AN/ASQ-235 Airborne Mine Neutralization System (AMNS)

The Airborne Mine Neutralization System (AMNS) is a Navy Airborne Mine Countermeasure (AMCM) remote controlled mine neutralization system. The system has been developed for the purpose of neutralizing bottom, close-tethered, and in-volume sea mine threats by using remote controlled expendable vehicles identified as Neutralizers, launched from a MH-53E AMCM Helicopter. As of April 2007, the US Navy also planned to certify the system for use on the MH-60S helicopter. The destruction of mines is achieved by a shaped charge, which is integrated into the Neutralizer. Mission data from previous AMCM missions was used to determine approximate target position and helicopter-to target safe standoff distance. The Neutralizers on-board camera provides target identification. The system is intended for use in support of amphibious operations and clearance of port approaches.

The AMNS system is divided into three major tactical subsystems, and non-aircraft support equipment: The Operator Control Subsystem, Launch and Handling Subsystem, and the Neutralizer Subsystem. The three subsystems include an equipment configuration based on modified Non Developmental Item (NDI), Government Furnished Equipment (GFE), and newly designed components. All the AMNS equipment has the versatility for "roll-on/roll-off" use on the MH-53E helicopter.

The Operator Control Console (OCC) is a modified NDI console and is a part of the Console Assembly, which is pallet-mounted and consists of two operator seats and the OCC. The OCC receives processes, records, and displays data from and issues control commands to the Neutralizer. The OCC is used for directing both the Expendable and Training Neutralizer types to the mine target using an Acoustic Tracking System (ATS) and Neutralizer tracking data. Both Neutralizer types can be controlled from the OCC using different assigned data sets and different branch paths in the same control software. Additional functions include the pre-launch testing of the OCC including Track Point II Plus (TP II+) and Global Positioning System (GPS) interfaces. The OCC can also be used for training and mission replay. The following modifications were made to the console to support the AMNS Program:

• The Power Supply Unit was changed from 115V / 60 Hz to 115V / 400 Hz in order to fulfill MH-53E helicopter requirements.
• The console internal wiring was modified to meet the TP II+ interface and the helicopter GPS interface adaptations.
• Mounting holes were added to attach the CUT/RELEASE switch panel.
• Software was modified to, provide English text and existing US Navy ASCII symbology, provide different operations for Built-In Test (BIT), launching and guidance, and coordinate transformations from absolute to relative to the In- Water Assembly (IWA) for target and Neutralizer positions.

The Launch and Handling Subsystem (now designated AN/ASQ-232) consists of a Winch Modification Kit (WMK), IWA, Davit/Sheave Assembly (DSA), Launch Box Assembly (LBA) and IWA Cradle.

The WMK consists of an umbilical cable designed specifically for the AMNS, a slip ring assembly and a stationary Junction Box (J-Box) mounted to the AMCM Single Winch II, which is used to provide communication between the OCC, IWA, and the Neutralizers. A rotating connection is mounted inside of the winch drum in order to connect the umbilical cable to the slip ring assembly. The umbilical cable is color coded in order to provide visual cues for the port or starboard rampman to aid in determining that the Neutralizer is approximately two meters above the water just prior to release, and again when submerging the IWA to the desired depth as operations are about to commence. The stationary J-Box provides power from the helicopter platform to the cut and release mechanism located in the IWA. This J-Box mounts to the winch assembly structure and allows the slip ring to terminate to it. The Cut and Release Switch Panel is part of the WMK, but is physically mounted on the OCC. The release switch requires two conscious operator actions to cut the fiber-optic cable to the Neutralizer prior to retrieving the IWA back into the helicopter.

The IWA consolidates elements of a NDI TP II+ ATS in a single cylindrical tube housing to facilitate Neutralizer launch and tracking operations from a helicopter. The IWA also contains a fiber-optic cable cutter and Neutralizer release mechanism, which are remotely activated by the OCC operator from within the helicopter. When the Neutralizer is approximately two meters above the surface of the water, the operator commands the release mechanism to drop the Neutralizer from its position below the IWA.

When the Neutralizer has transited to a safe distance, the IWA is lowered to a depth of approximately two meters below the surface of the water. After the Neutralizer has performed its mission, the cable cutter is actuated by the operator, cutting the fiber-optic cable to the B-spool and allowing the IWA to be hoisted back into the helicopter without danger of the fiber-optic cable fouling the helicopters rotors. The IWA processing section contains the TP II+ hardware and power supply, as well as the Neutralizer release mechanisms and fiber-optic cable cutter. The in-water umbilical connection is made at the IWA processing section end cap. Once inside, the umbilical cable elements are broken out into three distinct functions: Neutralizer Fiber Optic data link, TP II+ data link, and power for cut and release.

The DSA is used for streaming of the IWA and Neutralizer and recovery of the IWA after target neutralization. The DSA interfaces with the MH-53E Helicopter structure by securing it to the litter clips provided inside the helicopter. The DSA is supported on both sides of the helicopter. The davit structure is used to mount the sheave assembly that is used to lower the IWA and Neutralizer combination into the water.

The LBA consists of a multi-function launcher system configured to allow four Neutralizers to be deployed from the MH-53E Helicopter. The LBA provides secure housing for the Neutralizers throughout the time the Neutralizers are onboard the helicopter. The LBA is located on the airframe centerline, just forward of the stub ramp. The LBA is secured to the flight deck and has vibration-isolating mounts on the bottom side to provide vibration energy absorption.

The IWA Cradle is used to hold and support the IWA during transit to the target destination. The IWA Cradle is secured to the ramp deck, using non-adjustable and adjustable tie downs.

The Neutralizer is housed in a self-propelled, remotely controlled vehicle that incorporates sensors needed to relocate and identify a mine target. The Expendable Neutralizer (a training version also exists), is a fiber-optic, cable-guided, self-propelled, mine neutralizer used to destroy bottom, close-tethered, and involume sea mine threats. The Expendable Neutralizer incorporates sensors for mine relocation and identification, propulsion and control subsystems, plus a shaped charge warhead for mine target neutralization. Mine targets are neutralized by the use of a shaped charge either by sympathetic detonation or by damaging the mine casing rendering the mine inoperative. Expendable Neutralizers are negatively buoyant and used for only one mission. Once the Expendable Neutralizer is released from the IWA, recovery of the Expendable Neutralizer is not possible due to safety reasons. The warhead arming process is irreversible. In the case of a mission where the target is not acquired or the mission is aborted, either warhead sterilization or warhead self-destruction is performed. This is dependent on which stage of the arming sequence the neutralizer is in at the time.

Expendable Neutralizer consists of the following:

• Four propulsion motor/propeller units with their own drive electronics
• One vertical thruster
• Sensors including magnetic compass, inclinometer, roll and pitch, echo sounder, and pressure gauge
• Electronics Cage
• Homing Sonar
• Power supply system consisting of a electronics box battery and four propulsion lithium battery packs
• Warhead and Safe and Arming Unit (SAU)
• Camera and Spotlight
• Transponder/Responder