Raytheon Integrated Defense Systems, prime contractor for the AQS-22 airborne low-frequency sonar (ALFS), is working to improve dramatically the reliability and maintainability of the system with the goal of slashing the time to field system improvements from two or three years to less than six months.
The ALFS is the primary antisubmarine warfare (ASW) sensor on board the MH-60R Seahawk multi-mission helicopter, which operates from Arleigh Burke–class destroyers, Ticonderoga-class cruisers, and aircraft carriers.
Greg Black, Raytheon IDS’s director for undersea systems, said that the “context” for more effective ASW sonars is the evolving undersea threat posed by unmanned and smaller and quieter submarines, both in deep oceans and shallow coastal waters where the U.S. Navy currently deploys. Diesel-powered submarines operated by potentially hostile nations also are quieter than conventionally powered boats, requiring greater detection capability in shallow waters characterized by acoustic “clutter” caused by vessel traffic and environmental conditions.
According to Raytheon, the ALFS is a multi-frequency dipping sonar designed for detection, tracking, localization, acoustic intercept, underwater communications, and collection of environmental data. The system is capable of shifting among frequencies depending on environmental conditions.
Joe Monti, Raytheon’s ALFS program director, said the upgrade initiative is part of a company-standard continuous-improvement program, aiming both to insert advanced capabilities for the ALFS transmitter-receiver and the in-water sensor in terms of acoustic beam-forming and waveform generation—and to get those upgrades to the Fleet rapidly. In a related effort, the company is working to reduce the Navy’s total ownership cost for the system by identifying efficiencies and economies in procurement, spares, repair costs, and long-term sustainment costs.
The upgrades to ALFS and to the MH-60R acoustic-processing and display system, developed by Lockheed Martin, provide the system as much as a sevenfold increase in acoustic capability over other dipping sonars, Monti said.
Black and Monti both indicated that the sonar and processing systems are closely integrated with the Mk-54 lightweight torpedo, employed from the Burkes, Ticonderogas, and Perry-class frigates and surface combatants of many allied navies, to provide a full detect-to-engage ASW capability. The Mk-54 (see page 84, December 2012 Proceedings) evolved from a series of improvements to the widely deployed Mk-46, Mk-48, and Mk-50 lightweight torpedoes that make it highly effective in littoral environments. For shipboard operations, the Mk-54 is launched from deck-mounted Mk-32 torpedo tubes.
The integration of the ALFS and the Mk-54 allows the MH-60R to find and destroy submarines while operating independently of other platforms.
Monti pointed out that the destroyers and cruisers “get the Mk-54 capability twice,” because they can launch the torpedo from the deck tubes and from the MH-60R that operates from the ship, while carriers get it once, through the MH-60Rs equipped with ALFS and armed with the Mk-54.
Monti said the ALFS sensor, operating on board the MH-60R and integrated with the processing and display system, conducts the detection, classification, and localization of submarine targets to cue Mk-54 launch. The ALFS and the processing system provide a series of data “presets” to the Mk-54 for targeting.
Raytheon is in full-rate production for ALFS and has delivered about 60 of 150 systems on contract.
Black added that in view of the increasing submarine threat, the company anticipates extensive international interest in ALFS among navies that already have acquired the Mk-54 for surface-ship launch and see a need for a helicopter-borne ASW capability. The first sale is to the Royal Australian Navy, which last summer announced that it would acquire 24 MH-60Rs and is buying ALFS for targeting the Mk-54.