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| AN/APR-39 | |
|---|---|
| Name | AN/APR-39 |
| Caption | AN/APR-39 airborne radar warning receiver |
| Origin | United States |
| Type | Radar warning receiver |
| Service | 1970s–present |
| Used by | United States Air Force, United States Navy, NATO, Saudi Arabia, Israel |
| Designer | Electronic Warfare Division |
| Manufacturer | AlliedSignal / Honeywell |
| Production date | 1970s– |
| Specifications | See Technical Specifications |
AN/APR-39 The AN/APR-39 is a family of airborne radar warning receivers (RWRs) developed for detection, identification, and threat warning of radar emissions on tactical aircraft. The system provides crews with situational awareness through audio-visual alerts and bearing information, integrating with countermeasures dispensers and cockpit displays to enable threat reaction. Fielded across multiple platforms, the system influenced electronic warfare doctrine during the Cold War and continues to be relevant in modern conflicts.
Designed in the 1970s by companies in the United States defense industry, the system emerged from operational needs identified after conflicts such as the Vietnam War and doctrinal shifts following the Yom Kippur War. Initial design teams included engineers with prior experience on programs linked to Hughes Aircraft Company, Raytheon Technologies, and the DARPA-informed projects. Requirements were shaped by organizations like the United States Air Force Electronic Warfare Center and NATO standardization offices, seeking interoperability with avionics from contractors such as General Dynamics and Lockheed Martin. Early prototypes underwent flight trials at centers like Edwards Air Force Base and test ranges associated with White Sands Missile Range.
Hardware and software architectures borrowed techniques from contemporaneous systems in programs overseen by the Electronic Systems Center and incorporated lessons from projects involving Martin Marietta and Northrop Grumman. The design emphasized modularity to allow retrofit on legacy airframes such as the F-4 Phantom II, F-15 Eagle, and A-10 Thunderbolt II while meeting electromagnetic compatibility standards set by Federal Communications Commission-influenced military specifications.
The AN/APR-39 family uses wideband RF receivers, analog-to-digital converters, and signal processing modules to detect radar emissions across VHF, UHF, and SHF bands used by surface-to-air and air-to-air radars. Core subsystems trace lineage to component suppliers that supported programs for Bell Helicopter, Sikorsky Aircraft, and Boeing, integrating with avionics buses influenced by standards such as the MIL-STD-1553 databus. Typical specifications include sector bearings accuracy sufficient for plotting on cockpit indicators and generation of discrete threat identifiers corresponding to emitters like the S-75 Dvina, SA-6 Gainful, and AN/APG-63 family.
Signal processing algorithms implement pulse detection, pulse repetition frequency analysis, and frequency-agile emitter classification, reflecting research from institutions such as Massachusetts Institute of Technology and Stanford University laboratories. Environmental and electromagnetic tolerances meet qualification criteria from testing at facilities linked to Naval Air Systems Command and Air Force Research Laboratory.
Deployed extensively from the late 1970s onward, the system saw service in theaters including deployments tied to the Gulf War, Operation Desert Storm, and various NATO operations over the Balkans. Aircraft equipped with the system participated in sorties coordinated with assets like the EA-6B Prowler, F-16 Fighting Falcon, and E-3 Sentry airborne warning and control systems. Operators included air arms of nations such as Israel, Saudi Arabia, and members of NATO where the system contributed to survivability in contested airspaces dominated by integrated air defense systems like those built from S-300 and S-200 components.
Operational feedback from squadrons attached to wings at bases like RAF Lakenheath and Aviano Air Base drove software updates and user interface refinements, while combat deployments informed tactics, techniques, and procedures promulgated by commands such as United States Central Command.
The family evolved through block upgrades and variants offering enhanced sensitivity, expanded frequency coverage, and improved human-machine interfaces. Later iterations incorporated digital signal processors and compatibility with expendable countermeasures from manufacturers related to BAE Systems and Northrop Grumman Innovation Systems. Upgrades paralleled modernization programs like the F-15E Strike Eagle avionics refresh and interoperable suites found on upgraded A-10 and legacy F-4 conversions. Retrofit kits allowed installation on rotary-wing platforms from Sikorsky and on electronic attack escorts linked to Grumman designs.
Integration used standardized mounting, connectors, and databus interfaces to fit within avionics bays of aircraft from vendors including McDonnell Douglas and Lockheed Martin. Cockpit displays and threat symbology were adapted to glass cockpit upgrades influenced by programs at Honeywell International and avionics families using standards akin to MIL-STD-1760. Integration exercises involved test pilots and systems engineers from organizations such as NASA flight research centers and military test wings operating from Nellis Air Force Base.
Field assessments credited the system with improving crew reaction times against radar-directed threats, enabling timely deployment of chaff, flares, and evasive maneuvers in engagements documented by after-action reports from operations like Desert Storm and various NATO sorties over the Former Yugoslavia. Effectiveness varied with emitter density, radar sophistication, and integration level with platforms’ defensive aids suites. Comparative analyses published within defense analysis circles referenced systems employed on platforms from Lockheed Martin and Sikorsky to benchmark performance.
The system functioned as an element within broader electronic warfare ecosystems that included electronic support, electronic attack, and electronic protection components fielded by units under commands such as Air Combat Command and Naval Air Systems Command. It interacted with suppression of enemy air defenses campaigns involving assets like the EA-18G Growler and interoperated with radar jamming pods and expendable countermeasures supplied by contractors such as Raytheon Technologies and BAE Systems. The ongoing evolution of radar technologies, including low-observable techniques promoted by Skunk Works programs, continues to drive requirements for RWR families and their successors.
Category:Radar warning receivers