The Lockheed Martin F-35 Lightning II is a single engine, single seat, supersonic multirole fighter. Classified as a fifth generation fighter it is stealth even when armed, has a Low Probability of Intercept Radar, a high performance airframe, advanced avionics and highly integrated computer systems capable of networking with external sources of target-information. The F-35 can be refuelled in-flight.
Stealth is a combination of technologies used to reduce the various signatures of an aircraft, missile or any detectable object. Stealth technology is used to interfere with radar as well as reduce visibility in the infra red, visual, audio and radio frequency spectrums. From the shape of the plane, the avionics and radar systems, the engines, the internal weapon-bays to the materials used and the coating of the aircraft, everything is designed for the aircraft to be stealth.
Mission systems and Sensor Fusion
The F-35 incorporates an extensive sensor and communications suite for situational awareness, command and control and network-centric warfare capabilities.
The F-35’s sensor fusion enables pilots to draw on information from all of their on-board sensors to create a single integrated picture of the battlefield. All of the information gathered is then automatically shared with other pilots and command and control operating centers on their network using datalinks. These secure datalinks, such as the Multifunction Advanced Data Link (MADL), will enable pilots to share data with other strike aircraft as well as other airborne, surface and ground-based platforms required to perform the assigned missions.
APG-81 AESA radar
The APG-81 Active electronically scanned array (AESA) radar is the successor to the F-22's APG-77. It's the F-35's main sensor and is used for both air-to-air and air-to-ground roles. The main advantages of the APG-81 AESA radar are its ability to form multiple radar beams simultaneously to track multiple objects in multiple radar modes, frequency hopping to lower the chance of the F-35 being detected by its active radar and the ability to jam other radars.
The APG-81 radar has a Synthetic Aperture Radar (SAR) function to create high definition maps which can then be used to automatically identify targets on it and it can use Non Cooperative Target Recognition to “Map” out aircraft to identify them or analyze their thrust signature.
The APG-81 also has a color-weather mode for navigating thunderstorms and squall lines.
The Distributed Aperture System (DAS) sends high resolution real-time imagery to the pilot’s helmet from six infrared cameras mounted around the aircraft, allowing pilots to see the environment around them – day or night - thereby forming a spherical situational awareness system.
Part of the data fusion is that the DAS is completely integrated with other sensors within the aircraft. If the F-35′s radar detects something of interest, DAS’s software will analyze it and make the pilot aware of potential threats. When there are multiple threats, the DAS is able to identify the highest value targets and recommend the order in which to deal with each threat.
The DAS provides:
* Precision tracking of wingmen/friendly aircraft for tactical maneuvering.
The F-35’s Electro-Optical Targeting System (EOTS) is a sensor that combines forward-looking infrared (FLIR), infrared search and track (IRST) and laser designation plus laser spot tracker for cooperative engagements. By combining these systems the EOTS can cover both air-to-ground and air-to-air missions:
* IRST Long range air-to-air
The EOTS is integrated into the F-35’s fuselage to enhance stealth and reduce drag and is linked to the aircraft's integrated central computer through a high-speed fiber-optic interface.
It will initially be able to share still images to troops on the ground. Later in development there will be a Common Data Link(CDL) which will allow the Video feed generated to be sent to ground troops over a Rover Network, they could even control where the camera is pointed and indicate to the Pilot what they want targeted, this functionality is planned for Block 4. Also planned for EOTS Block 4 are short-wave infrared, high-definition television, an infrared marker and improved image detector resolution.
Helmet Mounted Display systems (HMD)
The F-35’s Helmet Mounted Display Systems provide pilots with situational awareness. All the information pilots need to complete their missions – airspeed, heading, altitude, targeting information and warnings – is projected on the helmet’s visor, rather than on a traditional Heads-up Display on the canopy widescreen.
The F-35’s DAS streams real-time imagery to the helmet from six infrared cameras mounted around the aircraft, allowing pilots to “look through” the airplane. Using this technology, pilots can see the entire environment surrounding them. The helmet also provides pilots with infrared night vision through the use of an integrated camera.
