Radar Refits: F-15s Looking for the AESA EdgeOct 02, 2012 14:00 UTC by Defense Industry Daily staff
Most F-15C Eagle air superiority fighters use APG-63 radars, passive arrays mounted on a movable swashplate. While upgrades over the years have improved them, a new generation of radar technologies has appeared. With cruise missile defense rising in importance, and longer-range detection desired, upgrades are necessary. That requires new radars, using AESA technologies that dramatically improve range, while reducing maintenance. The USAF has also discussed a retrofit set that would turn the F-15C Eagless into multi-role fighters, and a next-generation AESA radar would be part of that, too. Meanwhile, they’ve started a program to upgrade select F-15C units with AESA radars, as an air-air improvement.
Those F-15C units will now be joined by the USAF’s entire 2-seat, multi-role F-15E Strike Eagle fleet, whose future AESA radar has received some improvements, and a new designation.
The F-15′s Radars
The USAF’s F-15C air superiority fighters have traditionally used APG-63 pulse-Doppler radars, passive arrays that use a movable mounting to create their coverage area. Almost 1,000 APG-63s had been delivered when production ended in 1986, and about 700 are still operational in F-15As, Bs, and early model Cs and Ds operated by the US military and the air forces of Israel, Japan, and Saudi Arabia.
The multi-mode AN/APG-70 is a 1980s derivative of the APG-63 that adds air-ground modes and maintainability improvements. Gate array technology adds air-ground modes, and improves air-air effectiveness. The APG-70 is employed on late model F-15C/D Eagles, all F-15E Strike Eagle aircraft, and on the Israeli F-15I and Saudi F15S Strike Eagle variants. Beyond the F-15, a variant of the APG-70 radar called the AN/APQ-180 adds a modified planar array, an upgraded signal processor, and several enhanced air-to-ground modes, for use on the USA’s AC-130U Specter gunship aircraft.
The AN/APG-63v1 is a 1990s-era reliability/ maintainability upgrade that adds modern back-end hardware, and enhances air-air and air-ground capabilities. It is NOT an AESA radar, but could be refitted with an AESA front end. Raytheon has received 5 production orders to deliver 161 APG-63v1 radar systems plus spares to the US Air Force, and the first units entered service in March 2001. Up to 170 may be ordered. Another 60+ radar systems and spares will be delivered to Korea for their F-15K. Some Japanese F-15Js have been fitted with a license-produced Mitsubishi Electric (Melco) APG-63v1, as a first step toward their own general fleet upgrade.
In contrast, Active Electronically-Scanned Array (AESA) radars are made of hundreds or thousands of small transmitter/receiver (TR) elements. Moving parts are eliminated; instead, subsets of their array elements are used to focus on each task very quickly and precisely, without having to move the elements physically, and with little signal “leakage” outside of its focused beams. This makes them more reliable, more powerful, and able to operate in multiple modes at once. New radars may also correct a known air-air weakness in previous radars that can reputedly be exploited by aircraft like Russia’s SU-30 family, though other reports claim that existing radars have closed that hole.
There’s even a maintenance advantage to AESA technology. A partial failure in previous radars renders them unfit for use, but AESA radars only suffer a slight performance drop if some of their thousands of TR modules fail. The fighter can still fly, enjoying all of the radar’s simul-mode, range, focusing, low “leakage,” and communications benefits. In most cases, the fix isn’t even deemed to be worth the time.
AESA radars have taken a while to enter widespread service on fighter aircraft because the cost of each array had to come down to an affordable level, but once that happened, their advantages become compelling.
Raytheon’s AN/APG-63v2 was the world’s first AESA radar system to be operationally deployed in a fighter aircraft, entering service with the F-15Cs at Elmendorf Air Force Base, Alaska in December 2000. At present, 18 operational F-15Cs fly with the APG-63v2 radar, and a 19th F-15C has been equipped with the APG-63v3 for testing purposes. Current plans call for up to 48 more APG-63v3-equipped F-15C/Ds to join them, but some options under discussion could grow that number.
The Raytheon APG-63v3 AESA radar combines APG-63v2 AESA software with the hardware advances that went into the F/A-18 E/F Super Hornet Block II’s AN/APG-79 AESA radar. Whereas the AP-63v2 AESA had a square profile, the APG-63v3 can be recognized by the rounder shape of its array. It uses lighter and more advanced AESA technologies that include a tile array arrangement, and a new processor.
