During trials off Plymouth in mid-October, BAE Systems’ autonomous RIB (Rigid Inflatable Boat) was successfully controlled from the operations room of HMS Argyll. Here we look in detail at the development of this system.
For modern navies, autonomous boats offer great potential for applications including anti-piracy operations, border control, persistent intelligence gathering, maritime security and force protection. Most importantly, they can be operated in areas of high risk without placing sailors or marines in harm’s way. The RN is already building its USV experience with specialised mine warfare boats and the small MADFOX reconnaissance boat but the autonomous RIB offers a more flexible tool to enhance or even replace some of the capabilities of standard ship’s boats carried by the surface fleet.
Work on the concept began in 2014 BAE Systems started a self-funded research and development project. Halmatic Ltd who had built the Pacific RIBs in service with the RN was purchased by BAES who worked initially with ASV Global, a small Portsmouth-based SME (subsequently bought by L3 Harris) that provided the technology for remote and autonomous boats. The uncrewed RIB was first demonstrated at the Unmanned Warrior exercise in 2016. The event was a significant first step for the RN but identified that much more work would be required around the integration of Maritime Autonomous Systems (MAS) into command and control networks as well as resolving complex safety and regulatory challenges. More specifically the RIB would need to have a useful mission payload if it was to be developed further.
BAES has employed two platforms for the development work so far; the Pacific 24 and the larger (9.5m) Pacific 950. The PAC950 is an older design used primarily by special forces and was utilised in the 2019 trials that included the first live-firing from a remotely controlled RIB. The main development work is focused on the PAC 24 as it makes sense to utilise a boat that is already in service. The technology can easily be retrofitted to existing PAC24s as required and there is long experience of operating the boat in the fleet. The exiting davits fitted to the frigates and destroyers have a maximum 3.5-tonne lifting capability which limits how the PAC24 can be equipped. In the longer term, Type 26 frigates will have a dedicated mission bay handling system (MBHS) with a capacity for larger and more sophisticated craft.
In 2019 the RN published its Naval Autonomy Strategy and awarded BAE Systems a £3.2M contract to develop the Autonomous RIB platform, this contract has subsequently been expanded and amended as the scope has increased. NavyX are responsible for the evaluation work although BAES remain the operator and will provide support and training to naval personnel.Uncrewed-RIB-Equipment-1
The trials from HMS Argyll in October achieved their objectives which were basic regulatory and safety checks as well as launch and recovery tests. Control over the boat was exercised both from temporary stations in the ship’s hangar but also integrated into the ship’s Ops Room. For this trials series, the PAC24 carried a mixed equipment fit, most notably a stabilized MSI 12.7mm gun mounting. Whether under trial or deployed operationally the gun will always be under the control of a human operator making the final decision on engagement and targeting.
Other items fitted to the boat are relatively low cost. The FLIR camera is readily available on the civilian market at around £65k – a fraction of the cost of a milspec equivalent. (The gun mount includes its own high-resolution EO cameras). The compact LRAD can be used to project voice instructions or other sounds up to 1.7km. The Acoustic Shot detection system provides ‘ears’ for the boat that can determine the direction from which shots may have been fired from and classify the weapon used. (Thales has a contract to supply 735 of the systems for the troubled Ajax armoured fighting vehicle programme so there may be a few going spare!)
Control and communication with the RIB is through a line of sight mesh radio which has a maximum useful range of around 15km. Bandwidth is similar to that of the 5G mobile phone network which is adequate for camera feed and controls but radar data has to be processed on board and simplified for transmission back to the ship. It is envisaged that in future satellite-based systems (similar to those that provide WIFI on trains) could be used for longer-range missions.
Theoretically, the P950 could operate for up to 10 days at cruising speed and cover up to 300 nautical miles in pursuit mode, reaching speeds of up to 45 knots, whilst either being remote controlled or on a semi-autonomous mission. The figures for the PAC24 are more modest, with a maximum speed of 32 knots and a range of approximately 100 nautical miles over 12 hours. The increased endurance and reach over a crewed vessel is an attractive force multiplier and a prime reason to develop autonomous RIB capability. However, there is a long way to go before this can become an operational reality. Uncrewed boats have a complex safety case which is why the majority of trials with autonomous boats conducted so far still have humans on board. Collision avoidance using AIS and Radar is relatively straightforward but the image recognition technology is not yet sufficiently mature or trusted enough to replace the human eye. Avoiding a ship or other boats is relatively simple but a child in a canoe or a floating log might be missed. This sensing capability will also eventually have to work at night or in limited visibility and needs to cope with non-cooperative adversaries in small craft that can’t be picked up on radar.
Another significant hurdle to overcome is the recovery routine. During normal boat recovery, a crewed PAC24 is steered up against the side of the ship and the lifting strop is manually attached. This can be done in up to sea state 5 by a skilled crew but it an extremely complex task for an autonomous system. BAES is now working with a specialist SME to develop a cradle for recovery.
Further work will be conducted by BAES in the coming months to prove the technology can be integrated with existing naval ship combat management systems and the RIB will participate in a live firing trial to be conducted sometime in 2022.