Sensors fusion for approximating position is not working

[nag92]

Please provide the following information:

• OS: 20.04
• ROS Distro: Noetic
• Built from source or installed:
• Package version: neotic
• Real hardware or simulation: simulation

Expected behaviour

The TF and Odom should show the approximate position of the warthog.

Actual behaviour

The odom position is very different form the gazebo position. The robot pose error increase as the robot is driven around. The error
becomes very large when attempting to turn. It seems to be a error with the EKF, I think the IMU is not running to sensors fusion cannot update the odom.

To Reproduce
Provide the steps to reproduce:

 roslaunch warthog_gazebo empty_world.launch 

Other notes
the imu topics is listed but not publishing