The ‘v3′ is being fitted to F-15C aircraft as an extension of earlier air-air upgrades, and a variant was picked to equip the USAF’s F-15E Radar Modernization Program (RMP), beating Northrop Grumman’s offer of the AN/APG-77v1 radar that equips the USAF’s F-22A Block 20 Raptors. On the export front, Singapore’s new F-15SG Strike Eagles and Saudi Arabia’s F-15SAs will use the APG-63v3 radar. Japan has reportedly expressed interest in it as a fleet upgrade possibility for its F-15J (F-15 C/D equivalents), and it has been offered to South Korea as part of Boeing’s F-XIII bid of its stealth-enhanced F-15SE Silent Eagle.
The F-15E RMP program’s fit-out would add a few refinements to the ‘v3,’ and receive a new designation: AN/APG-82v1. New Radio Frequency Tunable Filters (RFTF) will enable the aircraft’s radar and Electronic Warfare System to function at the same time, and an improved Environmental Cooling System (ECS) will improve liquid cooling capacity 250%. Best of all, instead of large LRU “black box” units that must be sent to a maintenance depot for diagnosis and service, the radar borrows from the Super Hornet’s APG-79 and uses advanced internal diagnostics, plus smaller LRM “blades” that can be swapped out in the field based on the diagnostic reports. A new wideband radar radome completes the major modifications.
In future, the APG-82′s commonality with the APG-79 offers another benefit: new radar capabilities can be transferred from one radar to the other via software upgrades. The USAF would still have to conduct full testing of the upgrades, but this level of commonality does save a lot of money and time.
The APG-82 is currently in the System Development and Demonstration phase, though low-rate production has begun. Flight tests began in 2010, and Boeing expects to achieve Initial Operational Capability during FY 2014.
Contracts & Key Events
FY 2011 – 2012
APG-63v3. APG-82 LRIP-2. Future F-15 capabilities.
The Advanced Display/Core Processor II (ADCP II) program will replace all the computers in USAF F-15Es with modern mission computers, gigabit ethernet, and fiber channel connections. A Milestone B decision is scheduled for November 2012. ADCP II would help F-15s take more advantage of their AESA radars, especially for advanced modes like jamming.
The Advanced Cockpit System option would replace 23 existing instruments with with a 22″ display, a low-profile head-up display, a reference standby display and a low-profile engine fuel hydraulics display. Elbit is already a confirmed partner, and ACS has been submitted with the stealth-enhanced F-15SE for the Korean F-X-III fighter competition.
Finally, a proposed new Digital Electronic Warfare System (DEWS) would replace many of the planes ECM gear, providing the advantages of Digital Radio Frequency Memory signal replication and re-transmission, along with more than 200% throughput and memory growth reserve compared to existing options. DEWS has also been submitted with the stealth-enhanced F-15SE for the Korean F-X-III fighter competition. Defense Tech.
Aug 29/12: Support. Boeing announces an $85 million Performance-Based Logistics (PBL) contract for continued support of U.S. Air Force F-15 mechanically scanned and Active Electronically Scanned Array (AESA) radars. As the number of F-15 AESAs grows, a unified support framework becomes more and more important.
The new contract replaces 3 previous support contracts with one overarching agreement, and integrates a Boeing Contractor Logistics Support team into assigned Air Force wings. These people are considered active-duty civilians, and will be deployable worldwide. Boeing.
July 23/12: APG-82 LRIP-2. Boeing says that the USAF has granted the F-15E Radar Modernization Program (RMP) approval to begin Low Rate Initial Production Lot 2: 10 APG-82v1 AESA radars.
Installation of the Raytheon-built AESA radar systems is scheduled to begin in the 3rd quarter of 2013. Meanwhile, the APG-82 is undergoing an aggressive flight test program at Eglin AFB, FL, and Nellis AFB, NV. A September Raytheon release confirms the sub-contract from Boeing for those 10 radars, which will begin deliveries when LRIP-1 deliveries, in February 2014. Boeing | Raytheon.
Sept 27/11: APG-82. Boeing receives Milestone C authorization for the F-15E RMP, which authorizes Low-Rate initial Production. LRIP Lot 1 is for 6 AN/APG-82v1 systems, and will be followed by 10 radars in LRIP-2, and 17 radars in LRIP-3.
Meanwhile, the RMP is performing an aggressive 14-month, 110-sortie flight test program at Eglin AFB, FL; Nellis AFB, NV; and Holloman AFB, NM. Boeing.
