Unmanned marsupial sea-air system for object recovery

This paper presents preliminary results obtained from a cooperative heterogeneous system consisting of an unmanned surface marine vehicle (USV) and an unmanned aerial vehicle (UAV). The envisioned scenario for this marsupial system is unmanned recovery of objects floating at the sea surface. The specific mission that is addressed in this paper includes the following phases: coarse approach where the USV approaches the object area using navigation filter based on GPS measurements; fine approach where the UAV tracking the USV sends relative distances between the USV and the object which is visible in the UAV´s field of view; and tugging where the USV takes the object to safety after the initial contact has been achieved. The paper describes the ROS-based control architecture, presents simulation results, and addresses control issues related to obtaining measurements from two sources with different variances.