Offsetting Radar Range Deficiency in Air Combat

(Revised July 2, 2016. See bottom of the page for the complete revision history)

A MIG-21 Bison of the Indian Air Force. Photo courtesy of aztonyx thru Flickr

In my previous blog, "The FA-50 Golden Eagle versus the SU-30MKK/MK2 Flanker-G", I indicated how the FA-50 Golden Eagle (or Geagle) was vastly deficient in terms of air to air detection range when compared to China's top fighter aircraft, the SU-30MKK/MK2. The Geagle's EL/M-2032 radar is small, light and relatively cheap, it provides very high ground mapping capability and long range detection and tracking of ships,^[1] but it doesn't have a lot of range in terms of air to air detection range, at least compared to radars like the SU-30MKK's Zhuk-MSE.

But as I said then, there are ways to offset this disadvantage, and the blueprint in doing so lies in what the Indian Air Force's (IAF) has done with their MIG-21 Bison aircraft enabling it to be effective even against aircraft like the United States Air Force's (USAF) F-15C Eagle as proven in war exercises like the "Cope India" and "Red Flag" exercises. 

A summary of the Bison's exploits in the Cope India exercise is available in the "Sources" section,^[2] and the Bison's performance at Red Flag was detailed in a lecture captured on video conducted by Colonel Terence Fornof, an F-15 pilot and the then Director of the Requirements and Testing office at the USAF Warfare Center at Nellis AFB in Nevada.^[3]

'Aircraft Background'
The MIG-21 was made by the then Soviet Union's Mikoyan-Gurevich Design Bureau and was first introduced way back in 1959. The "Bison" version is an improved version introduced in the late 1990s with a better engine and radar, and fitted with advanced avionics and weapons like Multi-Function Displays (MFDs), Helmet Mounted Sight (HMS), Tactical Data Link (TDL) and R-73 High Off-Boresight missiles. In its current configuration, the Bison is described as a Light Combat Aircraft (LCA) and India has around 125 of these in service.^[4] [5]

The Bison is very similar to the Geagle, with the Geagle slightly heavier (6,450 kg empty weight versus the Bison's 5,339 kg empty weight) and the same Thust to Weight Ratio with full internal fuel (0.93-0.96). Their radars even have similar ranges against targets with 5 m^2 Radar Cross Sections at around 46-50 km.^[6]

The F-15 Eagle was made by the United States of America's McDonnell Douglas Corporation and first entered service with the USAF in 1976. The "C" version is an improved version introduced in the early 1980s giving it better radar, engines, avionics and able to carry more fuel and weapons. It is described as an all-weather, Air Superiority, Air Defense Fighter aircraft of which the USAF currently has 254 in service.^[7] [8]

The SU-27 Flanker aircraft (which the SU-30MKK/MK2 Flanker-G aircraft was based on) was actually designed to at least match the F-15 Eagle, and like the Eagle it is large, carries a powerful radar and armed with long range missiles enabling it to detect and launch missiles from afar. Both the Flanker and Eagle are also excellent dogfighters, effectively covering both Beyond Visual Range (BVR) and Within Visual Range (WVR) of the air combat envelope.

As we can see from above, the Bison-Eagle confrontation is very similar to a Geagle-Flanker G possible confrontation, and it should be a prime interest for us on how the Bison was able to offset the Eagles' advantages in the Cope India and Red Flag Exercises.

'Tactical Data Link'
The Bison with its short range radar in the air to air mode could not possibly hope to compete one on one with the Eagle's radar, hence it did the next best thing: It used more powerful radar assets to get targetting information on the Eagle as relayed thru its TDL. The Bison used two main sources during the exercise: Either Airborne Early Warning (AEW) aircraft, and/or SU-30MK aircraft. Because of this the Bison was able to offset its weakness in terms of radar capability by using better "eyes" whenever it was available.^[2] [3]

The Geagle does have TDL capability, hence it can do what the Bison did in terms of linking up with better radars to offset its radar disadvantage against the Flanker-Gs. The Philippines does not have any AEW assets at the moment, but the beauty of the TDL system is that it can use any other asset to share information from regardless of platform type. For example, the two brand new Frigates that the Philippine Navy (PN) is buying are specified to have TDL capability, and thus could be used by the Geagles to get targeting information.