F-15E RMP Milestone C
Jan 18/11: APG-82. Officials from the 46th Test Wing launch the first flight of an F-15E with the APG-82v1. A USAF release says the new radar is “expected to have approximately a 20-fold improvement in aircraft reliability,” and reported positive detection of an F-16 on this 1st flight, at greater ranges than the old APG-70 radar.
Developmental testing is scheduled to continue through 2012, but early operational testing will proceed in parallel. Officials have begun modifying a 53rd Wing F-15E with the new radar and they plan to begin some of the operational testing as early as March 2011. Installation in all F-15Es is expected to begin around 2014. USAF.
APG-82 1st flight
Dec 7/10: APG-63v3 order. Raytheon announces a contract from Boeing for AN/APG-63v3 AESA radars, to equip F-15Cs of the U.S. Air Force and U.S. Air National Guard. It’s a private contract, so numbers were not disclosed. Deliveries will begin in the 2nd quarter of 2011. Raytheon release.
Oct 21/10: APG-63v3. The 71st Fighter Squadron’s 4 upgraded F-15Cs arrive at Kadena Air Base, Japan, joining the APG-63v1 (non-AESA) and v2 (earlier AESA) equipped aircraft already in the 44th and 67th Fighter Squadrons.
Boeing says they are under contract to fully upgrade 27 Air Force and 18 Air National Guard F-15C/D aircraft with the APG-63v3 radar over the next 10 months. A total of 54 AESA-equipped (APG-63v2 or v3) F-15C/Ds are scheduled to be on station at Kadena AB by September 2013. Boeing. See also Sept 13/10 entry.
Sept 14/10: APG-82. Raytheon announces that they have delivered the first APG-82v1 radar for the USAF’s F-15E radar modernization program. The firm claims “more than 20 times the system reliability of previously installed APG-70 radar systems on the F-15E.”
The new radar is part of a contract to deliver APG-82 AESA radar test units and support to Boeing, who installs the radars in their F-15Es and integrates them with the weapons computers and avionics. Integration will take place at Boeing facilities in St. Louis, MO, followed by developmental and initial operational test and evaluation flight programs.
1st APG-82v1 delivered
FY 2009 – 2010
F-15C+ rollout. APG-82v1.
Sept 13/10: APG-63v3. Raytheon announces that the first APG-63v3 radar is now deemed to be officially installed on a USAF F-15C air superiority fighter, following a series of successful flight tests.
Combat Aircraft’s August 2010 issue says that the 71st Fighter Squadron at Langley, VA has had 8 of its F-15Cs equipped with the new radar. The USAF will send 4 to Kadena AB, Japan and the other 4 to Nellis AFB, NV. The Nellis AFB aircraft will be used for weapons instruction and training, and test support.
June 10/10: APG-82. Boeing receives the first APG-82v1 radar test set from Raytheon. The radar test set, which has successfully completed Acceptance Test Procedures, will undergo further tests at Boeing’s Electronic Systems Integration Lab in St. Louis, MO before being integrated into an F-15E.
Raytheon is producing 5 AESA radar test units as part of the Engineering and Manufacturing Development phase of the program, and will support Boeing’s integration of AESA into the F-15E at Boeing’s St. Louis facilities. Testing and evaluation will follow. Boeing.
April 14/10: F-15C role expands. Aviation Week reports that AESA-equipped USAF F-15Cs will be forced to shoulder about 50% of the “air dominance” burden once allocated to the F-22A:
“Each fighter type will shoulder 50% of the air dominance mission… “Our objective is to fly in front [of any strike force] with the F-22s, and have the persistence [because of larger fuel loads] to stay there while the [stealthy fighters] are conducting their LO attack,” says Maj. Todd Giggy, the wing’s chief of weapons and tactics… The Florida, Louisiana and Oregon ANG will field the first 48 V3 radar-equipped F-15Cs. Massachusetts and Montana ANG units will follow so that the East, West and Gulf coasts have a cruise missile defense capability.”
April 12/10: Boeing, the USAF, and Florida’s Air National Guard (ANG) roll out the first operational ANG F-15C equipped with an AN/APG-63v3 AESA radar, under a contract to upgrade 14 ANG and 10 USAF F-15C/Ds. Boeing release.
