visualization in CARLA

2. **Playing the Dataset**

In a second terminal, play back the prerecorded bag file for TOWN 5 to replay all sensor data and trigger the perception pipeline.  
Using a higher clock frequency improves timestamp accuracy.

.. code-block:: bash

   ros2 bag play ./260223_highway/ --topics /carla/lidar /ssl/ssl_1/map  /ssl/ssl_1/map_update /carla/objects /carla/actor_list /carla/rgb_view_left/image /carla/rgb_view_right/image --clock 300

The visualization will now display the tracking in action and produce output like this:

.. image:: /images/carla_running.png
   :width: 400px
   :align: center
   :alt: RViz showing Ufil tracking in the CARLA lab scenario

Dataset
-------

The dataset used for this example is currently **redacted** and will be made available after the paper is accepted at the corresponding venue.