Communications, Navigation and Identification (CNI) Avionics System
The CNI uses Software-defined radio (SDR) technology, SDR uses reconfigurable RF hardware and computer processors to run software that produces a desired waveform, the CNI can manage over 27 different wave-forms. One of the new wave-forms is the MultiFunction Advanced Data Link(MADL) developed for the F-35 which has a very high data transfer rate (for video streaming etc.) and is very hard to intercept or jam, giving the aircraft “stealth” communications.
It also acts in a Daisy Chain fashion to operate over wide areas with other F-35s and command and control operating centers. The F-35 will have LPI/LPD Link-16 capability as well. With its full suite of communications it can give information to another aircraft enhancing their situational awareness, this allows an F-35 that has expended its munitions to continue to act as an AWACS, furthering network centric warfare.
If an F-35 sees a ballistic missile it can give that information to a naval vessel who can send an SM-6 after it with the F-35’s targeting data, extending the range of AEGIS, or it can provide geo-coordinate data on a vehicle somewhere and guide in artillery GPS shells/rockets or missiles(tomahawks) etc. With the AESA radar the communications system can send or receive very large amounts of data very quickly.
The AN/ASQ-239 “Barracuda” is an integrated Electronic Warfare (EW) and self-defense system. It is able to operate not just with other components within the aircraft such as the APG-81 but it can also operate with other F-35’s over MADL to perform EW operations together.
It’s able to precisely geo-locate emission locations hundreds of kilometers away, further then it’s radar can see and from there the APG-81 can be slaved to that data track and then detect and track the object with a very narrow beam, increasing power and detection on target while decreasing detection by other aircraft.
At close range or against targets using Jammers it is capable of narrowband interleaved search and track, which provides precise range and velocity that can then be used to shoot a missile without the need of the APG-81, allowing a 360 degree sphere of targeting other aircraft.
The Barracuda can refer to its data-banks of known emissions and identify the source vehicle or store it for future classification. Other features are false target generation and range-gate stealing, offensive EW is possible, a towed RF decoy is also a part of the package as is a MJU-68/B Flares system.
The F-35A carries an internal General Dynamics 25 mm GAU-22/A Gatling gun-style rotary cannon with 182 rounds of ammo above the engine inlet on the left side of the plane. The design of the GAU-22/A is a four barrel version of the GAU-12/U with higher accuracy. The rate of fire of the GAU-22/A is reduced to 3300 rounds per minute. The STOVL and carrier variants of the F-35 can be equiped with an external podded version of the GUA-22/A with 220 rounds of ammo on a dedicated centerline pylon. This teardrop gun pod will have stealth features. In the future, this same pod can be used for other equipment, such as electronic warfare equipment, reconnaissance equipment or possibly a rearward-facing radar.
Beacause the loading of external pylons increases the radar signature, the F-35 has two internal weapon bays with two hardpoints each. The two smaller inboard stations are designed to be equiped with the AIM-9 Sidewinder or AIM-120 AMRAAM air-to-air missiles. The two bigger outboard stations can be loaded with either air-to-air or air-to-surface weapons in the 2000 pounds class and smaller. Some of the weapons the F-35 can load on its outward stations are the AIM-120 AMRAAM, AIM-132 ASRAAM, the Joint Direct Attack Munition (JDAM) up to 2000 lbs, the Joint Stand off Weapon (JSOW), Brimstone anti-armor missiles and Cluster Munitions (WCMD). An exception is the STOVL variant which has a smaller weapon bay and can carry weapons in the 1000 pounds class and smaller.
The F-35 also has six external pylons, three under each wing. When stealth is no longer required to execute a mission, the external pylons are loaded with ordnance. When using these external hardpoints the CTOL and carrier variants can carry a weapon payload of up to 18,000 pounds, while the STOVL variant can only carry 15,000 pounds of payload. The inboard station is designed for up to 5000 lbs loads and can be used for various weapons or external fuel tanks. The midboard pylon is primarily intended for air-to-ground weapons and can carry up to 2500 lbs loads. The outboard station on each wing is a dedicated air-to-air station designed specifically for short-range infrared guided missiles of up to 300 lbs, like the AIM-9X Sidewinder.