The technology has been developed by US company Leidos and was installed on a 9.75 metre work boat for the at-sea tests.
The testing was conducted as part of the development of the US Defense Advanced Research Projects Agency's (DARPA) Anti-Submarine Warfare Continuous Trail Unmanned Vessel (ACTUV), with the workboat acting as a "surrogate" for the ACTUV during the trials.
Leidos says that its strategy to evaluate the prototype autonomy system for COLREGS compliance includes both simulation and at-sea testing, with its team having now completed approximately 26,000 simulation runs of the system.
Testing of COLREGS compliance involved the installed workboat and one interfering vessel in a variety of meeting, crossing, overtaking and transit scenarios in both simulation and on the water test events.
During a recent on the water test event, Leidos says that the surrogate boat autonomously navigated through narrow channels avoiding navigation aids and submerged hazards. The boat also safely avoided surface ships it encountered along the route, satisfying COLREGS requirements in completely unscripted events.
During 42 days of at-sea testing that included 101 individual scenarios, the autonomy system directed course and speed changes of the surrogate vessel to stay safely outside a 1-km standoff distance from the interfering vessel.
Leidos says that the test programme demonstrated the ability of the ACTUV autonomy system to successfully manoeuver and avoid collision with another vessel, and that this will pave the way for follow-on testing involving multiple interfering contacts and adversarial behaviour on the part of interfering vessels.
While continuing to use the surrogate vessel to test the ACTUV software and sensors, construction of Sea Hunter, the first ACTUV vessel, is already progressing at Christensen Shipyard in Clackamas, Oregon.
Sea Hunter is scheduled to launch in late summer 2015 and begin testing in the Columbia River shortly thereafter.