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Airborne IRST properties and performance

Posted by picard578 on June 16, 2015

Introduction

IRST is a sensory device which uses IR (infrared) radiation for detection and targeting purposes. IR radiation has wavelength of 0,75 to 1.000 microns (micrometers), longer than wavelengths of color red in the visible spectrum (visible spectrum ranges from 0,39 to 0,7 microns, with violet at 0,4 and red at 0,7 microns). It is given off by all objects above absolute zero, though objects that are below average temperature of their surroundings will absorb far more IR radiation than they will give out. Unlike FLIR which is a targeting device, IRST can be used for initial detection as well.

Infrared radiation is divided into near infrared (0,75 – 1,4 microns), shortwave infrared (1,4 – 3 microns), midwave infrared (3 – 8 microns), longwave infrared (8 – 15 microns) and far infrared (15 – 1.000 microns). These have different properties. For example, glass is opaque to LWIR band but transparent to SWIR band, and significantly degradess image in MWIR band. MWIR sensors are far better at penetrating fog and clouds than other wavelengths, while LWIR sensors have superior atmospheric performance. As a result, while SWIR sensors can use glass, MWIR and LWIR sensors have to use exotic materials such as germanium and sapphire. 5-7 micron band suffers 100% absorption by water particles.

IR bands are also associated with temperatures of bodies producing radiation. Visible light is associated with temperatures above 1.000 *C. Next come IR bands: 0,7-4 microns (1.000 – 400 *C); 5-25 microns (400 – -150 *C) and 25-350 microns (this is a civilian, not military, division). Bodies at room temperature have radiation peak at around 10 microns, while 3-5 micron band is used in civilian applications for its effectiveness in tropical conditions.

In civillian purposes, astronomers use IR telescopes to penetrate dusty regions of space that block off visible light. NASA also has an airborne IR system – SOFIA (Stratospheric Observatory for Infrared Astronomy) which is flown at altitudes of over 41.000 ft, allowing 85% of the entire IR spectrum to reach it. Its service ceilling is 45.000 ft.

First IRSTs were deployed in 1950s on F-101, F-102 and F-106 interceptors. They were also used in F-8E, F-4 (B and C models only) and Swedish J-35A and J-35F-2 (1965-1967). However, they were primitive and were slaved to the radar, as opposed to modern-day independent systems. Any IR radiation falling on the sensor would generate a blip; consequential high false alarm rate meant that IRST was typically only used for (manual) radar targeting.

In 1960s and 1970s, Soviets deployed IRST units on their MiG-23, MiG-31, Su-27 and MiG-29 fighters. This was intended to provide passive BVR surveillance capability to fighters, and also as a way of countering Western advantage in radar technology and countermeasures. In fact, MiG-23 and MiG-31 interceptors were able to track the SR-71 recon aircraft from large distance, possibly up to 100 kilometers. This was despite the fact that the system was rather primitive, and that MiG-31s own skin and canopy would reach temperatures of over 760 degrees Celsius during the intercepts. MiG-23 had an IRST capable of detecting the F-16 at 35-40 km head on and 60 km from the rear. Later developments of Su-27 and MiG-29 families all have internal IRST.

General IRST properties

Due to relatively shorter wavelength, IRST is more sensitive than radar to adverse weather conditions. Much of the infrared radiation is absorbed by water vapor, carbon dioxide, methane and ozone. However, there are two wavelength “windows” in which very little infrared radiation is absorbed by the atmosphere. These windows are at 3-5 and 8-12 microns. Both modern IRSTs and modern IR missile seekers typically operate in both bands. 3-5 mM band is optimized for detection of aircraft in afterburner, while 8-12 mM band is better suited for detection of subsonic or supercruising aircraft through aerodynamic heating of skin. More specifically, afterburner exhaust plume is more prominent in midwave than in logwave band, with most emissions being in 2-8 mM wavelength band, while emissions from nonafterburning plume are only useful in 4,15-4,2 mM band. Blackbody radiation from a warm object is most prominent in 10-15 mM band, and only objects above ~300 K give appreciable MWIR emissions (still inferior to to LWIR band). As a result, LWIR detectors have good sensitivity against targets at ambient temperatures.

Unlike other IR bands, these two bands are comparatively altitude-insensitive when it comes to detection performance, as it can be seen from an IR absorpion chart in the next section; they are also less affected by water content. Comparing both bands, 3-5 mM band is less affected by aerosoil while 8-12 mM band has longer detection range and is less affected by clouds. Consequently, up until appearance of dual-band systems, midwave band was preferred for ground attack while longwave band was preferred for air-to-air usage.

While IRSTs can detect even relatively cool targets through thin cloud cover, detection range is reduced (more than it is in case of radar), and thicker clouds can significantly degrade detection range. As a result, IRST is most useful for air superiority fighters, which typically operate at 30.000 ft and above – well above normal cloud cover and in relatively thin atmosphere.* ** Only clouds typically present at altitudes above 8 km (~26.000 ft) are those of cirrus variety, which are IR transparent. While dense cumulonimbus clouds can reach extreme heights (60.000-75.000 ft), it is very rare; vast majority does not reach above 20.000 ft. They are also very hazardous to aircraft (especially those of stealth variety), with frequent lightning discharges and large hailstones ranging from 0,5 to 5 cm in diameter, which can damage aircraft’s skin.

contrails

Septemberimage10

Due to its passive nature and shorter wavelength, IRST has major advantages over radar regarding ID capabilities and ground attack performance due to increased resolution. In particular, IRST has better ability to project image of the target (to either cockpit displays or HMD), thus giving a fighter aircraft ability to ID other aircraft at longer ranges than would be possible with radar NCTR modes. IRST also has beter capability for differentiating aircraft in formation than radar does due to better angular resolution – possibly up to 40 times more accurate than radar’s. Still, IRST might have a regular magnified optical sight added for help with identification in clear weather.

Type and location of IRST is indicative of aircraft’s mission. Air superiority fighters will have dual band or longwave system positioned in front of the canopy on upper nose surface, while ground attack aircraft will have a dual band or midwave system positioned below the nose. Dual band system is preferable in both cases as it helps eliminate clutter, though it is not as beneficial for ground attack aircraft as it is for air superiority fighters.

Major advantage over the radar is that it cannot be easily jammed. As a result, actual tracking and engagement range of IRST can be expected to be greater than that of radar, even if latter has a major advantage in initial detection range. Jamming IRST with an infrared laser is a possibility (in theory), but it is very difficult if not impossible to pull off against a maneuvering aircraft. Operating modes are similar to radar: multiple target track (permitting engagement of multiple targets; similar in nature to radar’s track while scan), single target track and slaved acquisition (where IRST is slaved to another sensor, such as radar or RWR).

