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AN/ALQ-99 Tactical Jamming System (TJS)

The AN/ALQ-99 Tactical Jamming System was the first fully integrated computer controlled support jamming system. The ALQ-99 was originally flown on EA-6B aircraft, which are expected to be fully retired in 2019, and is transitioning to the EA-18G, an electronic attack variant of the Navys F/A-18 fighter jet.

EA-6B and EA-18Gs can be based on aircraft carriers or in expeditionary squadrons that are deployed to land-based locations as needed. The ALQ-99/EA-6B combination was originally developed for use in major combat operations, and in 1995, the EA-6B was selected to become the sole tactical radar support jammer for all services after the Air Force decided to retire its fleet of EF-111 aircraft. The role of the EA-6B continued to expand over time. According to DOD officials, when Operation Iraqi Freedom began, EA-6Bs were used in irregular warfare environments along with another aircraft, the EC-130H Compass Call, because they provided needed jamming capabilities and there were no other airborne electronic attack assets available for this role. These and other demands have strained DODs airborne electronic attack capacity and increased the stress on systems, such as the ALQ-99. The AN/ALQ-99 intercepts and automatically processes radar signals and power manages the system's transmitters to effectively jam large numbers of diverse radar threats with very high effective radiated power (ERP). Since the deployment in the early 1970's aboard US Marine Corps and US Navy carrier-based EA-6B Prowler aircraft, the system has undergone multiple upgrades. The EA-6B/ALQ-99 combination has become an indispensable fleet asset, fully integrated into all air wing combat missions.

The AN/ALQ-99 Tactical Jamming System (TJS) onboard system includes the receiver, processor, and aircrew interfaces. The TJS also includes a selection of mission-configured jammer pods carried as external stores. Each jammer pod contains a ram air turbine generator, two selectable transmitter modules with associated antennas, and a universal exciter which is interfaced with and controlled by the onboard system and aircrew. The modular open architecture of the jammer system, which facilitates optimizing transmitters and antennas for a given frequency range, also facilitates tailored mission configurations.

The AN/ALQ-99(V) Receiver Processor Group (RPG) system was developed for use in the severe interference environment of the EA-6B jamming aircraft. The RPG had completed Operational Assessment and obtained a recommendation for production before program cancellation in 1993. Six RPG EDM systems were delivered. The AN/ALQ-99 RPG provided precision direction finding, passive ranging, identification, and threat warning, and was intended for the Navy EA-6B ADVCAP aircraft in very dense environments and in the presence of onboard jamming. This system included look-through, look-above, and look-around techniques to control the interference, as well as processing algorithms to contend with the resulting fragmented pulse data. The RPG performed surveillance, radar warning, and countermeasures management in support of standoff and escort jamming missions. The system uses four quadrants of AZ/EL interferometer arrays for full azimuth coverage precision monopulse DF measurement. The receiver is a narrowband channelizer cued receiver architecture with a wide instantaneous bandwidth and multiple cued narrowband channels for simultaneous pulse measurement capability. The RPG performed real time lookthrough control of the ALQ-99 jammers to accomplish all required threat emitter detection and measurement functions without degrading jammer effectiveness. To achieve this, data processing algorithms were developed with lookthrough samples providing as little as 1% of an emitter's pulses.

The EA-6B upgrade program included the Universal Exciter Upgrade (UEU), the Band 9/10 Transmitter (transferred to the Navy from the canceled EF-111 SIP), and the Low Band Transmitter (LBT), all of which are modular upgrades for use with the AN/ALQ-99 jamming pods. Marconi Aerospace Electrical Systems of Rockville MD delivered the first ALQ-99 Band 9/10 radar jamming transmitter for the EA-6B Prowler on 08 April 1999. This initial delivery was the first of 120 units, which will provide new jamming capabilities to counter advanced surface-to-air missile systems.

The Band 9/10 Transmitter [XMTR] was intended to be capable of replacing existing Band 9 transmitter modules in the TJS configurable architecture, while extending the transmit frequency coverage through all of the system defined Band 9 and Band 10. This design provided the extended frequency coverage with the added operational flexibility of not requiring separate Band 9 and Band 10 modules for a missionized configuration which requires transmitter coverage in both bands.

The Band 9/10 transmitter completed DT in June 1997 and the OPEVAL was conducted from July through August 1997 in accordance with the DOT&E approved Test Plan. OPEVAL test flights were conducted by VX-9 at the Electronic Combat Range at Naval Air Warfare Center, Weapons Division, China Lake, CA, at the Air Force Material Command Nellis AFB Range complex, and during other VX-9 test flights. Fleet Navy and Marine Corps Prowlers carrying the comparison baseline Band 9 XMTR configuration also supported the OPEVAL. The VX-9 operational EA-6B aircraft was configured with both of the tested Band 9/10 XMTRs.

The FY97 OPEVAL of the ACAT-III Band 9/10 XMTR was adequate to find it effective. The Band 9/10 XMTR was assessed to be only potentially suitable due to an incompatibility under some conditions between the existing extended high band radome and transmissions in the Band 10 region. The Band 9/10 XMTR met its basic requirement for equivalent effectiveness to the current Band 9 transmitter in the frequency band covered by the current Band 9 transmitter. It also demonstrated effectiveness in the Band 9 /10 extended frequency range. Some scenarios tested demonstrated a definite requirement for follow-on tactics development to ensure effective employment. The two Band 9/10 transmitters tested were the newest of five EMD systems built, and were considered to be production representative after correction of hardware deficiencies discovered during DT, and after progressive overhaul with new components during the course of the extended DT. The systems under test performed without mission affecting failures throughout the OPEVAL.

