Covert path planning in unknown environments with known or suspected sentry location

This paper describes an approach for solving a visibility-based covert path planning problem. It is an extension to our research on covert robotics which aims to create robots with the ability to achieve different covert navigation missions. A promising method is presented that allows a mobile robot in a complex, initially unknown environment to discover a path to a nominated destination with minimum exposure to sentries' at known locations within the same environment. The sentries' locations are known initially, suspected, or discovered during navigation. The presented method estimates a cost value at each non-obstacle location that represents a risk of being visible, given the accumulated map knowledge. A global covert path is generated by propagating the estimated cost values using the distance transform algorithm. The approach has been evaluated on both simulated and real environments. A number of test cases are presented; each shows a generated path with considerable covertness compared to a short path (but perhaps risky) to the same destination.