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AN/SPY-1 Radar

The heart of the AEGIS systems is an advanced, automatic detect and track, multifunctional phased-array radar, the AN/SPY-1. This high-powered (4 MW) radar is able to perform search, track and missile guidance functions simultaneously with a capability of over 100 targets. The AN/SPY-l radar system is the primary air and surface radar for the Aegis Combat System installed in the Ticonderoga (CG-47) and Arleigh Burke (DDG-51)-class warships. It is a multi-function phased-array radar capable of search, automatic detection, transition to track, tracking of air and surface targets, and missile engagement support.

A conventional, mechanically-rotating radar "sees" a target when the radar beam strikes that target once during each 360 degree rotation of the antenna. A separate tracking radar is then required to engage each target. By contrast, the computer-controlled AN/SPY-1A Phased Array Radar of the AEGIS system brings these functions together within one system. The phased array can concentrate energy where it is needed. The operator can boost the range and resolution in a particular direction without blinding the ship to threats from another side. The four fixed arrays of "SPY" send out beams of electromagnetic energy in all directions simultaneously, continuously providing a search and tracking capability for hundreds of target at the same time.

The unique SPY-1 multi-function phased array radar system replaces numerous conventional independent sensors and is designed for the most challenging environments and missions, including long-range volume search, fire control-quality tracking and ballistic missile defense. SPY-1's S-band frequency range permits optimum performance in all-weather operations and the ability to perform all major radar functions while simultaneously providing proven S-band mid-course guidance for semi-active missiles, such as the Evolved Sea Sparrow Missile, SM-2 and SM-3.


  • ANSPY-1 multifunction, phased array, fire control quality radar.
  • Very rapid transition from SPY-1 silent to full radiate and full situational awareness.
  • Fast reaction, fully/semiautomatic combat systems. Initial detection to first missile movement in less than 10 sec.
  • Salvo rate of less than 2 sec per launcher (CG-52 and above with MK 41 VLS)
  • Mix of multiple SMs.
  • Max field of fire and min blockage zones
  • Must illuminate target only for a short duration prior to intercept.
  • AN/SPY-1 radar variable sensitivity feature allowing radar sensitivity to be tailored to threat RCS, environment, and tactical situation.
  • Weapons &ID doctrine capable of automatic and semiautomatic response/action.
  • Doctrine software assists w/ ID


  • The system is designed for blue water and littoral operations however AN/SPY-1 configuration must be modified to look above the terrain to avoid causing excessive false targets from land clutter. These configuration changes may increase ship susceptibility to low and fast targets.
  • Once a target is engaged and the initial salvo fired, WCS will not allow the target to be reengaged (second salvo) until a kill evaluation has been completed.
  • AN/SPY-1 antenna height is lower than the AN/SPS-49 radar system resulting in reduced radar horizon.
  • DDG-51 Class are not equipped with a AN/SPS-49 radar (no secondary air search radar)
  • Must hold an AN/SPY-1 track. Cannot engage on a remote or AN/SPS-49 track unless equipped with CEC.

The SPY-1 radar program began in the early 1970s as part of the AEGIS weapon system development and acquisition process. Three versions of the radar have been delivered.

  • The first radar of the SPY-1 series, SPY-1A, is installed in the First AEGIS Cruiser, USS TICONDEROGA (CG 47), and subsequent ships until USS PHILIPPINE SEA (CG 58). The SPY-1 multifunction phased-array radar, characterized by its distinctive, superstructure-mounted planararray antennas, is the heart of the Aegis Combat System onboard Navy guided-missile cruisers and destroyers. The SPY-1 is capable of long-range search, automatic detection, track and engagement of aircraft, cruise missiles and surface vessels.
  • As technology improved, the development program fielded a new version of SPY-1. This new radar is the SPY-1B and, with its upgrade the SPY-1B(V), was built into USS PRINCETON (CG-59) and the remaining AEGIS cruisers. CG-59 through CG-73 are equipped with the the SPY-1B.
  • USS ARLEIGH BURKE (DDG 51) class ships, AEGIS destroyers, received the SPY-1D. SPY-1D [D for Destroyer] is a variant of the SPY-1B radar system on later TICONDEROGA (CG-47) class cruisers, tailored for a destroyer-sized ship. Significant funding is being allocated by the US Navy to upgrade or modify existing SPY-1D Aegis systems aboard the US Navy's CG-47 guided missile cruisers and DDG-51 destroyers to accomplish the TBMD function to meet US Navy requirements. These upgrades to the Aegis system consist of improved or new missiles, improved and new radars, and significant modifications to the software. SPY-1D is the only radar being considered by the US Navy today for upgrade to accommodate a TBMD capability.
  • The SPY-1D(V) Littoral Warfare Radar upgrade superseded the SPY-1D in new-construction ships beginning in FY 1998, and will deploy in DDG 51 Flight IIA ships starting in approximately 2003. It is also aboard the JDS Atago class destroyers and ROKN King Sejong the Great class destroyers. The fifth version of the radar, the SPY-1D(V) features improvements in capability against low-flying targets with small radar crosssections operating in heavy clutter environments and intense electronic countermeasures. The SPY-1D(V), installed or planned for installation in DDGs 91-112, was scheduled for operational evaluation in late 2005. The Littoral Warfare Radar, improved the radar's capability against low-altitude, reduced radar cross-section targets in heavy clutter environments and in the presence of intense electronic countermeasures. The SPY-1D radar system is the multi-function, phased-array, three-dimensional (range, altitude, and bearing) radar which conducts search, automatic detection, and tracking of air and surface targets. The SPY-1D also provides mid-course guidance for the SM-2 missile, and has also demonstrated a capability to track theater ballistic missiles. The AN/SPY-1D(V) for installation in some Flight IIA ships, is an improved system with additional moving target indicator (MTI) waveforms, and greater ability to counter deceptive Electronic Attack measures.
  • The SPY-1F [F for Frigate] maintains the power and advanced capabilities of the AEGIS system found on guided-missile cruisers and destroyers, but its size has been scaled back to fit on smaller ships. SPY-1F is a smaller, lighter version of the SPY-1D radar system, providing robust performance with Evolved Sea Sparrow Missile (ESSM) and SM-2 missile capability on frigate and corvette-sized ships. Spain's F-100 program was the first application of the SPY-1F AEGIS system for frigates, which are smaller than the large guided-missile cruisers and destroyers that were previusly the only vessels with AEGIS systems. It is also nstalled on the RNoN Fridtjof Nansen class frigates. By virtue of its size, SPY-1D is a more powerful radar and, consequently, has increased range, but both the SPY-1D and the SPY1-F have air defense and ship self-defense capabilities. The SPY-1F, on the other hand, has not been designed to provide TBMD capability through software and hardware modifications.
  • The SPY-1E upgrade in selected ships has been optimized to detect, track and engage theater ballistic missiles and is incorporated in national ballistic-missile defense nets.
  • AN/SPY-1K - Smallest version of the radar offered, intended to fit corvette-sized vessels. None currently in service. The requirement of the Israeli navy is to mount a fixed four-face phased-array radar, which can be either indigenous EL/M-2248 MF-STAR or American SPY-1K, and Mk41 VLS on their new surface combatants. Ingalls once proposed a 4,200-ton design with SPY-1K and a 16-cell Mk41 VLS buried in the superstructure while AFCON, a consortium of Bath Iron Works, IZAR, and Lockheed Martin, marketed a 2,600-ton corvette with SPY-1K and a 4-cell Mk41 VLS installed in the forward hull.

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Page last modified: 07-07-2011 12:56:27 ZULU