Being a passive sensor, IRST alone has issues with range finding. There are some workarounds. Obvious one is laser rangefinder, but being an active sensor it means that the target is warned of the impending attack (IRST still retains its passive surveillance advantage over the radar). Second one is triangulation, which can be done in several ways: datalinking two or more aircraft together, flying in a zig-zag / weaving pattern and measuring apparent target shift, or flying in straight line perpendicular to the target while doing the same. First two are usable against aircraft, while last one is only practical against ground-based targets. Target motion analysis can also be combined with atmospheric propagation model and/or apparent size of the target in order to provide a more accurate rangefinding, or these modes can be used as standalones. Radiance difference between target and the background is also a possibility. Doppler shift may be used to provide estimate of target’s speed relative to the fighters, which can be used to help with rangefinding; this is still questionable as it does not show up well at short distances, measurement may be impeded by the atmosphere, and is typically used by platforms and against targets with relatively predictable paths, which fighters are not. Exception is radar ranging, but in this case wavelength is already known beforehand to a great degree of precision. That being said, the only determinant for Doppler shift is relative speed of sensor compared to the object emitting radiation – and modern IR sensors used in astronomy can measure velocity of a star down to 1 meter per second (relative to Earth). For comparison, speed of sound at >=40.000 ft is 294,9 meters per second, and two closing fighters will be doing it at relative speeds between Mach 1,5 and 3,6. It is questionable wether Doppler shift is, or may, be used in airborne IRST.

It should be noted that while not knowing range of the target limits maximum engagement range, it does not preclude beyond visual range engagement, as missile can fly along the line of sight towards the target. This does create issues with end-game engagement, though a missile with active radar head is capable of pulling a lead, and even one with IR head might be capable of doing so albeit with less precision. Such engagement profile is in some ways superior to the classical one, as IRST’s greater angular precision will mean less possibility of a missile flying past the target without acquiring it.

Imaging IRST can also be used as a landing aid in no or poor visibility conditions (night, fog, rain etc.). While helpful for any aircraft, this is especially important for fighter and ground attack aircraft expected to operate from austere air strips.

It should be noted that IRSTs detection range is range at which probability of detection exceeds ~95% treshold, in clear-sky conditions. Actual range at which target is detected can be higher or lower. Also, heating of sensor due to friction during high-speed flight can degrade its performance somewhat.

While modern QWIP IRSTs offer the best performance, they have to be cooled to extremely low temperatures: 65 K is not uncommon. Quantum well is a potential well in which electrons are trapped. When excited, they can be ejected from the well, and produce current if external voltage is applied. QWIP photodetector / IRST can measure how much light comes from various sources by measuring the current. The longer the wavelength of light, the less energy the light has to give the electrons and the colder the detector must be to avoid excessive thermal excitations.

IRST can use scanning or staring array. Staring sensor uses one detecting element for each part of the image within field of view. This means that all detecting elements are simultaneously exposed to the image of the object, or a frame. Standard frame rate is 30 Hz, and dwell time is equal to the frame rate (1/30 of a second). Longer dwell time results in a more sensitive detector and less noise.

Scanning system can use a single element, which then sequentially scans the instantaneous field of view (determined by the aperture). Scanning system is typically a rotaring mirror. This system is cheaper than a staring array. Its output is serial as only IFOV is directed on the detector at any one time. Dwell time is determined by both frame rate and number of pixels in the image; a system with 30 Hz refresh rate and standard VGA monitor of 640×400 pixels has a dwell time of 1/7.680.000 od a second, which leads to increased noise in the system and reduced sensitivity.

(Note that a staring array still can be mounted in a turret which can scan the area in front of the aircraft).

*French Dassault Rafale has an optronics suite (IR+visual) and radar. Radar is considered primary air-to-ground sensor, while OSF is considered primary air-to-air sensor.

** F-35, a ground attack aircraft, will also typically fly at 30.000 ft during ingress/egress.

Counter-stealth performance

It is a general wisdom that IRST is of limited usefulness due to its sensitivity to adverse weather conditions. However, most modern stealth fighters (excepting the F-35 and J-31 tactical bombers) are intended to operate at high altitudes – above 50.000 ft – where ambient temperatures range from -30 to -60 degrees Celsius, which helps provide excellent contrast. Air at this altitude is also very dry, with 99,8% of the atmospheric water being below 45.000 ft. Combined with low air density and low aerosoil content, this means that there is very little atmospheric absorption of IR radiation. This applies especially to the longwave band, but detection capability is significantly improved in most bands as can be seen from the image below.

SofiaMauna

Stealth aircraft are designed to have certain IR signature reduction measures, but effectiveness of these is rather limited due to basic physics. To fly, aircraft has to overcome two basic forces: gravity and drag. Drag is created due to friction with air, compressibility effects and lift. To overcome gravity, aircraft needs lift. To generate lift, aircraft has to move forward and overcome drag. As a result, aircraft has to perform work – which creates heat. Indeed the largest IR sources on the fighter aircraft are its engines. Jet engines work by burning fuel in order to heat up huge quantities of air, which is then propelled out of the rear in order to push the aircraft forward. This leads to significant heat – engine itself is very hot (especially turbines), as is the exhaust nozzle. Engine heats up airframe surrounding it, which can be detected. Exhaust plume is also very hot, though much of the radiation is typically absorbed by the atmosphere (this depends on the altitude – refer to the image before this paragraph).

Other than the engines themselves and their exhaust, there are other sources of IR radiation. Any moving objects have to push the air out of the way. If object is fast – for example, an aircraft flying at high subsonic or supersonic speeds – air cannot move out of the way quickly enough. This leads to compression of the air in front of the aircraft, which in turn leads to heating of said air. At Mach 1,7, a supercruising fighter generates shock cones with stagnation temperature of 87 degrees Celsius; shock cone forms above Mach 0,8 and at around Mach 1 it achieves temperature of -13 degrees Celsius. Shock cone also increases frontal area presented to the sensor about 10 times (its diameter depends largely on aircraft’s wing span). As the air moves out of the way for the aircraft, it also creates significant friction with the aircraft itself, leading to heating of the aircraft’s skin. In a jet fighter, hottest parts of the airframe other than the engine nozzles are tip of the nose, front of the canopy, as well as leading edges (of wings, tail(s) and air intakes).

hotspot_jet

As mentioned before, MiG-31 would heat up to 760 degrees Celsius during intercepts due to aerodynamic heating alone. Airframe temperature due to friction can reach -29 degrees Celsius at Mach 0,8, 54,4 degrees Celsius at Mach 1,6, 83,3 degrees Celsius at Mach 1,8 and 116,8 degrees Celsius at Mach 2,0. F-22 has two pitot tubes – one at each side of the nose – which are heated to 270* C during flight operations to prevent them from icing at high altitude. Avionics have to be cooled – especially radar. Heat exhaust is typically located at fighter’s upper surface – just behind the cockpit in Gripen, and about one canopy length behind it for the F-22. F-35 is in even worse situation since it uses fuel as a coolant, and said fuel completely surrounds its engine. This has the effect of increasing its IR signature as well as the possibility of bursting into flames if hit.

These temperatures can be compared to the ambient air (Standard US Atmosphere). F-22 achieves maximum cruise speed of Mach 1,72 at ~38.000 ft without afterburner, and maximum speed of Mach 2,0 at between 38.000 and 58.000 ft with afterburner. Above cca 53.000 ft it requires afterburner to fly, and can achieve maximum altitude of ~64.000 ft, where it is limited to maximum speed of Mach 1,6-1,8. Ambient temperature is -44,4 *C at 30.000 ft, -54,2 *C at 35.000 ft, -56,5 *C at 40.000 ft to 60.000 ft, and -55,2 *C at 70.000 ft. That is to say, difference between shock cone of a M 1,7 F-22 and ambient air will be around 130-145 * C, while temperature difference between airframe and ambient air will be cca 111 * C at Mach 1,6 and cca 172 * C at Mach 2,0. At Mach 1 difference will be 31-44 * C between shock cone and the ambient air; difference in temperature between airframe and ambient air will be 15-27 * C at Mach 0,8.

