Navigating with the navigation stack and hector_slam without an IMU

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Hello,

I am currently using hector_slam having no IMU installed.

I want to use the navigation stack. In combination with the hector_slam (hector_mapping) the robot shall navigate and move transport itself autonomously.

I am interested in two problems (and their solutions)

1. General question: My robot has no IMU installed and therefore does not publish any odometry information. Are odometry information required for the robot? Since hector_slam provides poses and tf's does a robot need additional odometry information provided by a physical IMU? If yes, why does it need them?
2. The navigation stack is well documented. In the rosgraph architecture for the navigation stack you see that odometry information is required. Do I need a physical IMU installed on my robot? Does hector_slam provide 'emulated, software-based' odometry? Using the hector_slams' published topics poseupdate or slam_out_pose and the transform can I 'calculate' my odometry and publish it? If yes, how would I do that?

I checked the ROS answers and yielded diverging anwers concerning this issue.

The question http://answers.ros.org/question/20445... is answered with 'you need odometry' to use the navigation stack.

The question http://answers.ros.org/question/73261... is answered with 'you can just forget about your robot's odometry, because hector_slam will provide it'

ROS version: kinetic OS: Ubuntu 16.04