USAF F-15C Eagle Firing a Sparrow Missile. Photo courtesy of Wikipedia Commons

The Philippine Air Force (PAF) also reportedly currently have a couple of semi-mobile AN/TPS-32^[9] and AN/TPS-79^[10] ground based radars. I don't know if these have data link capability (probably not), but if not they can be upgraded to have so using interfaces like RSI's Universal Radar Interface Unit^[11] so they all can be used by the Geagles as additional radar assets.

Of course the PAF will need a lot more data-linked and networked radars to make this whole thing work, and there are plans to acquire more in the coming years. They might want to consider getting a couple of AEW aircraft as well to make their air defense system a lot more effective. The only disadvantage of using other radar assets is that the Geagles will have to stick close to them in order for it to continue using their radar capability. It cannot stray far from them, and if something happens to those assets then the Geagle will effectively lose that capability.

'ECM Equipment'
The other thing that the Bisons used to offset the Eagle's radar advantage is thru the use of Electronic Counter Measure (ECM) or "jamming" equipment. These jammers degraded the Eagles radar capability to the point that the Eagles were forced to engage the Bisons in WVR combat where the Bisons had much better chances of surviving and even winning against the Eagles.^[3] The Jamming equipment the Bisons used were reportedly made by Israel, and were probably placed on the dorsal "hump" behind the cockpit allocated for additional equipment and not on pylons as the Bisons only has a limited number of these at 5.

The ECM jammers probably worked in this way: First is that degraded the Eagle's ability to detect them from long range. So for example if the Eagle was able to detect the Bisons at 100 km, it degraded this number to, say, around 50 km. And then even if the Eagles were finally able to detect the Bisons, it degraded its Tracking Range also so it is not able to get reliable targetting information for its BVR missiles. Typical tracking range is around 83% of the detection range,^[12] but the jammers could've interfered with this enough to bring down the range even further.

Now if the Eagles were only able to finally track the Bisons at around 10 km, then that is within the range of WVR missiles already, and coupled with the fast closing rates of both aircraft and other additional countermeasures, then that would've forced the Eagles to go into the merge and go into a dogfight. Note that Col. Fornof also said that the F-15C Eagles themselves used jamming equipment to negate the SU-30MK's radar capability during their encounters and force the SU-30MKs into a dogfight during the Red Flag exercises.^[3]

The PAF currently has no known plans to get ECM Pods for the Geagles, but perhaps this is something they should seriously consider. We only have limited assets, hence anything that will help keep the Geagles competitive against its opponents should be considered as much as possible.

'Tactics and DFRM'
Additional countermeasures that the Geagle can use to help offset its radar advantage would be thru TACTICS. One is that it can take advantage of the fact that an aircraft radar's Look Down Range is lower than its look up range due to ground clutter. For example, the SU-30MKK's maximum look up range for a 5 m^2 Radar Cross Section (RCS) target is 190 km, but its look down range is lower at only 140 km for the same target (estimated only),^[13] hence the Geagle can stay low and gain a couple of dozen more kilometers of undetected range before it is detected.

The disadvantage of this is that the Geagles will be coming into a dogfight at a "lower energy state" or lower altitude than the Flanker-G, but a good compromise would be for it to start climbing into its opponents as soon as they get to within the opponent's tracking range to gain some altitude and Potential Energy (PE). Other tactics would be thru the use of evasive maneuvers and Infra-Red/Chaff Decoys once its opponents are able to track it.

And yet another aid the Geagle could use as insurance against BVR missiles is the use of another type of jamming equipment called Digital Radio Frequency Memory (DRFM). This is specifically used for defense against missiles with Active-Seeking Radar Guidance, which is typical in most of the current BVR missiles like the AIM-120 Advanced Medium Range Air to Air Missile (AMRAAM). 