IRST sensor of Dassault Rafale’s OSF can, at 20.000 ft, detect a subsonic fighter-sized target at 80 km from the front and 130 km from the rear. At low altitude, range from the rear is 110 km, which would indicate frontal range of 68 km. F-22 achieves supercruise speed of Mach 1,72-1,75 at 38.000 ft. Assuming similar increase in range between 20.000 and 40.000 ft, OSF should be able to detect the subsonic F-22 at distance of 90-95 km from the front and 145-155 km from the rear. If F-22 is supercruising at Mach 1,70 and 40.000 ft (about the limit of its supercruise performance at that altitude), range increases to 270-285 km from the front and 435-465 km from the rear.

While fighter’s IR signature can be reduced by reducing speed, such course of action also has the effect of reducing one’s own weapons range, as well as making a rear-quarter surprise more likely. In either case, fighter will get detected by modern QWIP IRST before it reaches missile effective range (10-40 km for AIM-120D at most, and can be as low as 2 km).

It is possible to apply IR absorbent paints to a fighter in order to reduce IR emissions from systems inside it. This, at best, does not have any impact on aerodynamic heating. Some IR absorbent paints cause more friction than would otherwise be the case, increasing aerodynamic heating. RAM coatings also can increase friction. While it is not a significant factor in MWIR band, LWIR detectors can detect aircraft by detecting sunshine reflections from its surfaces, such as canopy.

Modern IRST systems can even detect missile launch from its nose cone heating – this is in fact a significant advantage for IR MAWS, as UV MAWS cannot detect missiles that have spent fuel. They are also sensitive enough for planets, birds, and (in air-to-ground) barbecue grills to be sources of clutter.

Note that even if an object is at the exact same temperature as its environment, it still emits blackbody radiation, most of it at longer wavelengths.

Tactical impact

Unlike radar, IRST is primarily a passive system. This allows a fighter aircraft, or a fighter group, to detect and track the enemy without latter being aware of their presence, thus gaining a significant initial advantage in the OODA loop. Even when the enemy is aware of the fighter’s presence, he has no way of knowing wether he has been detected, or is being targeted, until a significant shift in fighters’ posture (such as painting target with a rangefinder or shifting flight path or formation). For comparison, just turning on the radar warns the aircraft in very large area of scanning fighter’s presence – and said area is far larger than one covered by the radar. Not only does it give away fighter’s presence, but if the enemy has good enough listening equipment, it is possible to triangulate location and even identify the target through its unique radar signals. Even radio communications and datalinks can serve the same purpose.

If the enemy is using radar, it is possible to use data from radar warner to generate a bearing, after which IRST can be used in a “stare” mode – continuous track, during which photon impacts are combined over prolonged timeframe to detect a target at greater distances than would normally be possible. This mode is also present in radar systems, and like IRST, radar also has to be cued by other sensors to make use of it. But while using radar in such a manner basically guarantees than the enemy with a competent RWR will detect radar transmissions, IRST is undetectable. Even a short radar burst can allow the passive fighter to generate such bearing, albeit it will somewhat limit the precision.

If radars are jammed, or more likely turned off for fear of detection, first indication of IRST-equipped fighter’s presence that the enemy aircraft will get may be alarm from a missile warning system (or radar warning system if missile is using an active seeker), thus allowing only a short time for defensive reaction. (Simulated trials of ECR-90 have shown that its airborne detection range could be cut to less than 9 kilometers by jamming). If both sides have IRST, it comes down to sensor quality and IR signature differences.

Aircraft equipped with IRST, and using IR MAWS, can remain completely silent during the mission. If the enemy has no IRST, then he will have to turn on his own radar(s), allowing the passive aircraft excellent situational awareness, well beyond what using radar in addition to IRST would allow. Further, active usage of radar will allow geolocation of radar emitters, allowing the passive fighter to use IRST to engage such targets with high precision – thus gaining a “see first, strike first” capability. IRST-equipped aircraft is also not vulnerable to anti-radiation missiles. (Note that such missiles are not very hard to make, with basically all air-to-air engagement radars being in X band).

IRSTs shortcomings can be compensated for by using datalinks to network the fighter with other assets, such as other IRST-equipped fighters and radar-equipped AWACS. As a result, radar is not the primary onboard sensor any more, and is not actually even required.

Using datalink from AWACS (though AWACS is unlikely to survive for long in a shooting war) or ground radars, fighter can then approach the enemy from side or rear, in order to prevent detection by enemy’s own radar and maximize IRSTs detection range. Once target is acquired on IRST, fighter can pursue engagement completely independently. Of course, if enemy fighter uses its own radar, no AWACS is required. It should be noted that most, possibly all, fighter aircraft today lack the datalink capable of transferring amount of data necessary for a firing solution. Even if such datalink is deployed, it will be easy to jam. As a result, fighters have to rely on onboard sensors to create a firing solution (when Rafale shot down a target at 6 o’clock, shot was done with onboard sensors and within visual range; F-35 may have a similar capability).

Large radar-based fighters – such as the F-15, F-22, Flanker variants – can act as AWACS of sorts, providing radar image to smaller IRST-only fighters, which can then use such image to achieve optimal position for a surprise attack. This in turn will allow IRST-equipped fighters to focus the IRST and achieve detection ranges larger than could normally be achieved. Even if radars are jammed, radar-based fighters should be able to roughly tell positions of enemy fighters, unless DRFM, active cancellation or standoff jamming is used. Using IRST to generate a firing solution, and then launching an IR BVRAAM or ramjet RF BVRAAM (or, ideally, a ramjet IR BVRAAM, though such missile does not exist in Western inventory) at a surprised opponent will allow far higher kill probabilities than using an obvious radar for firing solution.

Still, using an AWACS with a huge IRST plus extensive ESM arrays might allow the same tactics without a drawback of warning the enemy that he has been detected, and without suffering vulnerability to decoys and jamming that radar has. Additional advantage of such system is that its effectiveness will not be significantly degraded even against VLO targets. On the other hand, while bad weather degrades IRSTs performance, it also degrades performance of stealth coatings (assuming that stealth fighters can safely enter storm clouds), thus combining radar AWACS with IRST-equipped fighters does make some sense, as does using both types of AWACS.

IRST is the best solution for engaging stealthy aircraft and cruise missiles. As it can be seen from the previous section, is impossible to significantly reduce IR signature of a high-speed, highly maneuverable aircraft, and even low-performance aircraft that do have very extensive IR signature reduction measures are still detectable at large distances by new QWIP imaging IRSTs. Even against “legacy” aircraft its is a better choice than radar, as radar cannot separate valid contacts from decoys except at very short range – especially if it is being jammed. As a result, only IRST-equipped fighters can effectively engage modern fighters at beyond visual range.

IRST can be used as a relatively cheap way of turning an old, possibly even WVR-only, platform into one capable of BVR combat. With PIRATE + MICA IR combination, even an old F-86 would gain a capability to shoot down enemy fighters from beyond visual range (that being said, issues of low cruise speed, deficient acceleration by today’s standards and no defense suite at all would remain, and would mean that even against the F-35, F-86 would not achieve positive kill/loss ratio).

Analytic simulations indicate that an IRST-equipped aircraft will have 230% better exchange ratio than a non-IRST equipped aircraft against a “legacy” target, and 370% better against a LO target.