March 31/10: Sub-contractors. A new radar also needs a new radome nose cone. General Dynamics Armament and Technical Products announces that it has delivered its first F-15 wideband nose radome to The Boeing Company in support of the F-15 Radar Modernization Program (RMP). Delivery of the AN/APG-82v1′s companion nosecone falls under a system development and demonstration (SDD) contract that was formally awarded in October 2008. See also May 2/08 entry, noting GD ATP’s earlier selection as the preferred partner.
Benefits of the new radome include superior electrical performance over a wide frequency range, low weight, low part count, and the ability to perform in high heat and stress environment. The radome also includes the installation and integration of an instrument landing system antenna.
Nov 6/09: Sub-contractors. Giga-tronics Inc.’s Microsource subsidiary announces that its new Radio Frequency Tunable Filters (RFTF) will be part of the AN/APG-82v1. RFTFs allow the radar and electronic warfare system to function at the same time, by minimizing interference. Microsource Inc. in Santa Rosa, CA developed the modified RFTF specifically for the F-15 RMP program during a 9-month collaborative process, leveraging its previous RFTF work with Boeing and Raytheon for the Super Hornet‘s AN/APG-79 AESA radar.
Oct 30/08: In November 2007, Boeing picked Raytheon’s APG-63v3 AESA radar to modernize its F-15E Strike Eagles. Now Boeing announces a $238 million System Development and Demonstration (SDD) contract from the USAF, which begins to finance that work. During the SDD phase, Raytheon will produce developmental and flight-test radar units, while Boeing ensures that the new radars work with the F-15E’s full array of electronics and systems. A sub-contract to Raytheon can be expected to follow shortly, and work on the SDD phase is expected to finish in September 2012.
Initial operational capability (IOC) for the upgraded F-5Es is expected in FY 2014, with the fielding of 12 operational aircraft. Those radars and aircraft integration work will be part of a separate low-rate initial production (LRIP) contract, not the SDD phase. Boeing release.
F-15E RMP SDD
FY 2005 – 2008
Raytheon wins with APG-63v3. Subcontractors.
May 2/08: Sub-contractors. General Dynamics Armament and Technical Products announces a sub-contract from Boeing to develop the next generation of wideband radomes for the F-15 Radar Modernization Program. The System Design & Development contract scope included radome design, material strength and environmental testing, environmental and structural qualification, tool design, fabrication, assembly, and repair-methods development.
Production and program management is being performed at General Dynamics’ advanced materials facility in Marion, VA, with 10 radomes to be built by April 2011, as part of the SDD phase. Boeing has picked a winning radar design for the program, but the formal USAF radar contract wouldn’t be signed until October 2008, with 1st delivery of a radome to Boeing taking place in March 2010.
March 17/08: APG-63v3 order. Boeing announces a $130 million U.S. Air Force contract to upgrade 16 Air Force and Air National Guard F-15C Eagles with the APG-63v3 AESA radar, bringing the total to 24. Raytheon adds that its contracts with Boeing are worth just in excess of $89.5 million, and authorize production of 8 APG-63v3 AESA radar systems for the US Air National Guard plus 8 systems for the Air Force.
See also the Oct 9/07 entry, which describes the delivery of 8 radars under an earlier order. Like the previous September 2007 contract, this order includes initial spares and aircraft support. Boeing release | Raytheon release.
The AESA upgrade program continues, despite concerns that America’s F-15A-D fleet appears to have have more fatigue issues, and possibly less service life, than previously thought. Careful selection of airframes to upgrade may help to mitigate this risk, which the F-15E fleet does not appear to share.
Nov 2/07: The competition between Raytheon (APG-63v3) and Northrop Grumman (the Raptor’s APG-77) to supply next-generation radars for the USAF’s F-15E Strike Eagles has a winner! Raytheon’s AN/APGv3 has been selected by Boeing to refit all 224 F-15Es in the USAF fleet, in anticipation of an Air Force F-15E RMP System Design and Development (SDD) contract in 2008. Boeing is the F-15 family’s developer and prime contractor; their deep knowledge of the platform means that they are unlikely to lose the resulting contract, even if it’s competed.
The F-15E development program will run parallel with the United States Air Force and Air National Guard F-15C AESA program, which is already in progress. During the SDD phase, Raytheon will produce AESA radar test units and support Boeing’s efforts to integrate the AESA radar into the F-15E weapon system. The integration activity will take place at Boeing facilities in St. Louis prior to entering the developmental and initial operational test and evaluation flight programs. The contract includes production options for retrofit of the fleet, once testing is complete.
