Saab has completed the first phase of a programme for a large unmanned underwater vehicle (LUUV) for the Swedish Armed Forces. Less than a year after contract award, a battery-electric demonstrator had been developed, built, launched and put through sea trials.
The Swedish Defence Materiel Administration (FMV) placed the SEK60 million (US$5.8 million) development order with Saab in August 2025. FMV leads the programme, with Saab serving as prime contractor and handling design, construction and testing. The company announced the launch on October 16, 2026, through its newly formed naval business area.
Saab has marketed the vehicle as an autonomous ocean drone (AOD). FMV likens it to a small submarine that is intended to monitor large areas autonomously. Its prospective roles include surveillance of maritime areas, protection of critical infrastructure, and detecting and deterring underwater threats.
During the first phase, the vehicle functions as a sensor platform to help operators make decisions and is not designed to carry weapons. In its baseline intelligence, surveillance and reconnaissance (ISR) configuration, the vehicle is seven metres (23 feet) long with a diameter of 1.4 metres (4.6 feet) and weighs 6.5 tonnes.
Lithium-ion batteries give the craft a range of more than 600 nautical miles at a patrol speed of about four knots. FMV's preliminary requirements called for a maximum speed of 7.6 knots and a maximum depth of 500 metres (1,600 feet).
Tunnel thrusters at the forward and aft ends provide manoeuvring and precise positioning for seabed payload delivery. Saab drew on its submarine experience in pressure-tight compartment design, signature analysis, quiet operation, and control systems.
The planned ISR fit comprises multi-aperture sidescan, intercept, forward-looking and passive flank-array sonars, together with a multibeam echosounder. A Doppler velocity log and inertial measurement unit meanwhile handle navigation.
Saab's briefing also described neural-network processing of sensor data and satellite links for passing mission information to command centres ashore or to naval and aerial platforms.
Empty space has been reserved in the LUUV and some capacity has been allocated in the weight compensation system to account for payload deployment, according to Saab Product Manager Peter Karlström.
Saab's wider AOD concept listed several seabed tasks including installing ISR systems and cables and delivering special forces equipment and power sources. Torpedo launches have been indicated as a future capability.
The vehicle is the first underwater application of Saab vessel-agnostic, open-architecture control system also used on the Swedish Royal Navy’s CB90 boats and other test platforms. The architecture has three elements: an onboard control system; a remote control centre that can operate ashore, at sea or in the air; and a fleet management system.
Operators can choose from mission, vector and direct manoeuvre modes, plus a position hold. The direct mode is primarily for recovery after loss of the main link. A configurable assault mode permits operation without a continuous link.
Saab said that the completed sea acceptance tests covered the vehicle's main functions, software and sensor integration, navigation and underwater autonomous operations, and included validation of the open-architecture control system.
The vehicle's shape and dimensions were conceived around the multi-mission portal of the Swedish Royal Navy’s A26 or Blekinge-class submarines, which Saab has described as a launch and recovery route.
Rear Admiral Fredrik Lindén, FMV's Director Naval Systems, said that the LUUV demonstrator would help identify, “what the future organic LUUV will look like for the A26 submarines.”
The next phase of the Swedish programme will concentrate on more advanced software, sensor, and autonomous capabilities. The results will inform decisions on acquisition.
| 7-metre atonomous ocean drone | |
|---|---|
| SPECIFICATIONS | |
| Type of vessel: | UUV – Surveillance and combat support |
| Designer: | Saab, Sweden |
| Builder: | Saab, Sweden |
| Length overall: | 7.0 metres (23 feet) |
| Length bp: | 1.4 metres (4.6 feet) |
| Displacement: | 6.5 tonnes |
| Cruising speed: | 4.0 knots |
| Range: | 600 nautical miles |
| Batteries: | Lithium-ion |
| Autopilot: | Saab |