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The F-22's avionics include BAE Systems E&IS radar warning receiver (RWR) AN/ALR-94,[162] AN/AAR 56 Infra-Red and Ultra-Violet MAWS (Missile Approach Warning System) and the Northrop Grumman AN/APG-77 Active Electronically Scanned Array (AESA) radar. The AN/ALR-94 is a passive receiver system to detect radar signals; composed of more than 30 antennas blended into the wings and fuselage that provide all around coverage. It was described by Tom Burbage, former F-22 program head at Lockheed Martin, as "the most technically complex piece of equipment on the aircraft." It has a greater range (250+ nmi) than the radar, allowing the F-22 to limit its own radar emissions to maximise stealth. As a target approaches, the receiver can cue the AN/APG-77 radar to track the target with a narrow beam, which can be as focused down to 2° by 2° in azimuth and elevation.[163]
The radar's information is processed by two Raytheon Common Integrated Processor (CIP)s. Each CIP can process 10.5 billion instructions per second and has 300 megabytes of memory. Information can be gathered from the radar and other onboard and offboard systems, filtered by the CIP, and offered in easy-to-digest ways on several cockpit displays, enabling the pilot to remain on top of complicated situations. The F-22's avionics software has some 1.7 million lines of code, the majority involving processing data from the radar.[166] The radar has an estimated range of 125–150 miles, though planned upgrades will allow a range of 250 miles (400 km) or more in narrow beams.[157] In 2007, tests by Northrop Grumman, Lockheed Martin, and L-3 Communications enabled the AESA system of a Raptor to act like a WiFi access point, able to transmit data at 548 megabits per second and receive at gigabit speed; this is far faster than the Link 16 system used by U.S. and allied aircraft, which transfers data at just over 1 Mbit/s.[167]
The F-22 has a threat detection and identification capability comparative with the RC-135 Rivet Joint.[157] The F-22's stealth allows it to safely operate far closer to the battlefield, compensating for the reduced capability.[157] The F-22 is capable of functioning as a "mini-AWACS", however the radar is less powerful than dedicated platforms such as the E-3 Sentry.[152] The F-22 allows its pilot to designate targets for cooperating F-15s and F-16s, and determine whether two friendly aircraft are targeting the same aircraft.[152][157] This radar system can sometimes identify targets "many times quicker than the AWACS".[157] The radar is capable of high-bandwidth data transmission; conventional radio "chatter" can be reduced via these alternative means.[157] The IEEE-1394B data bus developed for the F-22 was derived from the commercial IEEE-1394 "FireWire" bus system.[168] Sensor fusion combines data from all onboard and offboard sensors into a common view to prevent the pilot from being overwhelmed.[169]
In a critical article former Navy Secretary John Lehman wrote "[a]t least [the F-22s] are safe from cyberattack. No one in China knows how to program the '83 vintage IBM software that runs them."[170] Former Secretary of the USAF Michael Wynne blamed the use of the DoD's Ada as a reason for cost overruns and schedule slippages on many major military projects, including the F-22 Raptor.[171] The F-22 uses the INTEGRITY-178B operating system from Green Hills Software, which is also used on the F-35, several commercial airliners and the Orion Crew Exploration Vehicle.[172] However cyberattacks on Lockheed Martin's subcontractors have raised doubts about the security of the F-22's systems and its usefulness in combat as a result.[173]
Herbert J. Carlisle has said that the F-22 can datalink with the Tomahawk (missile).[17
Cockpit
The Raptor has integrated radio functionality for communicating on standard frequencies, the signal processing systems are virtualised rather than a separated hardware module.[178] Radio functions are inactive during the strictest emissions control protocols (EMCON level) to maintain stealth; at lower EMCON levels the pilot may use the radio at will.[citation needed] There has been several media reports on the F-22's inability to communicate with other aircraft and funding cuts on integrating the new datalinking standard, MADL.[179][180] Voice communication is possible, but not data transfer yet.[181] However, the Joint Tactical Radio System (JTRS), the software-defined radio project, was cancelled in October 2011 (before delivery to the F-22).[182]
The integrated control panel (ICP) is a keypad system for entering communications, navigation, and autopilot data. Two 3 in × 4 in (7.6 cm × 10 cm) up-front displays located around the ICP are used to display integrated caution advisory/warning data, communications, navigation and identification (CNI) data[183] and also serve as the stand-by flight instrumentation group and fuel quantity indicator.[184] The stand-by flight group displays an artificial horizon, for basic instrument meteorological conditions. The 8 in × 8 in (20 cm × 20 cm) primary multi-function display (PMFD) is located under the ICP, and is used for navigation and situation assessment.[184] Three 6.25 in × 6.25 in (15.9 cm × 15.9 cm) secondary multi-function displays are located around the PMFD for tactical information and stores management.[184]
The ejection seat is a version of the ACES II (Advanced Concept Ejection Seat) commonly used in USAF aircraft, with a center-mounted ejection control.[185] The F-22 has a complex life support system. Components include the on-board oxygen generation system (OBOGS), protective pilot garments, and a breathing regulator/anti-g valve controlling flow and pressure to the pilot's mask and garments. The protective garments are designed to protect against chemical/biological hazards and cold-water immersion, to counter g-forces and low pressure at high altitudes, and to provide thermal relief. It was developed under the Advanced Technology Anti-G Suit (ATAGS) project.[186] Suspicions regarding the performance of the OBOGS and life support equipment have been raised by several mishaps, including a fatal crash.[187]
The USAF initially wanted the aircraft to use direct voice input (DVI) controls. This was finally judged too technically risky and was abandoned.[188]
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