Dr. Tom Kennedy, vice president for the Tactical Airborne Systems group of Raytheon SAS, adds that “Additionally, we have built in capabilities for future enhancements such as radar common data link.” RCDL is the name for the high-bandwidth AESA radar communications link DID has covered elsewhere. Boeing release | Raytheon release | Aviation Week’s Ares.
APG-63v3 picked for F-15Es
Oct 9/07: Boeing announces a $70 million contract to begin upgrading U.S. Air Force and Air National Guard F-15C Eagles with the APG-63(V)3 Active Electronically Scanned Array (AESA) radar. The upgrades will begin in first quarter 2009. Raytheon, meanwhile, describes a $52.2 million Boeing subcontract to deliver 6 APG-63v3 AESA systems and a 7th spare to the Air National Guard as part of its F-15C upgrade program. Raytheon will deliver an 8th system to the U.S. Air Force. Boeing release
| Raytheon release.
A significant part of this contract also includes production start-up costs, as well as manufacturing equipment and other spares. Raytheon expects to deliver 6 or more AN/APG-83v3 radars to the Air National Guard in coming years, for a planned total of at least 48. The new AESA radars are the latest addition to planned upgrades to some of the USA’s F-15Cs, which have included a fighter-to-fighter data link, GPS navigation, and the Joint Helmet Mounted Cueing System (JHMCS) helmet sight.
F-15C upgrade begins
Sept 27/06: APG-63v3. Raytheon announces that its APG-63v3 AESA radar for the F-15 has been delivered to the US Air Force for the final phase of developmental testing. This testing entails multiple flight tests to ensure the AESA radar system meets all performance specifications and requirements. Raytheon feature.
Aug 7/06: APG-63v3/ Raytheon announces that it has delivered the AN/APG-63v3 radar to Boeing in late June 2006, ahead of schedule, following flight tests to verify its air-air capabilities. Completion work on the antenna and final verification of the system in Raytheon’s Radar System Integration Lab, prior to flight test, were achieved in a record 7 weeks when 6-to-12 months as is usually the norm. At least 10 more flights, intended to further demonstrate enhanced air-to-air capability, are expected to begin at Eglin Air Force Base, FL in fall 2006. Raytheon release.
Sept 20/05: Competition. Flight International reports that plans to upgrade up to 150 of the USA’s multi-role F-15E Strike Eagles will feature a competition between Raytheon’s APG-63v3 radar, and the Northrop Grumman AN/APG-77 radar that equips the F-22 Raptor. As of October 2007, however, no decision has been made regarding those upgrade project. See “USAF wants competition for F-15E Strike Eagle radar upgrade.”
- Raytheon – Raytheon’s Revolutionary AESA Technology
- Raytheon – AN APG-63(V)3 AESA Radar . See also PDF brochure.
- Raytheon – AN/APG-63 (V)2 AESA Radar
- Raytheon – AN/APG-70 Radar
- Raytheon – AN/APG-63 Radar. See also AN/APG-63v1 page.
- USAF – F-15 Eagle
- GlobalSecurity – F-15 Eagle. Includes information re: US and foreign variants.
- Boeing – F-15E Strike Eagle
- Aviation Week (Aug 5/07) – Japan Chooses An Offense. Covers Japan’s requests for F-22A Raptors, and also goes into Japanese plans to upgrade its F-15Js with improved radars. Some APG-63v1s have been fitted, but Japan may be interested in converting its fleet to APG-63v3 AESAs as an interim gap-filler and a cruise missile defense supplement to the Raptors if/when they arrive.
- DefenseTech (April 20/06) – Eagles Forever. Discusses the possibility of F-15C multi-role upgrades.
- Aviation Week (April 12/06) – Moseley Considers Options For Future Force Reductions. “A roadmap of options for the remaining F-15Cs and Strike Eagles is nearly complete. That document is expected to outline needed upgrades, such as active electronically scanned array (AESA) radars, for some F-15Cs that would allow them to detect cruise missiles. Raytheon officials have been pitching upgrades to the existing radars as well as new systems for the F-15…”
- Flight International (Sept 20/05) – USAF wants competition for F-15E Strike Eagle radar upgrade
- DID (Jan 25/06) – Israel Kicks Off Program to Improve Its F-16s and F-15s. No AESA radars scheduled at this point, but they do in tend to make their F-15Cs into multi-role fighters.
- Aviation Week (March 18/04) – Roche: F/A-22”s Readiness For Key Testing Phase Is ”Iffy”. Includes a section covering the F-15C “Golden Eagle” multi-role idea.