Ideas about the JF-17 Block-III’s AESA radar
September 18, 2019

Ideas about the JF-17 Block-III’s AESA radar

The provision of an active electronically-scanned array (AESA) radar is arguably the most significant system to be in place for the JF-17 Block-III, the forthcoming variant of the Thunder. We had already given a few thoughts about the JF-17 Block-III’s other subsystems – the helmet mounted display and sight (HMD/S) system, infrared search and track (IRST), and high off-boresight (HOBS) air-to-air missile (AAM).

These are all important systems, but there is a fundamental difference between them and an AESA radar; the AESA radar actually requires substantial integration work within the airframe. There is nothing to stop Pakistan Aeronautical Complex (PAC) from equipping the current JF-17 Block-I/II airframe with HMD/S, IRST and HOBS AAM. There is nothing inherent in any of these systems that require substantial changes to the airframe, even the IRST can be integrated as a podded solution.

On the other hand, an AESA radar, especially one that performs in terms of range and tracking, is heavy and it requires room for cooling and power (for its hundreds of transmit/receive modules or TRM). While we had earlier noted that the JF-17 Block-III’s airframe will not change as substantially as the Gripen E/F is to the Gripen C/D, it will still – by virtue of including an AESA radar – have some structural changes. How that takes shape has not officially been confirmed to the public.

Furthermore, the process will take time, and it is likely that the vendor will be involved in the process to some extent. This is an important point, but it will be discussed towards of the end of the article as it relates to the Pakistan Air Force (PAF)’s AESA radar options.

What does an AESA radar bring to the JF-17 Thunder? If anything, an AESA radar should bring substantial improvements in the JF-17’s electronic counter-countermeasures (ECCM) capabilities. In practical terms, this means the JF-17 would be more resistant to enemy electronic warfare (EW) jamming, which would come from digital radio frequency memory (DRFM)-based pods and integrated electronic countermeasure (ECM) suites. This is crucial. DRFM enables EW/ECM suites to record incoming enemy radar frequencies, and in turn, re-transmit them in an attempt to confuse the enemy radar.

Modern pulse-Doppler radars – such as the KLJ-7V2 on the JF-17 – transmit at one frequency with each pulse (but the radar will transmit a different frequency with each pulse, in an attempt to mitigate jamming). An AESA radar’s multiple TRMs can each transmit at different frequencies within a single pulse. Granted, a solid pulse-Doppler radar design could do well against enemy jamming attempts, especially if it comes from one or two sources (e.g. fighter aircraft); but if stuck in a dense EW environment that could include stand-off jamming aircraft, an AESA radar could provide assured protection.

Besides jamming, AESA radars also possess low-probability of intercept rates against enemy radar warning receivers (RWR). To what extent it impacts RWR in a real air warfare scenario is unclear, but any additional gap in an enemy’s ability to spot your aircraft is an important gain.

Overall, an AESA radar would be a pivotal gain, and in-exchange, it will be comparatively more expensive, not just in terms of funds, but time as well. Returning to an earlier point in this piece, i.e. the need for some structural changes to accommodate for the added weight and cooling systems. There is going to be a wait time in terms of incorporating the changes and running through the requisite tests. But with the F-16 route not looking good (see here for a full insight), the PAF may looking to streamline the process. In other words, the development work on the JF-17 could coincide with the selection of the vendor that will supply the AESA radar. All things considered, China is the most natural partner.

We had noted that Leonardo (formerly known as Finmeccanica) is an option on numerous occasions (here), and it may very well be, but it does not seem like they will be relied upon for the JF-17 Block-III. It is not just a matter of fitting a new radar, but actually adjusting the airframe to handle a new kind of radar. It would be more efficient to push the work to a single source, and when one has a vendor that can do airframe and radar work, why not take that route? Whatever added benefits the Leonardo Raven or Vixen has, are the costs of a more complex integration route worth it?

Little is known at this point, but the fact that the JF-17 Block-III will incorporate an AESA radar alongside HMD/S, HOBS AAM and potentially IRST cannot be understated. There is nothing to take away from the fact that the F-16 is a superb medium-weight design, but when looking at it from the lens of Pakistan’s reality, i.e. a situation where the best upgrades are withheld (due to cost and/or denial), the less appraised JF-17 Block-III emerges as the new qualitative driver.