Autonomous systems – the future of Royal Navy mine warfare

The Integrated Review confirmed what had been rumoured for some time – the RN will gradually replace its remaining 13 minehunters with remotely operated or autonomous systems based on small boats. This in-depth article considers the developments that are underway and the advantage and risks that come with this innovation.

The plan at present is for the six surviving Hunt class MCMVs to be retired between 2029 and 2031 while the seven Sandown class will be phased out sooner, although more gradually between 2023 and 2031. However, the pace of ship retirements could be accelerated if Maritime Autonomous Systems (MAS) exceed current expectations.

The RN’s Mine countermeasures and Hydrographic Capability (MHC) programme is a complex project that began in 2014 with the intention to deliver fully autonomous minehunting by 2033. The future of the hydrographic vessels is unclear although the intention is that autonomous surveying systems will be deployed on the SVHOs (HMS Echo and Enterprise) from the mid-2020s. There is also an aspiration to replace the survey ships, probably in the early-mid 2030s, although the Defence Command Paper does not mention this. MHC has adopted a cautious, phased approach, to reduce risk using a series of technology demonstrators, trials and studies and has two core programmes; project WILTON and MMCM.

WILTON

Initially tasked with delivering a UK-based autonomous Route Survey (RTSV) capability, the Wilton team are part of the First MCM Squadron based at Faslane and will provide a low-risk pathfinder for the RN using MAS. This will initially be deployed on the Clyde but the system is road-transportable and able to cover the whole of Scotland and the north of England. RTSV involves regular mapping of the seabed in detail so that any newly laid object can quickly be spotted and investigated. The approaches to the Clyde are especially sensitive, being the entry and exit route for the nuclear deterrent submarines. RTSV is an ideal first task for MAS, being predictable, repetitive and much cheaper than employing crewed vessels. Wilton is equipped with 3 boats that can carry REMUS 100 and 600 small-medium UUVs, Side-scan sonars and M500 ROVs.

The Wilton team is small, numbering around 15 mine warfare personnel and once operational, are expected to provide 100 days of RTSV tasking and a further 60 days of trials per year. The unit is also tasked with developing organisational structures, doctrine and establishing standard operating procedures as well as supporting trials and evaluation for future RN MAS.

Sweep

Besides RTSV, the RN now has an autonomous Combined Influence Sweeping (CIS) capability. Unlike legacy ’sweeping’ which involved towing wires to cut mines adrift from the sinker units that held them on the sea bed, modern sweeping uses electronic means to deceive mines to activate by simulating the acoustic, magnetic, pressure or electrical signatures of a ship.

The ATLAS Remote Combined Influence Minesweeping System (ARCIMS) was delivered to the RN in 2018 and provides this capability. The USV can tow a variety of effectors including; 3 x Coil Auxiliary Boats (CAB), a magnetic electrode sweep, a hydrosounder wideband sound source, an acoustic source generator that uses water flow to create noise and an echo repeater that simulates active sonar echoes from a ship’s hull. Collectively these form the Sweep Module which can be used in either Target Setting Mode (TSM) or Mine Setting Mode (MSM). The system is portable in 4 ISO containers that store the USV, Sweep Module and Portable Operations Centre (POC). Based on RNMB Hussar, the RN’s Maritime Autonomous Systems Trials Team (MASTT) has conducted cold weather trials with the system in Halifax Canada (Jan 2020) and hot weather trials in the Gulf (Oct 2020).

MMCM

The centrepiece of the RN’s moves toward autonomous mine hunting is the Anglo / French Maritime Mine Countermeasures (MCMM) / SLAMF (Système de Lutte Anti-Mines Futur) project. A consortium led by Thales Underwater Systems, BAE Systems, ECA (France) and L3Harris, Wood & Douglas and SAAB (UK) was awarded the contract in 2016 for the demonstration and assessment phase. This was successfully completed ahead of schedule and a joint manufacturing contract worth £184M was awarded in November 2020. Each navy will receive 4 sets, the first complete system being due for delivery in late 2022 for evaluation prior to achieving Initial Operating Capability.

Each set comprises 4 main elements.

• A Thales Portable Operation Center (POC) including Mission Management System and Mi-MAP software for post-mission analysis. Up to 3 systems deployed at sea can be controlled from the POC simultaneously. Control is exercised at all times via a secure Man In The Loop (MITL) communications channel.
• Two Thales / L3Harris 12-metre USVs.
• The USV will deploy a Towed Synthetic Aperture Multiviews (T-SAM) vehicle carrying a Synthetic Aperture & Mine Detection Imaging Sonar (SAMDIS), to detect, classify and locate mines. SAMDIS has a low-power requirement and its performance is theoretically equal or better than the much larger sonars used by the Sandown and Hunt class MCMVs, and provides Automatic Target Recognition (ATR).
• The Multi-Shot Mine Neutralisation System (MuMNS), is used to visually locate and dispose of mines. It can be armed with up to 3 disposal munitions, This is an improvement on the single-shot Sea Fox ROV system currently in service with the RN (can be enhanced with a COBRA head for two shots).

Advantages of autonmomy

The bold move to embrace MAS implies many risks and there is a wide range of issues that will have to be addressed. However, pioneering this approach clearly has some attractions.

Safety. The most important reason is to fulfil the long-desired aspiration to remove the man from the minefield. Using robots to dispose of mines, reduces the risk to human life, a MCMV and its crew no longer has to enter a potential minefield. It also removes the need for a ship to conduct a slow and painstaking activity in an area that may also be under threat from air, missile or surface attack.

