How to autonavigate in an unknown map

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I am not sure if I get your question correctly but I am going to answer it with my interpretation of your question.

What I understood from your question is you want to navigate in an unknown environment, the best way to do that would be using AMCL amd Gmapping package but in that case you need to provide target location to the navigation stack. However, there is another package called Frontier exploration which is used for exploring the environment. This is a sophisticated solution to your problem but there are simpler solutions as well. Since you have proximity sensors that you can use, you can easily write a simple "bug" planner and you will be able to move in the environment without map (target needs to be provided in this case as well).

Please note that if you want to use AMCL you need to convert the data from your sensors into sensor_msgs/LaserScan and publish it.