in electronics miniaturization, significant increases in microprocessor computation rates, and sophisticated processing algorithms have overcome the shortcomings of the previous ATT program, which was cancelled in 1994. A capability to launch multiple ATTs simultaneously to defeat multiple, salvo-fired torpedoes is a required feature. Tests of the ATT have been planned for late 2006.
Knowledge that a threat is imminent – and a kill mechanism to defeat that threat – are necessary, but clearly are not sufficient to solve the torpedo problem. For this reason, the Naval Sea Systems Command, the Program Executive Office (PEO) for Submarines, and the Office of Naval Research (ONR) have teamed on the AN/WSQ-11 Surface Ship Torpedo Defense System (TDS), which will have some application to submarines as well as to surface platforms. One aspect of ONR’s ATT project in the fleet/Force Protection Future Naval Capability program, the WSQ-11 will provide a major upgrade to current TDS capabilities in automated torpedo detection, classification, and localization sub-systems that will deliver enhanced early alertment as well as fire-control quality data for the ATT.
The Counter-Torpedo Detection/
Classification/Localization (DCL) system will provide a technical design package and advanced design models for a high-frequency array. It will also provide torpedo detection and tracking algorithms for salvo engagements of up to four threat torpedoes simultaneously. The initial focus is to equip ASW units (e.g., destroyers and cruisers), although future variants could be incorporated into ASW high value unit platforms (aircraft carriers, amphibious assault ships, etc.). The primary elements of the WSQ-11 are:
• Tripwire DCL, which includes, (1) a Flexible Towed Source (FTS) that retains SLQ-25A Nixie Acoustic Decoy Function for softkill, but adds an active acoustic source for torpedo detection, advanced processing to deal with a quiet threat, and false-alarm reduction enhancements; (2) an Acoustic Intercept Receiver that detects active acoustic signals from threat torpedoes and radiated noise from torpedo propulsion, and a receiver for FTS active returns; and (3) a Command and Control Processor, to conduct active / passive search and provide an automated threat-level response
• The hard-kill Anti-Torpedo Torpedo for all threats, a self-contained launcher, and a canisterized launch system
• SLQ-25A soft-kill upgrades to augment the Target Detection System and an improved littoral tow for deployment in shallower operating environments.
Demonstrating the Promise
In late March/early April 2006, the Navy showed the art of the possible in advanced DCL capabilities. With the USS Cleveland (LPD-7) serving as test platform, the Navy and a team headed by Ultra Electronics Ocean Systems (a U.S. subsidiary of the British firm, Ultra Electronics, which cooperatively develops torpedo defense systems for the U.S. Navy and the Royal Navy) demonstrated capabilities far in excess of what was expected at this stage in the system’s development.
“They were asked to look at salvos of up to two torpedoes,” Capt. Mark Bock, then-program manager for Undersea Defensive Warfare Systems in PEO Submarines, commented in a published interview after the tests were completed. However, instead of showing a capability against just two simultaneous torpedoes in salvo, using passive and active sources the Ultra Torpedo Recognition by Active and Passive Reconnaissance (TRAPR) DCL detected, tracked, alerted, and discriminated numerous torpedoes (as many as five launched simultaneously) in six salvoes that approached Cleveland at various geometries and speeds. At streaming speeds approaching 20 knots, the system detected the threat torpedoes – both electric and thermal-propulsion weapons – at ranges far in excess of what had been previously possible. And it did so with significantly few false alarms – on the order of one in 19 hours in passive mode and 15 false alarms (seven of which occurred together at the same time during a ship-turn into shallow water) in nine hours in active mode.
The Ultra Electronics DCL demonstration team brought a production-ready wet-end reeled onto an “E” winch, which is used in the U.K. Surface-Ship Torpedo Defense (SSTD) production system. The “E” winch was specifically designed to handle green water (it is submersible) and fits inside the footprint of the Nixie winch on most U.S. surface ships. The tri-band receive array and the active acoustic sources (flexible towed countermeasure and flexible towed source) were separated by a 300-foot extension cable, and the main tow cable installed was 2,000 feet long. The system was deployed in less than 20 minutes at 20 knots (near maximum speed for Cleveland). Inboard the processing and power supplies (power amplifiers for the active tows are integrated into the towed systems) were housed in a portable trials lab for ease of installation and removal. The system allowed for real-time processing of both active and passive DCL and system performance analysis on board, which ensured that Navy observers saw everything and nothing was left to the “magic” of post-processing. The intelligent decision manager embedded in the command and control subsystem drove engineering displays located in the portable trials lab, in Cleveland’s combat information center and flag plot. This allowed the ship’s crew to monitor the system from their normal underway duty stations. The system as deployed not only performed the required DCL functions but had fully integrated the capability to perform all of the SLQ-25A Nixie functions as well.
In sum, the Ultra DCL-1 demonstrated active and passive detection and tracking, easy installation compatibility with existing surface ship towed systems (and the notional possibility for integration of DCL technology into submarine applications, as well), torpedo detection and alerting at tactically significant ranges, minimum false alarms, and highly accurate ATT targeting.
“It was a resounding success,” Bock stated. (In May 2006, Bock became program manager of the
Ohio-class SSGN conversion program.)
The Way Ahead
The torpedo threat to U.S. and coalition naval forces is real and is growing. Tens of thousands of torpedoes – from relatively unsophisticated yet still-deadly weapons to highly complex, leading-edge designs – are in the inventories of navies worldwide. While capable of being launched from surface ships and aircraft, the submarine-launched torpedo poses the gravest danger to mission success. The “detection advantage,” i.e. “stealth,” enjoyed by the submarine over the surface ship is probably greater today than in 1948. Hence, programs like the DCL are intended to level the playing field.
Vice Admiral Metcalf understood the challenge, even if he did suggest an out-of-the-box solution. Effective torpedo defense: don’t leave homeport without it.
Mr. Howard is the Executive Program Manager for AN/WSQ-11 and Vice President of Business Development for Ultra Electronics Ocean Systems Inc. Dr. Truver directs the Center for Security Strategies and Operations in General Dynamics’ Information Technology group.
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