Specific IRST systems

PIRATE

PIRATE is used by Eurofighter Typhoon, and it entered service in 2007. Its lead contractor is Selex ES. Selex holds the bulk of Western experience in IRST systems, and is also a sole supplier of the Skyward G IRST. Thales, another member of the Eurofirst consortium, also has extensive experience in the area.

PIRATE is a dual-band system (3-5 and 8-10 microns), combining long range detection capability of the longwave IRST with high resolution and all-weather performance of midwave one. It can track more than 200 targets, and has 140* field of regard in azimuth, with -15* depression angle. Sensor head weights 48 kg, with 60 kg (?) total weight.

Detection range against a subsonic fighter-sized target is 90 km from the front and 145 km from the rear. It has an ID range of 40 km, and can track a maximum of 200 targets. It is stated to be capable of passive ranging. Its ability to provide infrared image (which can be shown on cockpit displays and HMD) can, aside for ID purposes, also be used to help with flight operation in low visibility conditions.

(Note that range figures for Western IRSTs are most likely measured/estimated against Su-27, a massive aircraft with no IR signature reduction measures.)

Skyward G

Skyward G is a new IRST intended for use in Gripen E/F, and represents a technological improvement (in both hardware and software) over older PIRATE IRST it is based on. It is a staring imaging IRST. It is also smaller, with sensor head weighting 30 kg. Like PIRATE, it is a dual-band system covering midwave and longwave infrared bands, and can provide IR image on pilot’s helmet. Scan coverage is 160* in azimuth and 60* in elevation.

Skyward is stated to be capable of detecting all aircraft flying faster than 300-400 kts from skin friction alone – irrespective of any exhaust plume or engine IR signature reduction measures. Range for such detection is unstated.

OSF

OSF is an optical sensors suite used by Dassault Rafale. It consists of an IRST sensor and a video camera. Like PIRATE, its IR sensor is dual-band, using 3-5 and 8-12 micron bands.

Detection range against a subsonic fighter-sized target is 80 km from the front and 130 km from the rear (at 20.000 ft; 110 km at low altitude). Optical camera has ID range of 45 km, while IRST has an ID range of 40 (?) km. It was reported to have locked on a turboprop Transall through thin cloud cover.

EOTS

EOTS is a staring IR sensor. Unlike above IRST systems, it is primarily intended for ground attack, as a replacement for various IR targeting pods. As a result, it is a single-channel midwave IR system, limiting its detection performance against nonafterburning targets and in air-to-air role but providing all-weather performance. It weights 200 lbs / 90,7 kg.

It is also obsolete when compared to modern IR pods used by US Navy (in particular, newest versions of Sniper and Litening pods), being more than a decade old as of 2015. In fact, it is basically an internal version of Sniper XR pod which entered service in 2006, and has low resolution and detection range when compared to the Legion pod. From Sniper XR demo, it appears that identification range is 24 kilometers against fighter aircraft, though the aircraft in question was on the ground, and 45 kilometers against an airborne business jet, showing ID performance at most comparable to PIRATE. This suggests lower maximum detection range as PIRATE likely uses midwave channel for identification, but also has longer-ranged longwave channel. That being said, actual detection range performance may be better than suggested here. Its configuration also allows it quicker scan speeds than with traditional IRSTs.

OLS-27

OLS-27 is used on Su-27 fighter, and has a maximum range of 70 km.

OLS-30

OLS-30 is used on Su-30 fighters. Maximum detection range might be as high as 90 km, and weights 200 kg.

OLS-35

OLS-35 is a scanning array IRST used on Su-35 fighters. Detection range is 50 km head on and 90 km from the rear against a subsonic fighter-sized target. It can track 4 targets. Sensor head weights 60 kg.

OLS-50

OLS-50 is IRST for T-50/PAK FA fighter. It is the first QWIP system deployed on Russian fighters, which suggests far higher detection range than earlier systems as well as the ability to identify targets.

IRST-21

IRST-21 is a podded system in use with US military. It has field of regard of +-70 degrees (140 degrees) in both azimuth and elevation, and total weight of 67-83 kg. Like other Western IRST systems (and presumably most Russian systems listed), it is capable of generating weapons-quality tracks.

Conclusion

While historically IRST had major performance issues, modern IRST systems, especially Western ones, have mostly solved these issues. As a result, IRST can be expected to become a primary sensor in any air war between competent opponents, for the same reasons as those that led to night vision googles being used for night fighting in place of flashlights.

While US Department of Defense has a very long history of being “late to the party” when it comes to introducing simple, yet effective (even transformative) systems*, US military is currently taking baby steps to rectifying its lag in development and application of airborne IR sensors. This can be clearly seen from the F-35s inbuilt IRST (though that decision was only made on insistence of US Navy, which was also the first service to introduce the Legion pod, and generally has better understanding of passive IR systems than USAF**), and procurement of IR pods for the F-15C, F-16 and F-18 fleets. Legion pod procured is capable of generating weapons track. US Navy is also the service that initiated development of AIM-9X Block III, which is basically a BVR missile, with a range of 42 km.

One of reasons why United States have not put funds into developing IRST, and are even now using almost exclusively systems geared for air-to-ground performance that happen to have air-to-air option, is that IRST was seen as a threat to the AWACS program, and later on also to stealth fighters. Both of these were high-budget programs that USAF could not allow to disappear. With average price of 1 million USD per unit, it would take only 3,2 billion USD to equip the entire US inventory of tactical aircraft with modern IRST systems. Allowing it to threaten the multi-billion AWACS or stealth aircraft programmes was simply unacceptable.*** For this reason, USAF is still acting as if IR sensors have not advanced past Vietnam-era sensors with their range, weather and targeting limitations. Same reason is also likely behind the decision to retire the IRST-equipped F-14 just before the F-22 started entering service (F-14s were retired in mid-2006, while the F-22 started entering service in 2007).

This might be changing as USAF agressors are starting to use IR sensors during Red Flag exercises. US’ Northrop Grumman has also signed a deal with SELEX which will bring Europe’s more advanced IRST technology to United States. This will help overcome US technological lag in field of IR systems when compared to Europe.

* Examples are assault rifles, carrier catapults, IR sensors, helmet mounted sights, HOBS IR missiles.

** US Navy was also the first service to deploy IR Sidewinder missile in 1956. US Air Force deployed a Falcon missile the same year, but it had both IR and RF variant, and unlike Sidewinder, it was primarily intended for bomber self-defense and not for usage on fighters. Even though it was later deployed on fighter aircraft as well, USN Sidewinder proved superior and became preeminent US IR air-to-air missile.

*** E-3 Sentry program cost is 26,73 billion USD, F-22 program cost is 79,48 billion USD and F-35 program cost is estimated at 323 billion USD, though it is likely to be higher.

Ye cannae change the laws of physics! – Scotty

Further reading

http://fas.org/man/dod-101/navy/docs/es310/EO_image/EO_Image.htm

http://foxtrotalpha.jalopnik.com/infrared-search-and-track-systems-and-the-future-of-the-1691441747

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83 Responses to “Airborne IRST properties and performance”

  1. Chris said

    I think I mentioned this before, but I think one idea for constant sky awareness might be to launch many very small and cheap drones armed with nothing more than an IRST, maybe a 1-2 sidewinders if they can fit.

    You could buy a lot of these drones and they could give you some pretty good situational awareness.