Cost. This is undoubtedly another big factor in the decision process. Requiring a much smaller number of people and removing the need to replace very expensive minehunters is a big attraction for a navy trying to balance limited resources. The Sandown class with their specialised low-signature equipment fit are said to be the most expensive vessels ever built for the RN when calculated by cost per tonne. A very crude estimate would be that replacing the RN’s 13 minehunters with modern equivalents would cost at least £1Bn. The MMCM sets cost around £20M each, and the unit cost may fall if further with further UK, French and export orders. Even allowing for the investment in development, the capital costs of the autonomous systems are probably around 30% of crewed alternatives and through-life costs are even lower. Potentially the RN could choose to invest in many sets, including specialist RTSV, CIS and MMCM allowing much greater coverage than the 13 ships could ever provide.

Agility. The mine threat is rapidly evolving as they become smarter and able to distinguish between targets, resist countermeasures and even relocate themselves depending on pre-set conditions. The USV payloads and software can be adapted and evolved quickly to meet new threats. Displacing very little, the USV is inherently more stealthy than a manned MCMV. The RN claims its new uncrewed MCM systems have already proven to be dramatically faster in operation and can find mines, even in the worst conditions, “five to 10 times faster than current ships”.

Portability. The new autonomous MCM systems are small enough to be either air-portable or fit into the adaptable mission bay of the Type 26 (and probably eventually the Type 32) frigates. This offers a major tactical and even strategic advantage. Future RN task groups can include their own organic MCM capability that could be launched and controlled from a frigate or other platform. If there is a known potential mine threat, instead of either taking a big risk pressing on or waiting weeks for an MCMV to arrive, USVs can be sent ahead of the force and hunt and clear mines right away. Provided there is a friendly airfield and port available, the systems can also be flown out to anywhere in the world to rapidly deal with an emerging mine threat.

A new set of challenges

while the assessment and demonstration phases have provided great confidence that MAS can perform the basic mine detection, classification and destruction functions, there are accompanying drawbacks. Some of the issues are universally applicable to uncrewed and remotely piloted systems of all types and some are specific to mine warfare.

Lack of presence. An MCMV with its ship’s company provides visible presence and in addition to its core mine warfare tasking, may also be used for patrol duties. Without air or surface assets in close support, which rather negates many of its advantages, the USV is much more vulnerable than a crewed vessel. While many conflicts remain in the threshold below open warfare it would be attractive and relatively easy for adversaries to destroy or simply steal the USVs. There have already been examples of drones being destroyed without dramatically escalating conflicts in the way that attacking an inhabited vehicle would imply. The USV simply lacks the perceived importance and the self-protection capability of an MCMV.

Reliability. Any vessel that puts to sea operates in a hostile environment and is prone to breakdown. However well engineered, inevitably some aspect of the USV may malfunction on occasions. Something that might be relatively simple for a sailor on the spot to repair will render the system useless and may even impede its return to base. The LARS on the back of the USV will have to be exceptionally reliable –  the sonar bodies and ROV must be streamed and recovered without mishap every time. Although the remote operator is fed back images to help with decision making, there may be occasions when the ROV is no substitute for the experience, instincts and dexterity of a naval diver.

The global requirement for MCM implies the USV itself and its mechanical systems must withstand snow and ice, high winds, extreme heat and even sandstorms. Foul weather may temporarily impede or stop an MCMV from its work but it can remain in theatre and ride out the storm. To avoid being completely lost or damaged beyond repair, the USV must return to base or its mothership in the event of bad weather

Jamming. To exercise control of the USV and retain a man in the decision-making loop, requires unhindered access to the electromagnetic spectrum which may not always be available. Theoretically, an MCM USV in the Gulf or Baltic could be controlled via satellite data link from the UK. More commonly control will be exercised by radio data links from a ship or somewhere ashore, closer to the area of operations. Adversaries are working hard to deny these communication channels via jamming and potentially destroying satellites as well as attempting cyber intrusions. In the event that contact is lost, the USV has sufficient autonomous decision making capability to return to base but its mission would likely be aborted. Improvements in AI may offer the opportunity to field entirely independent systems in future but there is great reluctance to ‘go kenetic’ without human control, including placing explosives on suspected mines.

Keeping mum

Unlike its European counterparts, the RN has no published plan at present to provide motherships for its mine warfare MAS. The assumption is that they will either operate from bases ashore, be carried by frigates or perhaps on other ‘vessels of opportunity’. There is a very strong case for obtaining two or three MCM motherships, even if a very basic merchant ship conversion or lease. A Bay-Class auxiliary will probably act as the first operational mothership next year, forward-deployed in the Gulf. The plan for two Littoral Strike groups from 2024 would suggest all three of these vessels will be needed for their core amphibious role.

It does not make sense to tie down a frigate for sustained MCM operations, although the ability to temporarily embark the capability is a great advantage. A dedicated mothership can self-deploy wherever needed, be self-supporting in-theatre for some time, close to the area of operations but at a safe range. It can embark mine warfare specialists, the containerised POC and as well as maintainers and a stock of spares. It would also restore some of the valuable naval presence that lost by deleting the MCMVs.

Capability is ultimately more important than platforms but the implications for the RN of the loss of 13 hulls will be considered in a future article.