Band 10 spot dwell on some azimuths were initially limited in order to guard against possible charring or delamination of the radome material. A radome material upgrade was completed in parallel with production of the Band 9/10 transmitter modules. Due to the azimuths of concern and predominant tactics, this restriction had virtually no adverse operational impact. It was imposed to prevent inadvertent damage of the radome. The radome upgrade was fully funded and assessed as a low technical risk. The Navy's stated plan was to conduct FOT&E to demonstrate resolution of the radome incompatibility prior to any fleet deployment of the Band 9/10 XMTR, in order to field the system without operator controlled azimuth restrictions.

The Low Band Transmitter (LBT) was designed for 1-3 Band Coverage, with several types of azimuth coverages (omni, bi-directional, or sector). The LBT is designed to support communications jamming, and to be controlled via direct 1553 Bus Control. Operationally, the LBT is missionized by one of four Antenna assemblies (3 Horizontal & 1 Vertical): Horiz Low (coverage Freq Low (FL) to FL+80), Horiz Mid (FL+70 to FL+230), Horiz High (FL+205 to Freq High (FH)). The one vertical antenna can be operated in two sub-bands: Vertical Low (FL to FL+20), and Vert High (FL+15 TO FH).

For LBT antennae which can be in either an omni mode or a bi-directional mode, the design called for the Central Mission Computer (CMC) to automatically switch antenna modes to ensure that all threats are covered. Scenarios could be imagined (terrain masking, etc), where the operator might wish to select the antenna mode either in mission planning or manually. The operator should be able to specify by phase during mission planning whether he/she wants: 1) CMC auto control, 2) Bi-directional only, or 3) Omni only. Additionally, the operator should be able to interogate an assignment and change the antenna mode; mode will remain in effect until the altered assignment is cleared (either by phase if a phase PA, or by the operator if a DA, AA, or operator made PA).

The repackaged system can be configured as a Single-Seat Basic System or as a Dual-Seat Enhanced System. Contained within a pod, the electronics within the ALQ-99 utilizes a pre-mission planning system. This allows the user to achieve high-jamming capability at a low cost.

  • Single Seat Basic System The basic system would be contained in standard ALQ-99 jammer pods that provide a preemptive jamming capability against all threats in all directions. Ground-based mission planning would determine the jamming requirements and would be preloaded prior to aircraft takeoff. The system would be installed with minimal impact to the host aircraft and could be quickly converted between a support jamming platform and its primary role (fighter or strike aircraft).
  • Dual-Seat Enhanced System The enhanced system would add a receiving suite and additional processing which would provide an increased jamming capability and improved jammer management and mission effectiveness. The receiver suite maybe pod mounted or carried internally. The enhanced option also requires the expansion of the operator's displays and controls capability. An additional operator in the loop takes advantage of the added capabilities, control of the receivers, and jammers.

The Single-Seat and Dual-Seat configurations were approved for export. The pod components, Hardback, Ram Air Turbine (RAT), Transmitters, Transmit Antennas, and Radome are currently in U.S. Navy/USAF inventory. Much of the software needed for the basic system was inherent in the EA-6B or EF-111.

On 07 January 2013 the Naval Air Warfare Center Weapons Division (NAWCWD), China Lake, CA, entered into a three year Cost Plus Fixed fee (CPFF), Level-of-Effort (LOE) contract using other than full and open competition with Wyle Laboratories, Inc., 7800 Highway 20 West, Huntsville, AL 35806, for requirements analysis, design, development, integration, and testing of tactical operational flight software in support of the Airborne Electronic Attack (AEA) Integrated Product Team (IPT).

Software development includes new requirements, changes to existing requirements and correction of deficiencies identified by the fleet operators. Software development will be required for the: ALQ-99 Universal Exciter Upgrade (UEU); ALQ-99 Low Band Transmitter (LBT); ALQ-99 Band 9/10 Transmitter. As the sole designer and developer (under previous government contracts) of the ALQ-99 UEU Software Development Laboratory (SDL), Wyle is the only firm which possesses the UEU knowledge and experience required to design, develop, integrate, and test the UEU OFP software without either substantial duplication of cost or unacceptable delay to the government.

On 16 January 2014 the Naval Surface Warfare Center (NSWC), Crane Division sought information from interested parties for a potential upgrade of the AN/ALQ-99 Tactical Jamming System's Ram Air Turbo-Generator (RAT-GEN) and Generator Control Unit (GCU). This work is being conducted at the direction of the Program Executive Officer for Tactical Aircraft, EA-6B/Airborne Electronic Attack (AEA) Program Manager, PMA-234, in connection with Concept Exploration Activities for the NGJ Increment (Inc) 2 program. This RFI is focused on identifying capabilities in the market place and obtaining related technical information for preliminary design and prototype fabrication and testing for a modified ALQ-99 RAT-GEN and GCU, capable of increased power output and potentially improved reliability and maintainability (R&M).






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