    Like

    • picard578 said

      Yes, that could work. A turboprop / piston engined UAV with IRST and large wing could achieve excellent loiter time, range and altitude. You would still need manned recon platforms, but such UAVs would be very useful for quite few purposes.

      Like

  2. Foxhound said

    Thank you very much Picard for your article.

    Like

  3. Chris said

    One more though about the FLX – as far as keeping the aircraft, an interesting question becomes how long to keep it versus getting a new one.

    Earlier, I said, assume an 8000 hour life. The interesting thing is of course that the aircraft does not suddenly “die” at 8000 hours. It just needs more and more maintenance. The question becomes, at how many hours does it become “worth it” to get a new aircraft? That I think is where the question is.

    Apparently the oldest Boeing 747s in service are as old as 120,000 hours of flight. It’s not a direct comparison of course with a fighter (shorter sorties so more frequent landing/takeoffs) plus much higher stresses on the airframe, but it’s an interesting question.

    The USAF and USN have their share of issues. With the F-35 taking up so much money, there are now planes with over 10000 hours of flight.

    http://foxtrotalpha.jalopnik.com/blue-angel-f-a-18-hornets-shed-parts-in-flight-twice-in-1709836712

    There are similar stories around about the F-15 and F-16.

    Like

    • picard578 said

      “Earlier, I said, assume an 8000 hour life. The interesting thing is of course that the aircraft does not suddenly “die” at 8000 hours. It just needs more and more maintenance. The question becomes, at how many hours does it become “worth it” to get a new aircraft? That I think is where the question is.”

      8.000 hours is timespan after which cracks start appearing in airframe. IF you don’t mind repairing them, airframe can potentially last two or three times as long as that.

      “There are similar stories around about the F-15 and F-16.”

      Yeah. IIRC, there was a time when plane literally started falling apart mid-air due to age.

      Like

    • Chris said

      Yeah I think they will have to be retired from front line service.

      They might be able to last a couple of thousand hours as training aircraft, but I suppose one issue is that you want your new pilots to have a large number of flight hours. If you accumulate a large number of aged aircraft, it might be useful though.

      That and it could be useful for training your maintenance crew. I think one thing we should consider is that maintenance crew are every bit as important as pilots – especially when it comes to repairing and maintaining aircraft.

      Like

      • picard578 said

        Problem with aged airframes, especially with high-agility platforms, is that there is a large accumulation of cracks – some of them almost invisible. So while you can extend aircraft lifetime past the designed lifetime if you want, it is not exactly the smartest thing to do on a regular basis as it will demand frequent inspections – else you risk aircraft literally falling apart midair.

        Like

      • Chris said

        Basically only good for training for maintenance teams during peacetime – and as they’ve been historically used, maybe target practice.

        Yeah for sure withdraw from front-line service.

        But it means that an aircraft has to be replaceable, which I guess means a cheap airframe like the FLX.

        Earlier you mentioned the sensors might be reusable. I’m not sure. Look at for example the development of IRST. Russian for example, OLS-30 to OLS-35 and now we’re seeing OLS-50. 10 years from now, I would imagine there would be an OLS-55 (or whatever they call it), and the Eurocanards at least will all get major IRST upgrades. The US may or may not embrace IRST completely.

        But on the other hand, the sheer volume of production will probably decrease marginal costs for spare parts and airframes. Plus software will be spread over a larger number of airframes, which may make the unit costs more bearable in that regard as well, although software will have to be updated with new systems.

        Like

        • picard578 said

          “But it means that an aircraft has to be replaceable, which I guess means a cheap airframe like the FLX. ”

          Indeed.

          “Earlier you mentioned the sensors might be reusable. I’m not sure. Look at for example the development of IRST. Russian for example, OLS-30 to OLS-35 and now we’re seeing OLS-50. 10 years from now, I would imagine there would be an OLS-55 (or whatever they call it), and the Eurocanards at least will all get major IRST upgrades. The US may or may not embrace IRST completely. ”

          Which does not mean it cannot be reused in UAVs/UCAVs or some similar low-cost application. If it isn’t the best, it doesn’t mean it is not good enough for some things.

          “But on the other hand, the sheer volume of production will probably decrease marginal costs for spare parts and airframes. Plus software will be spread over a larger number of airframes, which may make the unit costs more bearable in that regard as well, although software will have to be updated with new systems.”

          Agreed. It may also make maintenance easier, and will definetly make deployments easier as countries will be able to pool resources as I have envisioned FLX being used across NATO.

          Like

      • Chris said

        That could work – a cheap UAV or something like that.

        One option may be to open source the software and see what individual nations can build. Sure enemies might get it, but they still need to build the airplane and most of all, have good pilots to win.

        Like

  4. Silavite said

    An IRST-type AWACS aircraft sounds very interesting. How much would the sensors on an IRST AWACS differ from the SOFIA’s infared telescope?

    Also, it’s a bit off topic, but do you prefer Scotty or La Forge? (I prefer Scotty personally)

    Like

    • picard578 said

      “How much would the sensors on an IRST AWACS differ from the SOFIA’s infared telescope?”

      Well, you’d probably want greater field of view and especially greater field of regard. So either a turreted installation or two installations, one on each side of the aircraft.

      “Also, it’s a bit off topic, but do you prefer Scotty or La Forge? (I prefer Scotty personally)”

      Scotty. *Especially* after he got older.

      Like

  5. Foxhound said

    Hello Picard.

    French Rafale avalaibility could be only 44 aircraft able to fly.

    Le fleuron de l’aviation française qui représente une bonne partie du total de la flotte avec l’Alphajet (93 et 136 appareils) ne déroge pas à la règle, seulement 44 Rafales sont prêts à décoller sur le champ

    http://www.liberation.fr/economie/2015/06/19/armee-de-l-air-la-flotte-francaise-en-partie-clouee-au-sol_1333006

    This is what french defense ministry admit, the real figure must be lower, must be less than 30, because this kind of information are all classified. It is noteworthy to recall that indian SU-30 MKI’s fleet’s availlability is around 40%. I’ve recently seen an information about the fleet of german EFA Typhoon-british must be the same, or worse-, is less than 10%.

    seulement 8 avions de chasse Eurofighter sur les 109 exemplaires en service seraient en état de voler.
    http://www.opex360.com/2014/08/27/lhebdomadaire-der-spiegel-decrit-aviation-militaire-allemande-dans-etat-lamentable/#l0itemo8A7jpsJFK.99

    In fact all these news asserts what you often say, more an aircraft is complex, more this aircraft is expensive, less it is available. And the availability becomes a critical issue.
    Seeing this, how it is possible to believe what US DOD statement about the fact that the F-22 is available at a rate of 69%. F-22 as you showed us has vector thrust engine, special expensive coat-several dozens thousands of rivets-, moreover with an avionic very complex. The US figure of 69% of availability is simply laughable, if not ridiculous.

    PS: A Picard,
    je ne sais pas si vous êtes francophone, mais je suis subjugué par la qualité et le soin de votre travail, c’est un des sites les plus complets sur le sujet. Grand merci pour votre trés précieux travail. Concernant le lien de Libération si vous ne pouvez accéder à l’article envoyez moi un email, et je vous en ferai part.
    Bien à vous.

    Like

    • picard578 said

      IIRC, USAF has its own special way of counting aircraft avaliability, which artificially inflates numbers. It might also have to do with their larger budget, or they may be lying.

