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Details of the Pakistan Navy’s Agosta 90B Submarine Upgrade Program

In June 2016 the Pakistan Navy (PN) signed a $350 million US contract with Turkey’s Savunma Teknolojileri Mühendislik A.Ş. (STM) to upgrade its three Agosta 90B air-independent propulsion (AIP) submarines.[1] As per STM, the first upgraded submarine – PNS Khalid — is scheduled for delivery in 45 months. This would place its delivery in 2020. The remaining two are to be delivered within 12 months of the preceding ship.[2]

Currently, the PN has signed onto upgrading two of the three submarines, with the contract for the second – PNS Saad – being signed in February 2018.[3] STM will implement the upgrade at Karachi Shipyards and Engineering Works (KSEW). The contract for the third ship – PNS Hamza – should follow in the short-term.

Labelled a ‘Mid-Life-Update’, the upgrade is primarily concentrated in changing the submarine’s electronic subsystems, such as its sonar, radar, combat management system (CMS), electronic intelligence (ELINT) or passive sensors and the like. Described in detail below, these subsystems are being acquired from first, second and third-party sources, with the latter including South Africa, the UK and Germany.

Based on verifiable and open-source information, the subsystems described below will be integrated into the Agosta 90B. However, while an electronics upgrade, it must be noted that by pairing the subsystems below the PN should be able to achieve a credible level of sensor fusion in the Agosta 90B.

Hensoldt Optronics South Africa OMS-200 Optronic Mast and SERO 250 Periscope

In October 2016, STM awarded Hensoldt Optronics South Africa (HOSA) a contract to supply its OMS 200 optronic mast and SERO 250 periscope.[4] The OMS 200 comprises of a high-definition television camera, a laser rangefinder and shortwave infrared (SWIR) camera.[5] It can be integrated to the submarine’s combat management system (CMS) such that it can be controlled from CMS consoles. Pakistan will pair the OMS 200 with the HOSA SERO 250 periscope and, like the OMS 200, can be integrated to the ship’s CMS.[6]

Integrating the OMS 200 and SERO 250 to the Agosta 90B will result in the following benefits. First, a boost to the Agosta 90B’s intelligence, surveillance and reconnaissance (ISR) capabilities by giving it the capacity to capture high-quality visual assets (e.g. video, thermal imagery, etc). Second, automation thanks to the ability to control these systems via CMS) which will offer submarine commanders additional flexibility.

Kelvin Hughes SharpEye Pulse-Doppler Radar

In February 2017, Kelvin Hughes of the UK – and one of Hensoldt’s companies – was contracted by STM to supply its SharpEye I-band pulse-Doppler radar for the Agosta 90B.[7] In November 2017, STM awarded Kelvin Hughes the contract to supply the radar for the second submarine, PNS Saad.[8]

The SharpEye can be used for both navigational support and situational awareness. In terms of the later, it will enable the Agosta 90B to find targets as small as 0.5m2 at “several nautical miles.”[9] It is also capable of clutter removal and a high level of reliability thanks to solid state electronics.[10] Kelvin Hughes states that the radar uses “GaN (Gallium Nitride) power transistor technology”.[11]

Aselsan ARES-2SC Electronic Intelligence (ELINT) and Electronic Support Measures (ESM)

In November 2016, STM selected Aselsan’s ARES-2SC/NS electronic support measures (ESM) suite for use on Pakistan’s ships.[12] The ARES-2SC/NS was designed for the Turkish Navy’s forthcoming Type 214s. The ARES-2SC/NS comprises of passive sensors designed to identify radar emissions, including those from low-probability-of-intercept (LPI) radars.[13] It is basically an electronic intelligence (ELINT) system.

According to Aselsan, the ARES-2SC/NS’ offers 360° azimuth coverage. It displays radar emission sources in “near-real time” and “on a continuous basis.”[14] Like the OMS-200 and SharpEye, the ARES-2SC/NS’ feed can be viewed from the ship’s CMS.[15] In addition, the ARES-2SC/NS can also register the emissions it picks up, potentially indicating that it can add (new electro-magnetic emission data) to a threat library.[16]

Besides providing the Agosta 90B with situational awareness of nearby surface vessels equipped with air or surface surveillance radars, the submarine could potentially operate as an intelligence, surveillance and reconnaissance (ISR) asset. Granted, the Agosta 90B cannot relay that information to other assets such as surface vessels or aircrafts while being submerged. However, this can be a factor in peacetime by enabling the Agosta 90B to monitor naval activity and, in turn, keep fast-reaction assets (e.g. aircraft) up-to-date.

Atlas Elektronik ISUS-1000 Integrated Sensor Underwater System

STM has yet to officially announce a new sonar suite for the Agosta 90B. Currently, the Agosta 90B relies on the Thales TSM 223. However, it would be surprising if that is left when every other system is removed.

