A-size Autonomous Underwater Vehicles are sonobuoy-sized undersea training targets and special-mission vehicles centered on anti-submarine warfare readiness. The family includes the MK 39 EMATT and SUBMATT, with public sources describing launch from aircraft sonobuoy launchers, surface ships, range support craft, submarines, and other standard sonobuoy-launch platforms.
The A-size family is built around realistic undersea target emulation for anti-submarine warfare training. Public sources describe EMATT as an expendable target for air, surface, and subsurface ASW crews, while SUBMATT adds a submarine-launched mobile acoustic target configuration.
Lockheed Martin describes standard sonobuoy launcher compatibility across fixed-wing aircraft, helicopters, submarines, and surface vessels; the Navy fact file specifically lists ASW aircraft sonobuoy launchers, surface ships, and range support craft for MK 39 MOD 3.
The Navy says MK 39 MOD 3 generates passive tones, broadband noise, active emissions, and echo repeats for sonar and torpedo-system training.
The Navy reports more than 30,000 MK 39 EMATTs procured since the type was introduced in the 1980s, including more than 4,700 MOD 3 units since 2016.
Sources: Lockheed Martin A-Size Autonomous Underwater Vehicles; U.S. Navy MK 39 EMATT Fact File; SUBMATT product card.
Public sources use the A-size family label for small sonobuoy-sized vehicles, while MK 39 EMATT designations describe the expendable ASW training-target line and SUBMATT describes the submarine-launched mobile acoustic target.
| Variant | Configuration | Designation notes |
|---|---|---|
| MK 39 MOD 3 EMATT | Open-ocean ASW training target | The U.S. Navy fact file identifies MOD 3 as the open-ocean ASW training target in production since 2016, with acoustic and dynamic submarine-simulation outputs; Navy SBIR material lists 3-12 knot programmed speeds for the vehicle. Sources: U.S. Navy MK 39 EMATT Fact File, Navy SBIR EMATT Motor Modernization |
| MK 39 MOD 4 EMATT | Modernized MK 39 production configuration | The U.S. Navy says MOD 4 procurement began in 2022 with first delivery planned for 2024, while Saab describes its MK39 EMATT as a technology-refresh design for U.S. and partner navies. Sources: U.S. Navy MK 39 EMATT Fact File, Saab EMATT |
| SUBMATT | Submarine mobile acoustic training target | Lockheed Martin's product card describes SUBMATT as a field-programmable training target deployed from a submerged submarine through the Trash Disposal Unit or Gash Gun with a TDULK sabot. Sources: SUBMATT product card |
| SUBMATT AAT | Acoustic analysis and training configuration | Lockheed Martin describes the AAT configuration with digital signal processing, 12 run-position switches, and up to 40 acoustic, depth, or heading changes per switch. Sources: SUBMATT product card |
The family’s EMATT training target can be deployed from the P-8A sonobuoy launch system.
| Launcher | Launcher type | Launch evidence |
|---|---|---|
 | Maritime patrol aircraft | A U.S. Navy VP-5 report says EMATTs are deployable through the P-8A's sonobuoy launch system and describes a training flight that employed an EMATT. Sources: VP-5 Joins Spain in Anti-submarine Warfare Exercise |
Lockheed Martin says it has been developing and building small A-size AUVs for more than 35 years, which places the family’s origins in the early 1980s.
Sources: Lockheed Martin A-Size Autonomous Underwater Vehicles, Lockheed Martin undersea feature
Lockheed's EMATT product card, dated 2014, already described the target as a mature ASW training system and credited production of more than 12,000 EMATTs for U.S. and international navies.
Sources: EMATT product card
The U.S. Navy identifies MK 39 MOD 3 EMATT as the open-ocean ASW training target in production since 2016.
Sources: U.S. Navy MK 39 EMATT Fact File
The Navy says MOD 4 procurement began in 2022, while DoD announced a Saab contract for production, testing, delivery, and engineering services on MK 39 MOD 3 EMATT with options that could continue production through September 2032.
Sources: U.S. Navy MK 39 EMATT Fact File, DoD Saab MK 39 MOD 3 Contract Notice
Saab announced a first production order for 1,200 EMATT units from a new Cranston, Rhode Island production facility and described improvements in electronics architecture, navigation, and control.
Sources: Saab EMATT Production Order, Saab EMATT
The family page covers the best-documented A-size vehicles in public manufacturer and Navy material.
| Variant | Role | Reader note |
|---|---|---|
| MK 39 EMATT | Expendable Mobile ASW Training Target | Sonobuoy-sized acoustic target used to train ASW crews from aircraft, surface ships, and submarines; Navy reporting now distinguishes MOD 3 and MOD 4 procurement. |
| SUBMATT | Submarine Mobile Acoustic Training Target | Submarine-deployed target launched through the Trash Disposal Unit or Gash Gun with a TDULK sabot. |
| SUBMATT AAT | Acoustic analysis and training configuration | DSP-equipped configuration with 12 run-position switches and programmable acoustic, depth, and heading changes. |
Sources: U.S. Navy MK 39 EMATT Fact File; Saab EMATT; SUBMATT product card.
