AN/SLQ-32 Electronic Warfare (EW) systemSLQ32.jpg (22161 bytes)

The CNO first considered developing a family of inexpensive EW suites to replace and/or complement existing and planned ship surveillance sen-sors in the early 1970s. The decision was in response to the Anti-Ship Cruise Missile (ASCM) threat that became evident following Egypt’s sinking in 1967 of the Israeli destroyer ELATH using a Soviet SS-N-2 STYX. An analysis of ASCMs in development led to the conclusion that the existing AN/WLR-1 and AN/ULQ-6 systems installed on most ships could not counter ASCMs in time to prevent a hit. In addition, hard kill weapons were not effective because there was little early warning of an attack due to the characteristics of ASCMs.

In 1972, the CNO authorized development of a low-cost EW suite that resulted in the AN/SLQ-32(V). The AN/SLQ-32(V) provides operational capability for early warning of threat weapon system emitters and emitters associated with targeting platforms, threat information to own ship hard-kill weapons, automatic dispensing of chaff decoys, and Electronic Attack (EA) to alter specific and generic ASCM trajectories.

The Navy awarded the first production contract for AN/SLQ-32(V) to Raytheon in May 1977 and Initial Operational Capability (IOC) was achieved in FY 79. Operational Evaluation (OPEVAL) was conducted for the AN/SLQ-32(V)2 on the USS OLIVER HAZARD PERRY (FFG 7) in July 1979. In FY 82, the final Technical Evaluation (TECHEVAL) and OPEVAL were completed for the AN/SLQ-32(V)1 and (V)3 on board the USS MISSISSIPPI (CGN 40).

Shortly after production began, the Secretary of Defense directed the implementation of the Electronic Warfare Improvement Program (EWIP) to ensure that system performance was upgraded to meet evolving threats. The resulting improvements were implemented starting in 1987 and the system was given the nomenclature AN/SLQ-32A(V). Various Engineering Change Proposals (ECPs) were incorporated as part of the “Alpha” variant. Examples include Band 3 Improvements (ECP 206) which increased ES range by increasing the sensitivity in Band 3 and providing high elevation angle coverage; Digital Processor Unit (DPU) Upgrade (ECP 463) which incorporated a 20 MB hard drive, and provided a new processor that was three times faster than the old system; Interference Suppression (ECP 469) which improved Continuous Wave (CW) high pulse repetition frequency processing capability, increased the number of Band 3 Electromagnetic Interference (EMI) filters, increased the flexibility of the two existing fixed frequency notch filters, and reduced the processing load of the Digital Tracking Unit; and Semi-Omni Antenna for Band 3 (ECP 470) which provided increased isolation from own ship emitters by reducing the gain in the direction of the transmitters and sea reflections, and increased antenna gain in the direction of threats and improved elevation coverage. Additional improvements were made but were not part of the “Alpha” upgrade.

An integral component and an effective asset in the Navy’s Ship Self Defense System (SSDS), the AN/SLQ-32A Electronic Warfare System comprises three modular versions with increasing levels of complexity deployed in five variants:

In May 1987, the USS STARK (FFG 31) was attacked in the Persian Gulf by two Exocet missiles fired from an Iraqi Mirage fighter. After the USS STARK incident, an urgent requirement was established to provide an electronic attack capability on FFG 7s equipped with the electronic-support-only AN/SLQ-32A(V)2 Electronic Warfare (EW) system. A Rapid Development Capability project was started and in six months SIDEKICK was fielded. A rotatable pool was established to keep the operational availability high. The AN/SLQ-32A(V)2 in combination with Sidekick is known by the nomenclature AN/SLQ-32(V)5. Performance is optimized for protection of a ship from radar-directed anti-ship missiles (ASMs) and for confusion of targeting radars on hostile platforms. The AN/SLQ-32(V)5 can detect high-altitude threats and missile threats at the radar horizon, perform deception jamming of missile seekers and noise jamming of targeting radars, and track multiple emitters. The Sidekick system consists of an additional equipment rack and support equipment, which are located in the EW equipment room, and two additional outboard enclosures containing the transmitter units. The transmitter units located on the port and starboard sides each provide 180 degrees of coverage.

Unfocused noise from output traveling wave tubes is coupled into the AN/SLQ-32A(V) receivers affecting both Electronic Attack and Electronic Support functions. Topside design in certain ship classes impacts the severity of the problem. For example, SHIPALT CG 47-00268 relocated decoy launchers to avoid a RADHAZ zone but simultaneously aggravated the EMI issues. Test installation of RF Absorbent Materials (RAM) barriers between frame 174 and the AN/SLQ-32A(V)3 in USS COWPENS (CG 63) in April of 1996 resulted in Instantaneous Frequency Measurement (IFM) noise levels returning to normal. RAM barriers, like those installed in USS COWPENS, will be required on 23 non-Passive Countermeasure System (PCMS) treated CG 47 Class ships.

The Radio Frequency Isolation Self Test (RFIST) for the AN/SLQ-32(V) is approved for use and the support structure has been established. When the AN/SLQ-32(V) is performing electronic attack (EA), some of the radiated energy is reflected from the superstructure and detected by the Electronic Support (ES) receivers. The AN/SLQ-32(V) employs a process called Dynamic Threshold Leveling (DTL) that prevents radiated energy from being perceived as a new emitter, causing operator confusion and resource drain. DTL uses constants embedded in the operational software to desensitize the receiver thresholds based on the transmission’s angle and frequency to essentially eliminate false emitters caused by these reflections. RFIST was developed to replaced earlier isolation methods and systems that were manpower and equipment intensive, time-consuming, and external to the SLQ-32. RFIST utilizes the SLQ-32 receiver and transmitter systems under software control internal to the SLQ-32 itself, loaded by a separate magnetic tape cartridge (MTC) or from the hard disk in the same manner as existing SLQ-32 operational and diagnostic software.

In the past, specially trained personnel using special test equipment determined these constants. Because this process was expensive and logistically difficult to accomplish, measurements were infrequently taken or not taken at all. RFIST allows each ship’s company to perform its own measurements at a convenient time and periodicity. Because even minor changes to the area around the AN/SLQ-32(V) antenna enclosure or superstructure can change the reflecting characteristics countered by the DTL process, the RFIST process should be performed whenever changes in ship configuration occur. The more data that is available for a ship, the easier it is to recognize bad data when it occurs. Additional data also increases the confidence in the values embedded in the software. It is therefore beneficial to run RFIST as frequently as is practical. Although essential for the correct operation of the DTL process in the operational software, it is not necessary for the DTL gate width timing alignment to be properly set in order to run the RFIST program and get good results. It is essential for the AN/SLQ-32(V) to be free of faults that might affect correct operation of the system’s radio frequency part.

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