U.S. Navy Wants Unmanned Vessels to Make VHF Calls

As part of the U.S. Navy’s accelerating investment in unmanned systems, it is seeking proposals for an automated “bridge-to-bridge radio for unmanned surface vehicles” – a system that would give unmanned vessels the ability to talk to human mariners and make passing arrangements over VHF. The text of a newly-issued RFP indicates that the service has its Sea Hunter autonomous vessel in mind as a testbed platform.

The Rules of the Road (COLREGS) give clear instructions for encounters between two vessels in sight when risk of collision exists, but they do not specify what happens when three or more vessels are interacting at the same time. In everyday commerce, mariners deal with traffic of all kinds by communicating with other ships over VHF. No current unmanned surface vessel (USV) is equipped to conduct and act upon bridge-to-bridge voice communications.

According to the Navy, off-the-shelf technologies exist to convert voice signals to into text and to convert text to machine-usable meaning. The Navy’s Unmanned Maritime Systems Program Office is looking for a complete solution that will enable a USV to act much like a human mariner – that is, to understand voice radio transmissions, incorporate their meaning into its world model, develop appropriate maneuvering plans, and respond via voice over bridge-to-bridge radio. It will accept partial solutions to the problem, but ideally it is seeking a complete package.

The acquisition plan calls for three phases. The first, a proof-of-concept phase, calls for a demonstrator system that can understand simple phrases used to make passing arrangements. At a minimum, the end product for the first phase would have to recognize common bridge-to-bridge calls as made by native English speakers. As an example, the RFP used the phrase “[USV] Sea Hunter, this is Sun Princess; propose a port-to-port passage.”

The second phase calls for an integrated prototype connected to a VHF radio. The phase two device must have extended functionality to recognize English spoken by non-native speakers, and it must be able to generate English phrases of its own to reply to calls. Phase two calls for (but doesn’t require) adding functions to integrate the system with an autonomous vessel’s COLREGS reasoning and world model.

In phase three, the selected contractor will integrate the system with an autonomous navigation reasoning engine. It will also help the Navy transition the technology to real-world use. The technology will be used in the Navy’s Medium Unmanned Surface Vehicle (MUSV) program, the Large Unmanned Surface Vehicle (LUSV) program and possibly other USV programs. The RFP also mentioned the potential for civilian applications aboard unmanned merchant vessels and aboard manned pleasure craft “as an aid to a human operator.”

Though not always used in practice, the ship’s whistle is the legally recognized system for making passing arrangements under COLREGS.