The AN/SPS-40 is a

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

two-dimensional, long range air search

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

that is capable of providing contact bearing and range. It was replaced by the

AN/SPS-49 The AN/SPS-49 is a United States Navy two-dimensional, long range air search radar built by Raytheon that can provide contact bearing and range. It is a primary air-search radar for numerous ships in the U.S. fleet and in Spanish Navy, Spain, Poli ...

on newer ships and on ships that received the

New Threat Upgrade New Threat Upgrade (NTU) was a United States Navy program to improve and modernize the capability of existing cruisers and destroyers equipped with Terrier and Tartar anti-aircraft systems, keeping them in service longer. The Program was sele ...

. The SPS-40, being a vacuum tube design, was notoriously sensitive to the vibration from shipboard gunfire. A later redesign into a largely solid-state system not only improved its performance (cutting the number of cabinets by more than half) also featured one of the best MTI (Moving Target Indicator) units in the fleet - a rarity in the early 1970s. In accordance with the

Joint Electronics Type Designation System The Joint Electronics Type Designation System (JETDS), which was previously known as the Joint Army-Navy Nomenclature System (AN System. JAN) and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Depa ...

(JETDS), the "''AN/SPS-40''" designation represents the 40th design of an Army-Navy

electronic device Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles. It is a subfield of physics and ...

for

surface ship Surface combatants (or surface ships or surface vessels) are a subset of naval warships which are designed for warfare on the surface of the water, with their own weapons and armed forces. They are generally ships built to fight other ships, subma ...

search radar system. The JETDS system also now is used to name all

Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an executive department of the U.S. federal government charged with coordinating and supervising the six U.S. armed services: the Army, Navy, Marines, Air Force, Space Force, ...

electronic systems.

History

The forerunner of the AN/SPS-40, the AN/SPS-31 (XN-1), was developed starting June 1956 by STAVID Engineering. This radar system was determined to be too large for use in the

Fleet Rehabilitation and Modernization The Fleet Rehabilitation and Modernization (FRAM) program of the United States Navy extended the lives of World War II-era destroyers by shifting their mission from a surface attack role to that of a submarine hunter. The FRAM program also cover ...

(FRAM) program for WWII-era destroyers undergoing modernization. The SPS-40, which used numerous off-the-shelf parts, was proposed as an alternate by

BUSHIPS The United States Navy's Bureau of Ships (BuShips) was established by Congress on 20 June 1940, by a law which consolidated the functions of the Bureau of Construction and Repair (BuC&R) and the Bureau of Engineering (BuEng). The new bureau was to ...

as a suitable radar design for the FRAM program. The CNO directed procurement, in advance of service approval, on 10 March 1959 to meet the schedule for the FRAM program and provide the radar frequency diversity required by OPNAV. Development and production were conducted simultaneously. A separate Technical Evaluation, normally conducted in the contractor's plant, was not performed due to the compressed development schedule. Instead, BUSHIPS requested CNO approval for a concurrent Technical and Operational Evaluation. The equipment was installed in the in August 1961, and the evaluation was conducted by COMOPTEVFOR between September and November, 1961. After some deficiencies were corrected, the SPS-40 was accepted for service use in May 1962. An improved version, AN/SPS-40A, was introduced 1968. Produced by

Sperry Corporation Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the 20th century. Sperry ceased to exist in 1986 following a prolonged hostile takeover bid engineered by Burroughs ...

, the SPS-40A introduced a broad-band transmitter and some solid-state receiver changes. The AN/SPS-40B radar set was developed as part of the DART program to improve reliability compared to earlier versions of the SPS-40. It was installed on the s, as well as the s and the

Tarawa-class amphibious assault ship The ''Tarawa'' class is a ship class of Landing Helicopter Assault (LHA) type amphibious assault ships operated by the United States Navy (USN). Five ships were built by Ingalls Shipbuilding between 1971 and 1980; another four ships were planne ...

. The SPS-40 and SPS-40A were also upgraded to SPS-40B standard, creating the SPS-40C (from SPS-40) and SPS-40D (from SPS-40A). It also incorporated the new AIMS IFF for air control of friendly aircraft, and a Low Flier Detection Mode (LFDM). Field change 8 for the SPS-40B/C/D versions introduces a Digital Moving Target Indicator (DMTI), which automatically eliminates unwanted clutter, selecting only objects with some minimal radial velocity as targets. This improves the ability for the SPS-40 to detect targets flying over land and small targets in a strong clutter environment. The AN/SPS-40E replaces the tube-type power amplifier found on earlier versions with a solid-state transmitter and an improved cooling system.

Variants

* AN/SPS-40 - Baseline version. * AN/SPS-40A - Upgraded SPS-40, introduced 1968. * AN/SPS-40B - DART program, major reliability improvements, AIMS IFF, and LFDM. * AN/SPS-40C - SPS-40 upgraded to SPS-40B standard * AN/SPS-40D - SPS-40A upgraded to SPS-40B standard * AN/SPS-40E - SSTX upgrade, replaces vacuum tube amplifier with solid state transmitter and adds new built-in test capabilities.

On board ships

United States

* * * * * * * * * * *

Australia

Germany

Gallery

File:USS Raleigh (LPD-1) SPS-40 radar.jpg, AN/SPS-40 antenna on File:USS Raleigh (LPD-1) SPS-40 radar 2.jpg, Another view of the same antenna on ''Raleigh''

Notes

References

{{reflist

External links

GlobalSecurity AN/SPS-40

- via Tpub Sea radars Military radars of the United States Military electronics of the United States