While a few know about the F-15J fitted with an internal IRST system, what is lesser known is that the same IRST system was put into an external pod for continued use and testing on other airframes.
Overview:
The (Unnamed) IRST device started it’s life from research as early as 2002, however it wasn’t until the early 2010s when it came into a functional existence. While originally intended to be internally mounted, as it was on 12-8928, they also tested an external configuration of a 500 gallon fuel tank for testing on other airframes without adverse affects on other avionics systems. It features a dual band focal plane array seeker, of unknown resolution. And is fully capable for the slaving of weapons via ESM. While it does not appear to have made serial production, given the lack of a name asides from “F-15J IRST Device”, the existing ones have been fitted on multiple airframes. It has extremely long range and a large field of view, it’s scan azimuth is roughly 100 degrees, with elevation limits of roughly -25/+70 degrees. It’s detection range is claimed to be about equal to the AN/AAS-42 (185 kilometers). It has full offensive and defensive sensor fusion.
Key Features:
Multiple Scan Modes
The device has multiple scan modes, it’s main one being a hybrid TWS which works in conjunction with the host aircraft’s radar, with the IRST scanning over large areas, with the radar then locking and tracking detected objects by it. This comes in wide and narrow scan variants. It additionally has boresight and vertical targeting modes. Additionally, due to its information being part of ESM, it includes IFF capabilities.
Dual Band Focal Plane Array
The seeker is a dual band (3-5µm and 10µm) focal plane array seeker using quantum dot infrared photodetectors, with approximately twice the seeker elements as the Rafale’s PIRATE system. It has NCTR capabilities, including the ability to detect missiles. It has range and direction finding capabilities, as well as the ability to detect error rate in identification and direction finding functions, including for the rejection of background clutter/active interference. Area of detection is as prior stated, roughly 100 degrees azimuth and -25/+70 degrees vertical, with a detection range of approximately 185km.
Maws Functionality
While it is not clear if the internal variant had MAWS functionality, the external pod appears to have so, with specific attention being brought to its ability to track and identify missile types, as well as the pod appearing to have a side facing sensor. (The rear of the F-15J(M) should already be covered by a radar based approach warning sensor, however it’s not modeled in game).
Electronic Support Measures
The IRST has full ESM/ECM (sensor fusion functionality). This means it works in conjunction with the radar to provide a more accurate lock by the combining of signals to decrease error rate, as well as to detect when countermeasures are in use, so when the radar loses accuracy due to interference the IRST takes priority, or vice versa. It works for slaving anything that can be slaved by the radar lock. Specifically for the AAM-4, it can actually be used solely without the radar even being on, as the AAM-4 uses the J/ARG-1 command transceiver, and not sidelobe attenuation, so it does not need the radar to be active for it’s datalink to be active (which, due to it’s frequency modulation method, can not be detected by almost any RWR in game). Additionally, due to it having error rate detection, it’s fully functional with the AAM-4’s terminal datalink connectivity, allowing for it to provide targeting information even when the AAM-4 has a terminal lock, assuming the AAM-4 detects its own seeker as having a larger margin of error, or by combining the signals in some non-binary amount relative to each’s error rate.
HMD Functionality
In addition to it’s other scan modes, the IRST device is capable of being slaved to the HMD for high off-boresight locks, this is particularly important for the AAM-5, as when fired in off-boresight mode it relies on inertial guidance, so by providing an accurate range and heading for the target it greatly improves the missile’s chance to hit versus firing inertially from HMD heading alone.
Both the F-15J and F-15J(M) in game could get it, as it requires the reprogramed OFP to function, which it received in IRAN with the PSP version of the radar. Since our F-15J in game is already a post IRAN model it can technically get it, although it was not used on Pre-MSIP ones in real life.
- Yes
- No
Sources:
平成１４年度政策評価書（事前の事業評価）１４年６月～８月
平成２４年度 政策評価書（事後の事業評価）平成２５年１月～平成２５年３月
４－２４－２００９－０３０Ａ－ＦＸ－０００５ 防衛省技術研究本部試作仕様書 平成２４年１１月９日
TRDI 60th Anniversary Research Summery book.
Research and Prototype of Long-Distance Detection Sensor System (Part 2) 3, 2750GCRID/022S85-014 January 17, 2013, Fujitsu Limited