Frontseat–Backseat Control Architecture for AUVs: Enabling Mission-Specific Autonom

The increasing complexity of Autonomous Underwater Vehicle (AUV) missions demands specialised behaviours that are difficult to integrate into a general-purpose vehicle
controller without sacrificing operational flexibility. A frontseat-backseat control paradigm addresses this challenge by allowing a secondary backseat controller to assume partial vehicle control for mission-specific tasks, while the primary frontseat controller maintains vehicle safety and essential operation. This paper presents the frontseat-backseat architecture developed at the National Oceanography Centre (NOC) for use on board its fleet of marine autonomous vehicles, built around the Onboard Control System (OCS) as the frontseat. Central to this architecture is the Backseat Gateway: a dedicated interface that manages all frontseat–backseat communication, enforces operator-configured
safety constraints on backseat manoeuvre requests, and regulates the control handover process. The architecture is validated through simulated thermocline tracking missions using the NOC Gazebo Simulator, demonstrating that a backseat controller can direct intelligent, real-time mission-specific manoeuvres without requiring any modification to the independent frontseat controller.