DRFM is quite insidious as it works by DECEIVING the missiles. What it does is it analyzes the signals used by the attacking missile's guidance system, then provides false radar returns to the missile, and in the process making the missiles miss their target.^[14] This technology is still untested as of now, but it is one avenue worth looking into. The "Super Flankers" and Eurofighters are using this technology to help defend it against missiles with active-seekers.

'Parting Shot'
To summarize, there are a number of ways the Geagle can offset the Flanker-G's advantage, and these are thru:
- Use of better radar assets thru Data Link;
- Use of jamming equipment;
- Tactics such as staying low to make it harder for the opponent to detect it
- Use Chaff and evasive maneuvers when within tracking range
- Use of DRFM technology

The IAF MIG-21 Bisons has already proven that using some of these technologies enabled it to avoid being shot at with BVR weapons and force the USAF F-15C Eagles to WVR combat in not just one but a couple of war exercises, and one hopes that the Geagle will be able to do more or less the same against China's Flanker-Gs.

Two SU-30MK2s of the Venezuelan Air Force. Photo courtesy of Big Bosstt thru Flickr

SOURCES:

[1] Multimode Airborne Fire Control Radar ELM-2032, 

https://web.archive.org/web/20160421193601/http://www.iai.co.il/Sip_Storage//FILES/0/38030.pdf

[2] Cope India 2004 - An Analysis, 

https://web.archive.org/web/20160304054338/http://www.indiadefence.com/COPE.htm

[3] Red Flag 2008-4 : Lecture by USAF Col. Terrence Fornof, 

https://web.archive.org/web/20141223224129/http://vayu-sena.indianmilitaryhistory.org/exercise-red-flag-su-30mki-comparison-fornof.shtml

[4] Mikoyan-Gurevich MiG-21 variants - Upgrade Programs, 

https://web.archive.org/web/20160701200755/https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21_variants

[5] Mikoyan-Gurevich MiG-21 operators - India, 

https://web.archive.org/web/20131208202012/http://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21_operators

[6] Kopyo Radar,
https://web.archive.org/web/20160315150715/http://toad-design.com/migalley/index.php/jet-aircraft/mig21/mig21-kopyo-radar/

[7] McDonnell Douglas F-15 Eagle - The Ultimate MiG-Killer, 

https://web.archive.org/web/20160318195433/http://ausairpower.net/Profile-F-15A-D.html

[8] List of F-15 Operators, 

https://web.archive.org/web/20150711161248/https://en.wikipedia.org/wiki/List_of_F-15_operators

[9] Philippines – New Radar Plans, 

https://web.archive.org/web/20131014015457/http://chainhomehigh.wordpress.com/2013/09/25/philippines-new-radar-plans/

[10] 4 units of AN/TPS-79 Multi-Mission Surveillance Radar (MMSR) 1 has already been delivered., 

https://www.facebook.com/afpmodernizationfanpage/posts/575477592474955

[11] Universal Radar Interface Unit, 

https://web.archive.org/web/20160317002351/http://redondosystems.com/uriu.html

[12] Which Fighter Plane is the No:1 in the Indian Subcontinent in the BVR(Beyond Visual Range) arena?, 

https://web.archive.org/web/20160105112629/http://www.angelfire.com/falcon/fighterplanes/texts/articles/bestfighter.html

[13] Su-30mki, Mkm R Better Than Mkk, 

http://forum.pakistanidefence.com/index.php?showtopic=22089&#entry303648

[14] Digital radio frequency memory, 

https://web.archive.org/web/20160618164307/https://en.wikipedia.org/wiki/Digital_radio_frequency_memory


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Revision History:
(0) October 31, 2013: Blog originally posted
(1) July 2, 2016: Updated footnotes format to the latest standard; Started using “The Wayback Machine” to archive the links;

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