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SRS-1 Combat DF
Combat Direction Finding

Photo of a SRS-1 Combat DF System

Description: AN/SRS-1 Combat DF Block 0 is a signal acquisition and direction-finding system providing warship commanders with near-real-time indications and warning, situational awareness, and cueing information for targeting. Combat DF greatly improves on existing signals intelligence technology by providing greater flexibility against a wider range of threat signals and increased reliability at lower cost through use of COTS workstations. The Block 1 (AN/SRS-1A) system incorporates the Automated Digital Acquisition Subsystem (ADAS) upgrade enabling exploitation of unconventional and low-probability-of-intercept (LPI) signals.

Program Status: Block 1 is now in Full-Rate Production and is being installed during new-ship construction on Wasp (LHD-1) and Flight II and Flight IIA (DDG 72-95)-class ships. Block 0 systems are also being upgraded with ADAS as back-fits on in-service LHD-1s and DDG-51s originally outfitted with SRS-1. The Block 1 system will eventually outfit seven LHDs, 24 DDG-51 Flight IIs, and four shore sites. Beginning in Fiscal Year 2000, Combat DF has been superseded by the Cooperative Outboard Baseline Logistics Update (COBLU ) Phase 1 system during construction of DDG-96 and follow-on Aegis destroyers and on LHD-8 (if fully funded and built).

Developer/Manufacturer: Sanders, Nashua, New Hampshire.

SSQ-120(V) T-RDF
Transportable-Radio Direction Finder

Description: The SSQ-120(V) Transportable-Radio Direction Finder (T-RDF) provides a low-cost Medium/High/Very High/Ultra High Frequency (MF/HF/VHF/UHF) Direction Finding (DF) capability to selected U.S. Navy ships. The receiving and processing equipment is located in a single below-decks equipment rack located in the Ship Signals Exploitation System (SSES) space. A ship receives a permanent "pre-groom" which consists of antennas, cables, and equipment rack. When needed, an equipment suite is carried onboard and installed in the equipment rack. The system can be operated independently in a "stand-alone" mode, or it can be remotely operated via software resident on a SSEE or ACCES system.

Program Status: At the end of Fiscal Year 2001, 19 T-RDF equipment suites have been fielded for use in both Atlantic and Pacific Fleets.

Developer/Manufacturer: Southwest Research Institute, San Antonio, Texas.

Anti-Submarine Warfare Combat System

Photo of the DDG 51 on Operations

Description: The SQQ-89 ASW combat system suite provides Oliver Hazard Perry (FFG-7), Spruance (DD-963), Ticonderoga (CG-47), and Arleigh Burke (DDG-51) surface warships with an integrated undersea warfare detection, classification, display, and targeting capability. The system combines and processes all sonar information, and processes and displays all SH-60B Light Airborne Multi-Purpose System (LAMPS) Mk III sensor data.

Photo of a Russian Submarine

The current system is comprised of the following subsystems:
The analog receivers of the SQS-53A/B hull-mounted sonars are being upgraded to digital by the use of COTS processors, and are redesignated SQS-53D. Planned improvements to the SQQ-89(V) include:

Program Status: New system acquisitions are for DDG-51 new-construction. Required modernization of existing systems for the shallow-water littoral warfare environment is being accomplished by the use of COTS processors and displays. Starting in FY 2003, SQQ-89(V)15+MFTA systems, designated SQQ-89A(V)15, will be procured for back-fit installations in DDG-51 warships.

Developer/Manufacturer: Lockheed Martin, Syracuse, New York.

Thermal Imaging Sensor System

Description: The Thermal Imaging Sensor System will provide surface ships with a day/night, high-resolution, infrared (IR) and visual imaging, and laser range-finder capability to augment existing optical and radar sensors, especially against small boats and floating mines. Twenty-five TISS units will be procured in an NDI program. Originally intended to be used in a rotating pool, and transferred from ship to ship in operational theaters because of funding constraints, permanent installations are now being performed. The program was expanded to include permanent installation of designated new-construction ships.

