Radar AN/SPY-1

Radar AN/SPY-1

The AN/SPY-1 is a United States Navy 3D radar system manufactured by Lockheed Martin. The array is a passive electronically scanned system and is a key component of the Aegis Combat System. The system is computer controlled, using four complementary antennas to provide 360 degree coverage. The system was first installed in 1973 on USS Norton Sound and entered active service in 1983 as the SPY-1A on USS Ticonderoga. The -1A was installed on ships up to CG-58, with the -1B upgrade first installed on USS Princeton in 1986. The upgraded -1B(V) was retrofitted to existing ships from CG-59 up to the last, USS Port Royal.


The first production model of SPY-1 series is SPY-1, forms the baseline configuration of all subsequent SPY-1 radars. SPY-1A has four antenna arrays in two separate deckhouses, with each antenna array containing 148 modules. Each module contains up to 32 radiating element and phase shifters, and modules are paired to form transmitting and receiving sub-arrays, which are grouped into 32 transmitting and 68 receiving arrays. Transmitting arrays are driven by eight transmitters, each with four crossed-field amplifiers (CFAs), and each CFA produces a peak power of 132 kW. There are a total of 4,096 radiators, 4,352 receivers and 128 auxiliary elements on each antenna array. The power requirement of SPY-1A is four times that of AN/SPS-48 and SPY-1 is controlled by AN/UYK-7 computer.

SPY-1A upgrade is a development of SPY-1, resulting from the deployment of SPY-1-equipped USS Ticonderoga off the Lebanese coast. It was discovered that the false alarm rate was high because the radar would pick up swarms of insects and clutter from mountainous terrain. The solution is to allow the operator to change the sensitivity profile of radar by periodically reducing attenuation, and to set threat and non threat sectors according to changing environment. The result is more efficient utilization of resources. About 10% of the software totaling thirty thousand lines had to be rewritten to accommodate the necessary upgrade. In 2003, the U.S. Navy donated a SPY-1A antenna to the National Severe Storms Laboratory in Norman, Oklahoma, making it one of the first stationary phased arrays used in weather forecasting. The Multifunction Phased Array Radar was decommissioned and removed in 2016.

SPY-1B is the model adopts VLSI resulting in increased performance and reduced size and weight. For example, the electronic cabinets area reduced from 11 to 5, with corresponding weight reduced from 14,700 lb (6,700 kg) to 10,800 lb (4,900 kg), and separate digital modules are reduced from 3,806 to 1,606. A 7-bit phase shifter replaced the 4-bit phase shifter in earlier models, with corresponding weight of phase shifters in face of the antenna reduced from 12,000 lb (5,400 kg) to 7,900 lb (3,600 kg), and a reduction of side lobe by 15 dB. There are 4,350 radiators with two side lobe cancellation antenna, each with two elements, and the radar uses eleven 16-bit microprocessors. Ability to counter steep diving missiles are improved with more energy at higher elevation or longer pulse.

SPY-1B(V) is development of earlier SPY-1B with moving target indication capability incorporated in 1997.

SPY-1D was first installed on USS Arleigh Burke in 1991, with all antenna in a single deckhouse. It is a variant of the -1B to fit the Arleigh Burke class using the UYK-43 computer, with the main antenna also used as missile uplinks, thus eliminate the need of separate missile uplink in earlier models, and the UYA-4 display in earlier models is replaced by UYQ-21 display.

SPY-1D(V), the Littoral Warfare Radar, was an upgrade introduced in 1998 with new track initiation processor for high clutter near-coast operations, where the earlier “blue water” systems were especially weak. The wave form is coded and signal processing is improved.

SPY-1E SBAR (S Band Active Array) is the only active phased array model in SPY-1 series, and it was later renamed as SPY-2, subsequently developed into VSR. SPY-1E utilizes commercial off-the-shelf (COTS) subsystems and a single faced demonstration unit was built in 2004. The weight of antenna remains the same but weight below deck is greatly reduced.

SPY-1F FARS (frigate array radar system) is a smaller version of the 1D designed to fit frigates. It is not used by the US Navy, but has been exported to Norway. The origin of the SPY-1F can be traced back to the FARS proposed to the German Navy in the 1980s. The size of the antenna of SPY-1F is reduced from the original 12 ft (4 m) with 4,350 elements to 8 feet (2.4 m) with 1,856 elements, and the range is 54% of the SPY-1D.

SPY-1F(V) is a derivative of SPY-1F with improved capability against littoral targets and cruise missiles, with better multi-mission capability.

SPY-1K is the smallest version of the radar currently offered, based on the same architecture as the 1D and 1F. It is intended for use on very small vessels such as corvettes, where the SPY-1F would be too large. The size of the antenna is further reduced to 5 ft (1.5 m) with 912 elements. As of 2007, none are in service, although the radar is incorporated into the design of the yet-unbuilt AFCON Corvette.


  • AN/SPY-1: Prototypes, USS Norton Sound.
  • AN/SPY-1A: Ticonderoga-class cruisers up to CG-58.
  • AN/SPY-1B: Ticonderoga-class cruisers starting at CG-59. 3.66 m (12-foot) diameter.
  • AN/SPY-1B(V): Upgrade for the -1B version, retrofitted to CG-59 and up.
  • AN/SPY-1D: Variant of -1B designed for Arleigh Burke-class destroyers, Japanese Kongō-class destroyers and Spanish Álvaro de Bazán-class frigates (F-101-104).
  • AN/SPY-1D(V): Littoral Warfare Radar upgrade for the -1D variant applied to DDG 51 Flight IIA, Japanese Atago-class destroyers and Maya-class destroyers, South Korean Sejong the Great-class destroyers (KDX-III), Spanish F-105 frigate and the Australian Hobart-class air warfare destroyers (AWD).
  • AN/SPY-1F: Smaller version of the -1D designed to fit frigates. Installed on the Norwegian Fridtjof Nansen-class frigates. 2.44 m (8-foot) diameter.
  • AN/SPY-1K: Smallest version of the radar offered, intended to fit corvette-sized vessels. None currently in service.


The following specifications apply to SPY-1A/B/D series.

  • Size: 12 ft (3.7 m) octagon
  • Weight above deck: 13,030 lb (5,910 kg) per face
  • Weight below deck:131,584 lb (59,685 kg)
  • Range: 175 nmi (201 mi; 324 km)
    • 45 nmi (52 mi; 83 km) against sea-skimming missiles
  • Targets simultaneously tracked: 200 each array, 800 total.
  • Band: S band
  • Pulse repetition frequency: variable
  • Scan rate (scan/min): 1 (horizon), 12 (above horizon)

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