      Thanks a lot!

      ——
      P.S.
      I’m not French, I’m Croatian. I do understand a little of French as it is quite similar to English, but overall I use Google Translate, French > English (as I did right now).

      Like

      • Foxhound said

        Indeed, we assume all that US has huge military budget, but huge budget does not necessary mean infinite. There are many other departments that need money. The fundamental question that I want to ask.

        Could 20 or 30 expensive F-22 overcome 300-500 Mig-21 -equipped as you demonstrated with IRST- ? Could 10 Typhoon overcome 100 Mig-21 easy maintainable, and available ? From your several articles I could ask this question.

        Like

        • picard578 said

          “Could 20 or 30 expensive F-22 overcome 300-500 Mig-21 -equipped as you demonstrated with IRST- ? Could 10 Typhoon overcome 100 Mig-21 easy maintainable, and available ?”

          No, and no. Typically, 3:1 is the greatest difference that advantage in technological quality could compensate for. Which is why I believe Gripen to be the best Western fighter (and likely the best in the world): easy to maintain, cheap to buy and operate, reliable, can fly from roads (and possibly even dirt strips), stealthy (in visual and IR spectrum), agile. Basically, a combination of best characteristics of Western and Eastern fighters rolled into one. Only problems are lack of IRST and insufficient cockpit visibility.

          Like

      • Chris said

        It makes you wonder if about a simple modern piston or turboprop aircraft. Could a modern P-51 (with a more efficient engine) or Fw-190 win through sheer numbers?

        Like

        • picard578 said

          Yes. No. Maybe. There is large number of variables to consider. Modern jet fighters have far higher cruise speeds and service ceillings than piston fighters did. Piston fighters could circle enemy air fields, but air defences are likely to be too strong.

          That being said, in my NATO air forces proposals you always have large numbers of turbofan CAS fighters and turboprop AFAC/COIN/CAS aircraft. And they all can be armed with Sidewinders.

          Like

      • Chris said

        The next logical question then would be something like a more “modern” F-86 (ex: with modern engines). Thousands were bought and if production ramped up, thousands could be bought again.

        But yeah, there are simply too many variables to consider.

        Like

    • Chris said

      One of the things that I have become convinced about with military hardware is to consider opening up the data.

      Also, open up the reasons why – it might lead to ideas.

      An analogy – I have noticed that in computer gaming, one of the most important things nowadays is to open up the game for modding. Often mods are better than the games themselves. The best LOTR RTS for example is not a game, but a mod – Third Age Total War, which has tons of sub mods that you can install. The best Star Trek RTS too is a mod of Sins of a Solar Empire (there’s actually 2 – Sacrifice of the Angels 2, which tries to replicate an authentic Star Trek experience and Armada 3, which is more gameplay focused). Try both to see (if you are a gamer).

      Like

    • Chris said

      Also, if it means something, the B2 bomber apparently averages only 1 sortie per month. That should give you an idea of availability.

      Like

    • We must distinct two things:
      Opeartional availability.
      Every days availability.

      From what i know operational availability in recent conflicts (Mali, Lybia, daesh, Afgha,..) and permanent quick air response (“permanence opérationnelle”) in France is somthing like 90 or 95% for the Rafale
      The best ever known for a fighter in the french air force’s history.

      Every days availability for training and so on, is poor, ok.
      But its’ not a question of aircraft quality.
      it’s just a question of money.
      France decided to have very few spare parts. So we use cannabilism.
      More, France decided to preserve hours potential of the Rafale, in consequence, some of them are already “sleeping” at Chateaudun airbase, waiting to be reactived in case of…

      This being said, plus a none aeronautics specialist news paper “Libération”, plus a french air force pushing the governement to have more money for more aircrafts and more flight hours leads to such a poor number.

      (Numbers are nothing without context and explanation.)

      Like

  6. Foxhound said

    Thx for your quick responses.
    However, does the Grippen have a better availability ? As I think Swedish are not supermen-contrary to the americans 🙂 -, I doubt they could do better than the rest of world. If Grippen is very good fighter, I don’t doubt a second, nevertheless, it has not the same availability as Viggen or Draken.
    I think we have the same problem that said Pierre Sprey, a big fighter was built from a radar, and the radar became more and more big, great powers built a bigger fighter around the radar that effectiveness is still doubtful nowadays. More the fighters become biggers, more they were complex, more they were heavy, more they are expensive, less they are available.
    If B2 availability is one fly/month where would be its effectiveness ?

    Like

    • picard578 said

      “However, does the Grippen have a better availability ? As I think Swedish are not supermen-contrary to the americans 🙂 -, I doubt they could do better than the rest of world.”

      Gripen is a simple single-engined fighter designed for ease of maintenance and low operating cost. That makes it unique as far as Western designs go.

      “I think we have the same problem that said Pierre Sprey, a big fighter was built from a radar, and the radar became more and more big, great powers built a bigger fighter around the radar that effectiveness is still doubtful nowadays. More the fighters become biggers, more they were complex, more they were heavy, more they are expensive, less they are available.”

      Agreed. And the worst part is that today there are smaller sensors – such as IRST – that can replace radar in air-to-air combat. But institutional inertia being what it is…

      Like

      • Foxhound said

        Sorry for grammar errors, in wordpress, we cannot edit.

        I mean
        More the fighters become biggers, more they are complex, more they are heavy, more they are expensive, less they are available.

        Thank you very much for your explanations. I will finish my post by asking you a last request please. If you want, could you post a subject about Anti Aircraft Artillerie versus modern bombing. You posted an excellent article about JDAM, nevertheless, I wish you post about artillerie like AZP S-60, M1938, ZPU, Oerlikon, M61 Vulcan, ZSU, etc….
        It seems that untill now US, are dreading this low level hardware, and if they did not deter different US Air campaigns, they heavily hampered them. I was completly amazed by your assertions in the differents articles you posted, because they are all near the truth. You said for example that during the gulf war I, US attacked 17 critical targets, and just only one was indeed destroyed. During the Kossovo war you said -and it is correct- that only 14 tanks, 18 armored vehicles, 20 cannons were destroyed. On 80 SAM batteries, only 3 were destroyed. I suspected the effectiveness of anti aircraft artillerie that heavily hampered all US raids. Now in Yemen, Israel, and Saudi Arabia bombed, but without any clear results, Israel bombed Hezbollah, and Hamas in 2006, 2012, and 2014 with the same pitiable results. I suspect too the anti aircraft artillerie that hampered. For that reason I wish to understand the effect of amnunitions like HE-T, HEI-T, AHEAD, FAPDS etc…at which distance they could be capable ? 5.000 M ? 6.000 Meters ? What is the wind, dust, snow, rain, effect for example ? A SAM as you explained in previous articles, could be easily dodged, and could be jammed with +/- difficulties, but the cannons, it is near impossible to dodge them.

        Thx very much.

        PS: North Korea has built up a new anti aircraft 30 mm gatling gun, with an effective range around 5.000 Meters.

        Like

        • picard578 said

          “It seems that untill now US, are dreading this low level hardware, and if they did not deter different US Air campaigns, they heavily hampered them. (…) I suspected the effectiveness of anti aircraft artillerie that heavily hampered all US raids. ”

          That is because US don’t have any aircraft that can survive AAA except the A-10, but also because of historical infatuation with high-altitude bombing which made US intentionally overestimate effectiveness of AAA against low-level CAS aircraft (it is true that optically-aimed AAA and IR MANPADS are most effective air defense systems, but not to an extent that they make low-level aircraft unfeasible).

