diff --git a/README.md b/README.md
index 8440554..0db8ae7 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,49 @@
-tum_simulator ported to Hydro
+tum_simulator on Indigo
=============
+
+These packages are used to simulate the flying robot Ardrone in ROS environment using gazebo simulator. Totally they are 4 packages. Their functions are descript as below:
+
+1. cvg_sim_gazebo: contains object models, sensor models, quadrocopter models, flying environment information and individual launch files for each objects and pure environment without any other objects.
+
+2. cvg_sim_gazebo_plugins: contains gazebo plugins for the quadrocopter model. quadrotor_simple_controller is used to control the robot motion and deliver navigation information, such as: /ardrone/navdata. Others are plugins for sensors in the quadrocopter, such as: IMU sensor, sonar sensor, GPS sensor.
+
+3. message_to_tf: is a package used to create a ros node, which transfers the ros topic /ground_truth/state to a /tf topic.
+
+4. cvg_sim_msgs: contains message forms for the simulator.
+
+Some packages are based on the tu-darmstadt-ros-pkg by Stefan Kohlbrecher, TU Darmstadt.
+
+How to install the simulator:
+
+1. Create a workspace for the simulator
+
+ ```
+ mkdir -p ~/tum_simulator_ws/src
+ cd ~/tum_simulator_ws/src
+ catkin_init_workspace
+ ```
+2. Download dependencies
+
+ ```
+ git clone https://github.com/AutonomyLab/ardrone_autonomy.git # The AR.Drone ROS driver
+ git clone https://github.com/occomco/tum_simulator.git
+ cd ..
+ rosdep install --from-paths src --ignore-src --rosdistro indigo -y
+ ```
+3. Build the simulator
+
+ ```
+ catkin_make
+ ```
+4. Source the environment
+
+ ```
+ source devel/setup.bash
+ ```
+How to run a simulation:
+
+1. Run a simulation by executing a launch file in cvg_sim_gazebo package:
+
+ ```
+ roslaunch cvg_sim_gazebo ardrone_testworld.launch
+ ```
diff --git a/cvg_sim_gazebo/urdf/quadrotor.urdf.xacro b/cvg_sim_gazebo/urdf/quadrotor.urdf.xacro
index 158639a..6f0c637 100644
--- a/cvg_sim_gazebo/urdf/quadrotor.urdf.xacro
+++ b/cvg_sim_gazebo/urdf/quadrotor.urdf.xacro
@@ -7,7 +7,7 @@
xmlns:xacro="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface">
-
+
diff --git a/cvg_sim_gazebo/urdf/quadrotor_base.urdf.xacro b/cvg_sim_gazebo/urdf/quadrotor_base.urdf.xacro
index bdc5c23..692fdb2 100644
--- a/cvg_sim_gazebo/urdf/quadrotor_base.urdf.xacro
+++ b/cvg_sim_gazebo/urdf/quadrotor_base.urdf.xacro
@@ -6,7 +6,7 @@ xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
xmlns:xacro="http://ros.org/wiki/xacro"
>
-
+
diff --git a/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro b/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro
index 99e7bbd..f2465a5 100644
--- a/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro
+++ b/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro
@@ -9,36 +9,36 @@ xmlns:xacro="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface">
-
+
-
+
-
+
-
+
-
+
diff --git a/cvg_sim_gazebo/urdf/sensors/generic_camera.urdf.xacro b/cvg_sim_gazebo/urdf/sensors/generic_camera.urdf.xacro
index 3e88c19..8a02b7f 100644
--- a/cvg_sim_gazebo/urdf/sensors/generic_camera.urdf.xacro
+++ b/cvg_sim_gazebo/urdf/sensors/generic_camera.urdf.xacro
@@ -93,7 +93,7 @@ xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
true
- PR2/Blue
+ Gazebo/Blue
diff --git a/cvg_sim_gazebo_plugins/include/hector_gazebo_plugins/diffdrive_plugin_6w.h b/cvg_sim_gazebo_plugins/include/hector_gazebo_plugins/diffdrive_plugin_6w.h
index 31fc3a7..e43f09d 100644
--- a/cvg_sim_gazebo_plugins/include/hector_gazebo_plugins/diffdrive_plugin_6w.h
+++ b/cvg_sim_gazebo_plugins/include/hector_gazebo_plugins/diffdrive_plugin_6w.h
@@ -27,13 +27,13 @@
#include