Added ground bridge documentation (nasa#568)

communications/ground_dds_ros_bridge/readme.md

@@ -1,3 +1,50 @@
-\page dds_ros_bridge DDS ROS Bridge
+\page ground_dds_ros_bridge Ground DDS ROS Bridge
 
-The DDS ROS Bridge acts like a translator between the ground data system (GDS) and flight software (FSW). It receives rapid messages from GDS and converts them to ros messages and vise versa. It also sends compressed file acknowledgements upon receiving compressed files. Furthermore, it is responsible for reading in the command configuration file and sending it in a rapid command configuration message to GDS.
+The ground DDS ROS bridge acts like a translator between DDS and ROS. It listensto DDS telemetry coming from the robot and converts it to ROS messages.
+Currently it only supports converting the access control state, guest science
+data, dock camera compressed image, navigation camera compressed image, science
+camera compressed image, and the robot position messages. It also converts
+messages published on the ros command topic to a dds command and publishes them
+on the dds command topic. Please note that as of now, the ground dds ros bridge
+can only connect to one robot.
+
+The ground bridge will need to be configured for your specific situation. Please
+see the next section for more information.
+
+# Configuration
+
+The ground dds ros bridge config file can be found here:
+
+    $ASTROBEE_WS/src/astrobee/config/communications/ground_dds_ros_bridge.config
+
+The following sections explain what may need to be changed in the file.
+
+## Connecting Robot
+
+The ground bridge needs to know the name of the robot you want to connect to.
+The default is Bumble. If you need to change this, please open the config file
+and find the connecting_robot variable. Please change it to the name of the
+robot you wish to connect to. Make sure to capitalize the first letter of the
+name.
+
+## Domain id
+
+The domain id needs to be either 37 for simulation or 23 for space. The default
+is set to 37.
+
+## Namespace
+
+If you are running the ground bridge in simulation, you will probably want to
+use the namespace feature. When set to true, the ground bridge will publish
+messages received over DDS to ros using the robot name as the namespace. This
+will allow you to distigush topics/messages published by the core flight
+software versus topics/messages published by the ground bridge. By default, it
+is set to false.
+
+# Running the Ground DDS ROS Bridge
+
+The ground bridge is not run by default in simulation. To run it, you'll need to
+set the ASTROBEE_CONFIG_DIR environment variable. In a terminal with the
+astrobee setup sourced, run:
+
+ASTROBEE_CONFIG_DIR=$ASTROBEE_WS/src/astrobee/config/ rosrun ground_dds_ros_bridge ground_dds_ros_bridge_node