          “but the cannons, it is near impossible to dodge them.”

          Depends on type and distance. Optically aimed AAA provides no warning and cannot be dodged within few km, whereas radar aimed AAA betrays its presence and can be jammed.

          Like

      • Chris said

        I have wondered at times if an IR aimed AAA might be a viable solution. The obvious solution would be to use flares, but you’d run out (it’s not like trying to dodge a missile – you’re trying to dodge something constantly aimed at you).

        If this could be combined with a laser rangefinder to plot a firing solution, this could be quite dangerous.

        Like

  7. Foxhound said

    Thx for your reply.
    It would be interesting if you could do a post, or an article about AAA, and AAA’ ammunitions like HE-T, HEI-T, AHEAD, FAPDS etc…
    Because once an amno fired will have to overcome the gravity, the air drag, the wind, the rain, the snow, humidity, etc..
    For that reason we need somehow your expertise. 🙂

    Thx for your help.

    Like

  8. Foxhound said

    To Chris and Picard about IR aimed AAA.

    A few years ago, I’ve seen a video about new indigenous iranian version of Oerlikon with IR-with IRST too ?-. They called SAER if I recall. Moreover, it is well known that SA-19 Grison and SA-22 Greyhound have already passive radar, and maybe a kind of IRST, as in S-300, S-400. If indeed we thought all about this subject, others had already thought a long time ago, especially soviet as it rely on their huge army.
    But my straightforward question is :
    Could for example -57, 35, 37, 23, 25, and 20 mm- HEI-T, or AP-T ammunition able to penetrate and explode into a fighter-bomber-hence down it-, or bomber at 6.000 Meters or above ? If yes -I think it could be, with modern, and progress design of ammunitions- I understand why all air campaign are long, laborious, with in the best cases mixed results, but in most of the case a very limited effect, if not pitiable, to not say a null impact in the batlefield.
    The best example is the american air campaign in Iraq and Syria against DAECH terrorists. US coalition used a panel of fighter-bombers as : F-15, F-16, F-18, and F-22, until now we are realizing that the results are limited, if not without impact on the battlefield.

    As Picard described the F-22 is equipped with complex sensors, radar 3d, JDAM bombs, cannons, in fact this aircraft is the finial of US air Force. Nevertheless, it has no results on the battlefield against DAECH.

    Like

    • picard578 said

      “As Picard described the F-22 is equipped with complex sensors, radar 3d, JDAM bombs, cannons, in fact this aircraft is the finial of US air Force. Nevertheless, it has no results on the battlefield against DAECH.”

      That’s because you can only defeat a ground force with another ground force. Which means that the only aircraft whose sorties against ISIS are not, more or less, a complete waste of time and money is the A-10, especially when flown in support of Peshmerga and Iraqi Army. All other aircraft deployed could have likely stayed in CONUS without changing anything.

      Like

      • Foxhound said

        Next we could exchange about the so-called effectiveness, and the hype around the A-10. Contrary to what US officials asserts, they tried to use their A-10 since the beginning against the so-called Islamic States. The problem is the fact that Turkey with some other NATO, and arab countries provided DAECH terrorists with heavy and lethal weapons in substantial way, especially AAA that forbid any CAS. Sending now an A-10 where there many batteries Oerlikon, S-60, M-1939 with their special HE-T, AP-T, etc… ammunitions, we are sure to retrieve the A-10 in smoky wreckages, and US pilots as chopped steak. But, do not make mistake, US DOD could not say all, because there are many informations classified. If I asked you about this sensitive subject, I know that there are many things that are not obvious.

        The A-10 is supposed to be immunized against 23 mm caliber, as far as possible not much shots. A thing is sure if there are several batteries of ZSU 23, or ZPU that fire in a sustain way, the A-10 like others aircrafts could not do miracles. Moreover against the redoutable and cheap M-1939 37 mm caliber the A-10 could do nothing. No use to talk about Oerlikon, or AZP S-60. I think you must be know what I said more than me. I read many of your post in scrutiny’s way, and I recall when you talked about the pitiable results of air campaign against Serbia. If the A-10 was the miracle weapon, every country in the world will buy it, at first Israel, but this is not the case.

        Regards.

        Like

        • picard578 said

          “Contrary to what US officials asserts, they tried to use their A-10 since the beginning against the so-called Islamic States. The problem is the fact that Turkey with some other NATO, and arab countries provided DAECH terrorists with heavy and lethal weapons in substantial way, especially AAA that forbid any CAS. Sending now an A-10 where there many batteries Oerlikon, S-60, M-1939 with their special HE-T, AP-T, etc… ammunitions, we are sure to retrieve the A-10 in smoky wreckages, and US pilots as chopped steak.”

          Sorry, but that is simply wrong. A-10 was not sent from the start, and USAF put off sending it as long as possible. So far it has proven highly survivable against MANPADS and other ISILs air defences while supporting Peshmerga at low altitude. What you are saying is just USAFs excuse.

          “The A-10 is supposed to be immunized against 23 mm caliber, as far as possible not much shots.”

          Enough shots to get out of the way.

          “and I recall when you talked about the pitiable results of air campaign against Serbia.”

          Which was in good part caused by the refusal to let aircraft fly below 10.000 ft or so.

          “If the A-10 was the miracle weapon, every country in the world will buy it, at first Israel, but this is not the case.”

          Again, wrong. You have to understand politics as it has huge impact on weapons procurement, far greater than any practicality / effectiveness issues. First, I do not think that US ever cleared A-10 for export. Second, air forces hate having single-purpose CAS aircraft, as it reminds them of the fact that their entire purpose is actually to support the Army… which hardly justifies existence of independent air forces. Third, multirole fighters are more expensive, and are so far better for interservice budget wars, as well as for the defense industry.

          Like

  9. Chris said

    Air and naval power are the means to an end, not an end into itself.

    That has been forgotten though in the interservice rivalries.

    Like

  10. MrBsct said

    IRST the primary sensor of modern aircraft? HAHAHAHAHAHA. What a fucking joke Picard.

    Yeah AESA is instantly detected by RWR and jammed easily.

    Like

  11. Foxhound said

    Thx Picard for your articles, and interventions in comments.

    Regards.

    Like

  12. Very interesting article Picard.

    I would like to go further.
    Sure IRST make the radar less important than it used to be.
    But more than that, i would say that the new sensors linked together, plus data link in general change a lot the way we used to see fighters performances by the past.

    For my explanation, i take the Rafale as an example cause it’s a plane a know.

    The passive devices listed bellow can detect, locate, lock, a give a fire solution:

    – TV (part of OSF) + a short laser mesure for distance (ok, it’s not passive…). Range up to 100km (depends on the target and its angle).
    – DDM ng (Missile Departure Detector new generation): The image it creates is like a black and white picture made with a fish eye lens. The picture of the situation is so precise in angle and distance that it is not only used for missile departure now, but for firing solution. Close to the F-35’s EODAS (Electro Optical Distributed Aperture System), in fact.
    – Link 16: A plane can receive a fire solution from another fighter.
    – SPECTRA (Self Defence Suite): Totaly passive. it can be used to find and lock a target.