Program Status: The program received Milestone II approval and contract award in October 1995. A single test unit was procured for test and evaluation in FY 1996. The Milestone III production decision was approved in December 1996 for five LRIP units. IOC was achieved in FY 1998. A total of 25 units are under contract to support installations in five destroyers and 17 frigates expected to be deployed with the Navy's Fifth Fleet operating forces as well as two Wasp-class LHDs and one landing ship dock (LSD). It is also planned as part of the core in Cruiser Conversion.

Developer/Manufacturer: DRS Technologies, Anaheim, California.

Twin-Line Array Surveillance
Towed Array Sensor System

A stern view of USNS Able (T-AGOS 2A) showing the SURTASS handling system

Description: The SURTASS capability consists of a mobile fleet of nine ships that employ the Fleet's most capable deep and shallow-water (littoral zone) passive-acoustic towed-array sonar systems. These ships provide passive detection of quiet nuclear and diesel submarines and real-time reporting of surveillance information to theater commanders and operational units. SURTASS employs either a long-line passive-sonar acoustic array or a shorter twin-line passive-sonar acoustic array. The twin-line system is the best operational shallow-water towed array and the only multi-line towed array in the Navy. It consists of a pair of arrays towed side-by-side from a SURTASS ship and offers significant advantages for undersea surveillance operations in the littoral zone. It can be towed in water as shallow as 180 feet, provides significant directional noise rejection, offers bearing ambiguity solution without turning, allows the ship to tow at higher speed, and results in a shorter time to stabilize the array after a turn.

Program Status: The twin-line Engineering Development Model is currently installed on the USNS Assertive (T-AGOS-9), and the first production model has been installed on the USNS Bold (T-AGOS-12). Although balanced within available resources, a common twin-line configuration for all nine SURTASS ships will not be achieved until FY 2006.

Developer/Manufacturer: Johns Hopkins University/APL, Laurel, Maryland; IUSS Operations Support Center, Norfolk, Virginia; Raytheon, Long Beach, California; Digital System Resources, Fullerton, California; and Raytheon, Portsmouth, Rhode Island.

Surveillance Towed Array Sensor
System/Low Frequency Active

Description: The LFA system, the active adjunct to the SURTASS sonar system, is capable of making long-range detections of submarine and surface ship contacts. It comprises a low frequency active sonar transmitter hung below a SURTASS ship and uses the SURTASS passive towed array as the receiver. Other Navy ships with towed arrays and with the SURTASS processing system can also process the LFA signal returns in what is known as a "bi-static" mode. As a mobile system, SURTASS/LFA can be employed as a force-protection sensor wherever the force commander directs, including in forward operating areas or in support of battle group activities. A UHF SATCOM communication system provides direct voice and data connectivity between the SURTASS/LFA ship and tactical platforms.

Only one LFA system exists, and it is installed on board the leased RV Cory Chouest. LFA will be installed on USNS Impeccable (T-AGOS-23, see the separate program summary) when it becomes operational. Development continues for future LFA-type active systems employing smaller, lighter sources in support of development of a rapidly deployable LFA source.

Program Status: Following an extensive scientific research program, a Draft Overseas Environmental Impact Statement/ Environmental Impact Statement (DOEIS/EIS) has been prepared in accordance with the requirements of Presidential Executive Order (EO) 12114 (Environmental Effects Abroad of Major Federal Actions) and the National Environmental Policy Act of 1969 (NEPA). A Notice of Availability appeared in the Federal Register on 30 July 1999, announcing an extended 90-day public comment period (NEPA requires a 45-day period). Six public meetings were held in August-October 1999, in Washington D.C., Boston, Miami, Seattle, Los Angeles, and Honolulu, and three Public Hearings (in Norfolk, San Diego, and Honolulu) were conducted in October 1999. Concurrently, the Navy submitted an application to the National Marine Fisheries Service (NMFS) for a Letter of Authorization for the employment of SURTASS/LFA Sonar to meet National Security needs, as outlined above. NMFS is a Cooperating Agency with the Navy for the DOEIS/EIS, and close coordination has been maintained throughout development of the NEPA documentation.

Developer/Manufacturer: Raytheon Systems, Portsmouth, Rhode Island; Lockheed Sanders, Manchester, New Hampshire; and Alpha Marine, Galliano, Louisiana.

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