AN/SPQ-9B Radar Set

Last updated: 15 Nov 2021

Point of Contact
Naval Sea Systems Command
Office of Corporate Communication

Washington, D.C. 20376

(202) 781-4123

Description
The AN/SPQ-9B is an X-Band, pulse Doppler, frequency agile radar which was designed specifically for the littoral environment. It has a very high clutter improvement factor supporting a very low false track rate in the littorals and in high clutter environments.

The AN/SPQ-9B scans out to the horizon and performs simultaneous and automatic air and surface target detection and tracking of low flying Anti-Ship Cruise Missiles (ASCMs), surface threats and low/slow flying aircraft, UAVs and helicopters.

The radar consists of four air cooled below deck cabinets, a motor generator and one above deck Antenna unit. The antenna is designed, constructed and tested for low radar cross-section reflectivity (or signature) as required for stealth ship design and meets all MIL-STD-901D shock requirements. The AN/SPQ 9B radar is an unattended system. Preventative maintenance is scheduled for 3.5 hours per week.

AN/SPQ-9B training has an established Navy Enlisted Classification (1326) with a Navy-approved curriculum. The design of the radar includes built-in training aids that support both stand-alone and team training with the Combat System. The AN/SPQ-9B radar has completed all U.S. Navy qualification testing required for full-rate production. Operational evaluation (OPEVAL) was successfully completed in October 2002 onboard USS Olendorf (DD 972).

The radar is installed on CVN-68, LPD-17, CG-47, WMSL-750, LHD-1 and LHA-6 ship classes. The radar is also to be installed on DDG-51 class, DDG 39, 41, 42 (AUS), DDG AMOD, CG MOD (CG 63 and follows). CVN-68, DDG-51, LPD-17, CG-47, LHD-1, LHA-6 ship classes will receive PDD Upgrade.

Features
The radar has 90dB of clutter rejection in the air channel and 70dB of clutter rejection in the surface channel. This provides superior sub-clutter visibility.

Above decks, the radar uses a mechanically rotating, electronically stabilized antenna. The lightweight (1,500 lbs.) antenna consists of dual planar arrays mounted back-to-back, each connected to independent transmitters and receivers. The antenna and entire system passed MIL-S-901D shock as well as shipboard shock testing on USS Mesa Verde (LPD 19).

Below decks, the radar consists of three cabinets (processor, receiver/exciter and transmitter), Radar set control and motor generator. The processor cabinet performs all logical, signal processing, tracking and interface functions. The receiver/exciter generates the frequencies and clocks required by the system. The receiver/exciter also contains three receivers; two receive the radar echoes from the air and surface radio frequency (RF) received in the two arrays, and the third receives signals from the "auxiliary" antenna in the array. The auxiliary antenna is for the purpose of electronic counter-countermeasures. The output of each receiver is converted to digital baseband I-Q data for Doppler processing in the processor cabinet. The transmitter cabinet receives the RF pulses from the receiver/exciter and amplifies them for output to the antenna. The radar set control provides remote control and monitoring of radar operation in the ships Combat Information Center.

The AN/SPQ-9B radar has digital interfaces to the Aegis combat systems, the MK 34 Gun Weapon System (GWS), the MK 48 GWS and Cooperative Engagement Capability/Ship Self Defense System.

Background
The AN/SPQ-9B Anti-Ship Missile Defense (ASMD) radar program was developed under the auspices of the Program Executive Office (PEO) for Ship Defense as part of the Ship Self Defense Program in response to Chief of Naval Operations letter (serial number N865/3S6496612) dated April 2, 1993, "Requirement for ASMD Upgrade of AN/SPQ-9 Radar (U)." The improved radar initially referred to as AN/SPQ-9 (I), was developed as an Ordnance Alteration to the MK-86 Gun Fire Control System.

A previous program using the AN/APQ-164 radar was officially cancelled due to development cost growth, anticipated high production costs and doubt as to the effectiveness against very low Radar Cross-Section (RCS) targets. The remaining funding was used to develop concepts for a low cost, more conventional reflector type rotating antenna, using signal processing techniques and functional designs developed under exploratory development block programs at the Naval Research Laboratory (NRL). The Horizon Emphasis proof of concept program was defined in late 1990 and continued in 1991 as the ASMD Radar Program. In 1991, NRL Radar Division supported by the PEO Theater Air Defense developed a new AN/SPQ-9B radar concept for ASMD. The concept included an air mode that provided a new, low-cost, low RCS sea-skimmer detection capability and a surface mode with improved performance over the AN/SPQ-9A.

An Advanced Development Model radar was constructed by NRL and successfully demonstrated in land based tests in 1993-94 against ASMD representative targets, at-sea, and onboard the Self Defense Test Ship (e.g., USS DECATUR) in 1994-95. A Prime Item Development Specification was prepared and used for the solicitation of competitive bids to fabricate two (2) Production Proof Kits (PPKs) with a FY 1997 option for six (6) Low-Rate Initial Production (LRIP) units. Northrop Grumman Electronic Systems, formerly Northrop Grumman Norden Systems, was selected as the best value competitor and awarded the Cost Plus Award Fee contract 13 October 1994. Acquisition reform initiatives were incorporated into the AN/SPQ-9B ASMD program with the intent of reducing the normal development time, lowering costs and increasing the system reliability. Proof of concept success allowed the AN/SPQ-9B program to commence with LRIP at the completion of the Critical Design Review and Production Readiness Review. This plan was to reduce the delivery time to the ship by approximately 12 months. The statement of work was written so that any design corrections discovered during the remaining Engineering and Manufacturing Development of the PPKs would be incorporated into LRIP units prior to delivery.

Point of Contact
Naval Sea Systems Command
Office of Corporate Communication

Washington, D.C. 20376

(202) 781-4123

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