    In my opinion, more than IRST alone, it’s the overall of all these devices, and their addition, the way we use them, the timming, wich plane of a wing using a device or another one, that make the radar being part of it now, and not only the principal way of engaging a target.

    These types of plane (like the Rafale), using data fusion created from all these devices, change totaly the way we used to see aerial combat.

    Now, to have a clear situation awardness and a firing solution, no need to iluminate the whole combat aera with a powerfull radar. And by doing that being spoted.

    The tactical options offered by these “new” devices and the AESA radar are very large and some, still to be discovered, i think.

    In a way, i would say that we can’t appreciate anymore a fighter by its pure performances on paper.
    It’s much more subtile.
    We have to consider the devices used, their balance onboard the fighter, inside the tactics used.

    In old time, it was said” first to see, first to shoot”.
    It’s a sort of joke, but we can add now, “first to shoot, first to be seen”…

    Liked by 1 person

    • picard578 said

      Agreed. I think that more focus should be placed on developing tactics centered around passive detection.

      Like

    • Andrei said

      @syntaxerror9

      May I ask how you know so much about the Rafale? There are a lot o information you have, regarding mostly sensor performance and so fort, that I cannot find any where on the net. Do you have links to any articles or documents? I ask because I would like to have more hard data on the performance of SPECTRA and Rafale’s DDM-NG. I mean from the deletion of the IRST component on the OSF on the F3 standard one would be led to believe that the DDM-NG offers similar detection ranges and thus makes the IR component of the OSF superfluous. Can you please give more details?

      Like

      • Most of i know about the Rafale comes from french website.

        I’m learning about the Rafale for years now…

        Here a link about DDM ng (in french) where you’ll find in particular, a picture of what the DDM ng can see:
        http://www.portail-aviation.com/2014/02/exclusif-le-ddm-ng-un-detecteur-de_8513.html

        Here a link where all Rafales aspects are shown (in french):
        http://rafalefan.e-monsite.com/pages/dossier-rafale-avionique/genese.html

        Yes, the IRST coponent should be deleted for the next Rafale F3R.
        From what i know, there are two reasons for that:

        1/The DDM ng can scan all around and target planes, missiles long after launch, ground targets,..
        And it makes the job better than the IRST used to do, due to the quality of the image it creates and its very low level of false alerts.
        From what i understand the range of the DDM ng is similar if not better than the IRST’s Rafale and less depending of the target’s aspect…

        Recently a MICA shoot “over the shoulder” (shoot at six o’clock) has been performed using only SPECTRA (totaly passive mod). A picture of the SITAC (tactical situation) of that shoot can be find on the net.
        DDM ng is part of SPECTRA, and we can argue that most of the job for the lock has been made by the DDM ng.

        2/The new TV coponent of the OSF for the Rafale F3R will have a wider wavelenght.
        A point of its spectrum should be very close to IR.

        For SPECTRA, very few informations because it’s the most precious and secret thing onboard the Rafale.

        SPECTRA is:
        A big computer + data fusion + DDM ng + jammers + the AESA radar using its jamming properties + electro magnetic sensors + automatic flares and chafts dispenser + a constant evolutive “library” of electromagnetic threats (ground radars, airborne radars,…) + tactical situation display giving avoidances routes proposals and threats positions + all devices, present or future, that could be used for self defence of the plane.
        SPECTRA is the combination of all of that.
        It is said that SPECTRA could be close or more…, to be able to perform active cancellation.

        Like

      • picard578 said

        IR sensor was deleted because they are waiting for a new sensor; old was technologically obsolete and was not in production any more.

        Like

  13. The tactical situation inside the Rafale showing the passive shoot at 6 o’clock:

    Like

  14. Yes Picard, Th IR sensor was obsolete.
    But without the two reasons i gave, it would have stay and/or would have been upgraded.

    Like

  15. No from what i know.
    There will not have any IR component on future OSF.
    And if i relember well, OSF of some of the latest Rafale, have no IR already.
    They queep the shape but it’s an empty space and its equivalent weight.

    Like

  16. From what i know, there will have no more IR in future OSF.
    I could be wrong, but some of the latest Rafale have a dummy IR on their OSF already.
    Don’t understand your second comment because you wrote the opposite just before?

    Like

  17. Sorry for that mess with these two and now three posts!
    Anyway IR or not, it’s not important.
    DDM ng makes the job.

    Like

    • Andrei said

      Thank you for your quick answer and the links! While the information on the first link is a lot of suposition it is supported by logic and available information. And Unlike the US DoD and Lockheed Martin which for marketing and especially public support reasons give all kinds of detail regarding the capabilities of the F-35 the AdA dose not have any reason to disclose the all the capacities of the Rafale to the general public. On the contrary keeping secret the information that SPECTRA is capable of using the DDM-NG as a spherical IRST, dose more good as the potential enemies can be surprised.

      Like

  18. Dassault and ministry of defence don’t need to comunicate much about the Rafale’s performances.
    They beleive is their tool.

    Do they have to use lobbying to insure politics and tax payers to spend more and more money in their program as LM does with the F-35? No.

    Do they have to speak to general public of 5th generation, of the a plane that doesn’t need to dogfight, of an invisible plane,…and so on? No.

    What you can observe with F-35’s communication is only technicals allegations, lobying and not a single operational fact in its favor.
    The only real, objectives facts about F-35 are technicals problems , cost increases, low operational performances for now, and program delays.
    Let’s talk of that fighter plane when it is one!

    Rafale has just to desmontrate its qualities to potentiel customers and in real operations.
    And that’s what is doing for years now by winning all technicals, operationals and cost efectiveness compétitions is was involved in, and by doing the job well in everywhere it had to fight.

    Liked by 1 person

    • Andrei said

      “What you can observe with F-35’s communication is only technicals allegations, lobying and not a single operational fact in its favor.
      The only real, objectives facts about F-35 are technicals problems , cost increases, low operational performances for now, and program delays.
      Let’s talk of that fighter plane when it is one!”

      I agree with what you say except the last phrase. I don’t think the F-35 will be a fighter? Maybe a Bomber.

      “Rafale has just to desmontrate its qualities to potentiel customers and in real operations.
      And that’s what is doing for years now by winning all technicals, operationals and cost efectiveness compétitions is was involved in, and by doing the job well in everywhere it had to fight.”

      I agree with you. Problem is that F-35 fan-boys dismiss this and say it’s obsolete and then hit me over the head with some “technical allegations” of what the F-35 will supposedly do someday. When that happens I want to have a link to send them and tell them: “See the Rafale is already doing that” 😀

      Like

  19. American indian proverb:
    “Who talk loud, say nothing.”

    Like

  20. Chris said

    Totally off-topic, but has everyone read about the concurrency issues with the new Ford class of aircraft carrier:

    http://foxtrotalpha.jalopnik.com/the-pentagons-concurrency-myth-is-now-available-in-supe-1689810660

    Apparently that too had a very high degree of problems.

    Like

    • picard578 said

      Concurrency is specifically designed to increase the costs, not reduce them.

      Like

    • Chris said

      The article argues that it will be a bigger problem right now because unlike aircraft which are bought in many copies, only a handful of aircraft carriers are ever built. Ships by nature are like that. Of course the US could probably build a couple of dozen smaller aircraft carriers, but even then, I suppose with ships there’s less margin for error.

      The other nugget is that apparently the Gerald R. Ford will be a very non-standard unit.

      But yes, it does look like concurrency will do little save feed the defense industry.

      Like

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