IN Brief:
- UK Defence Innovation reported new details on 3 November about SEA and DAS technology demonstrated at Maritime Big Play off San Diego in October.
- SEA’s ADEPT models underwater acoustic communications conditions, while DAS’s AF-TAF coordinates task allocation across autonomous underwater vehicles.
- Both tools were demonstrated in an allied trial environment; procurement, fleet-scale deployment, and in-service qualification have not been announced.
Two British companies backed by UK Defence Innovation (UKDI) demonstrated software for underwater communications planning and autonomous-vehicle coordination at AUKUS Maritime Big Play off San Diego. SEA Ltd, based in Frome, presented its Acoustic Deployment Environment Planning Tool, while Basingstoke-based Decision Analysis Services Ltd (DAS) demonstrated the Autonomous Fleet Task Assignment Framework.
The demonstrations took place in October 2026, involving defence organisations and developers from the United Kingdom, United States, and Australia. UKDI published specific information on the two companies’ systems on 3 November. The trials showed their functions in an allied exercise setting; the government has not reported routine fleet deployment, qualification, or a new procurement order for either software tool.
SEA’s Acoustic Deployment Environment Planning Tool, known as ADEPT, addresses the difficulty of sending information through water. Radio signals that travel readily through air generally perform poorly over useful distances underwater, making acoustic communications an important option for submarines and autonomous underwater vehicles. Acoustic links, however, are affected by water temperature, salinity, depth, seabed conditions, and competing sound sources, which makes reliable communications planning a technical task in its own right.
ADEPT combines high-resolution environmental data with acoustic modelling to predict the likely performance of underwater communication links. These estimates can inform the positioning of vehicles and the planning of exchanges between them, particularly where acoustic propagation varies with depth and distance. The software provides planning information rather than a physical communications modem, and the accuracy of its predictions still depends on the environmental data used.
Environmental models cannot eliminate uncertainty. Conditions change in space and time, while vessels and other sources of noise can affect the signal received by an acoustic modem. Predicted communication performance therefore has to be compared with measurements made during trials and operations. SEA’s demonstration gave its team an opportunity to assess the tool against an operational environment and refine its modelling with additional observations from the exercise.
SEA’s acoustic-modelling work builds on capabilities that have supported Royal Navy applications for more than two decades. UKDI backing supported further development of ADEPT ahead of the San Diego exercise. The company expects the software to help plan underwater command-and-control arrangements as additional autonomous platforms enter maritime service, where the available communication capacity can be limited by propagation conditions and the time needed to exchange acoustic messages.
DAS addressed the related problem of deciding what those vehicles should do when a link is intermittent or unavailable. Its Autonomous Fleet Task Assignment Framework, AF-TAF, is designed to allow autonomous underwater vehicles to distribute tasks among themselves, rather than depend continuously on a central control station to direct every change. The software supports the allocation and reassignment of work as vehicles respond to changing mission conditions.
A group of underwater vehicles may have different sensors, endurance, or positions relative to a survey area. A centrally prepared mission plan can specify their initial roles, but an individual platform could need to change course or pause a task if it encounters an equipment problem or unexpected condition. A distributed task-assignment system is intended to let the group adjust work without requiring every decision to pass through a distant operator using a weak acoustic connection.
This approach shifts part of the coordination problem onto the vehicles themselves. The framework must represent the tasks available, the status of participants, and the rules governing what each vehicle is permitted to do. It also has to tolerate vehicles that cannot immediately share information with all other members of the group. DAS describes its solution as reducing reliance on continuous command-and-control orchestration, particularly where communications are degraded or denied.
DAS has also developed a simulation environment alongside AF-TAF. It allows planners to test different fleet compositions, task allocations, and operational scenarios before committing actual vehicles to a mission. Such results depend on the behaviour represented in the simulation, so testing with real vehicles and acoustic links remains important. Maritime Big Play offered an allied exercise setting in which to demonstrate the task-assignment concept.
ADEPT and AF-TAF address different technical constraints. SEA’s tool forecasts where underwater communications may be reliable; DAS’s framework distributes work among vehicles so that a task change need not always wait for central direction. UKDI describes separate demonstrations by the two companies and has not reported an integrated ADEPT–AF-TAF system test or joint procurement. Any combined application would require compatibility between the communications plan, vehicle autonomy software, and operational command rules.
The wider Maritime Big Play programme also tested common control arrangements and new underwater sensors. On 27 October the Ministry of Defence identified three sensor payloads that the UK would lead under AUKUS: synthetic aperture sonar, a deployable anti-submarine warfare sensor, and a deployable non-kinetic effector. Those payloads are a separate development programme from the ADEPT and AF-TAF software demonstrations, although all sit within the broader effort to coordinate underwater platforms.
SEA and DAS received support through the AUKUS Maritime Innovation Challenge, under which four selected companies share £3m to develop command, control, and cooperation capabilities for underwater systems. The 3 November account describes what the two UK-backed companies demonstrated in San Diego, without specifying further funding awards. Follow-on trials and customer integration decisions will establish whether either tool moves beyond demonstration into a defined naval programme.