The German electronics supplier Atlas Elektronik revealed – through its own official product information – that Pakistan is a customer of its ISUS 100 Integrated Sensor Underwater System.[17] Atlas Elektronik markets the ISUS 100 as “the new generation of sonar sensors for operation [in] complex littoral waters.” It includes an expanded flank array sonar (EFAS), extended towed array sonar (ETAS), enhanced cylindrical array sonar (ECAS) and multi-purpose active sonar (FLAS).[18]

Interestingly, Atlas Elektronik states that the ISUS 100 can be integrated with commercially off-the-shelf (COTS) systems.[19] This is relevant to the PN because it, evidently, is doing exactly that by having STM pick a range of items from multiple vendors. On that vein, the end-user can (optionally) integrate the ISUS 100 with soft-kill and hard-kill countermeasures (to defend the submarine from incoming torpedoes).[20] While no such equipment has been announced for the PN’s ships, it is doable.

That aside, it is not surprising that the Agosta 90B would use the ISUS 100; the PN’s main heavyweight anti-submarine warfare torpedo is the Atlas Elektronik DM2A4 (i.e. SeaHake Mod. 4).

Havelsan Sonar Integrated Submarine Command and Control System (SEDA)

The Turkish defence electronics supplier Havelsan is supplying two major subsystems for the program: (1) the “Integrated Underwater Command-and-Control System” and (2) “Submarine Information Distribution System” (SEDA).[21] Havelsan will integrate Hensoldt, Kelvin Hughes, Aselsan and Atlas Elektronik’s systems to its own, thus essentially tying the Agosta 90B’s various sensors and fire control systems into one suite.[22]

Pakistan’s Upgraded Agosta 90B Submarines are not to be Underestimated

The PN’s Agosta 90Bs are AIP-equipped ships. This means that they are capable of operating submerged without snorkeling for extended periods of times. While the exact capability has not been disclosed, it is likely to be enough to sustain a short-term conflict. However, the significant electronic upgrades will bring the Agosta 90B up-to-par with its contemporary counterparts, keeping a relevant platform for decades.

These submarines will have the subsystems necessary for sensor fusion, though a sensor fusion engine is necessary to sensibly present the data to the crew. This is likely being done by Turkey, which would likely want one of its own to both complete its indigenization drive and to guarantee capability in its own ships.

Yes, to use its non-acoustic sensors (e.g. ARES-2SC/NS) the Agosta 90B cannot be submerged, but this can be peacetime ISR asset for monitoring nearby naval activity. Likewise, the Agosta 90B could use its long-range sensor data – and sensor feeds from other platforms – to undertake anti-ship missiles with its long-range anti-ship cruising missiles (ASCM) (albeit, by launching them while surfaced). That said, the ISUS 100 is the standard for anti-submarine warfare (ASW) operations, especially with the DM2A4 torpedo.

Can Pakistan Apply the Same Subsystems to the Hangor (II)?

The Pakistan Navy has eight Hangor (II) AIP submarines on order from China. Four of these will be built at Karachi Shipyard & Engineering Works (KSEW). The first four – which will be built in China – will be in the PN’s hands by 2023, but the KSEW-built ships will be delivered by 2028. Seeing how the Agosta 90B’s new subsystem suite will be effective, one might ask if the PN’s Hangor (II) could be configured along identical lines. It would certainly make sense as it would streamline the PN’s training, logistics and maintenance.

However, for it to happen several key factors must materialize. First, STM would need to have imparted sufficient expertise surrounding the integration work of these subsystems. Second, the likes of Hensoldt, Kelvin Hughes and Atlas Elektronik would need to approve of such work, especially on a Chinese platform. Third, the integration process itself must be feasible. Of these factors, the second one – i.e. the supplier’s discretion – will be the most important, but the rest are manageable.

Although the PN itself might opt for a more conservative route (i.e. getting the Hangor configured by the Chinese), the STM Agosta 90B upgrade program does set KSEW up to do the job itself.

Firstly, the Agosta 90B upgrade does not involve a first-party supplier. In choosing STM, the PN made the surprise move of not relying on the submarine’s original manufacturer, Naval Group (DCNS). In other words, the upgrade – i.e. the integration work – is independent of the submarine’s hull. Yes, knowledge of the hull must be in place to implement the upgrade (cue: the original transfer-of-technology deal with France), but neither STM or KSEW required Naval Group (much less Thales or SAGEM) in the process.

The lessons of this upgrade – combined with the transfer-of-technology gained from China – could be put to use with configuring the Hangor. This is more tenable with the submarines to be built at KSEW, but the Chinese could (in theory) deliver baseline hulls (i.e. without the acoustic and non-acoustic sensors) to the PN as well; this can be done for every Hangor from the onset. There is also precedent for this; Algeria and Thailand had configured their Chinese-built ships with Western equipment. In fact, Thailand equipped its Type 053-based Naresuan-class frigates with the Raytheon Evolved Sea Sparrow Missile (ESSM)![23]

Secondly, none of the subsystem suppliers have a geo-political problem with China. If anything, aversion to supplying the subsystems for use on the Hangor would stem from the concern of China accessing the intellectual property (IP) behind those designs and develop competing products. However, these original equipment manufacturers (OEM) can alleviate this concern by being present in Pakistan and collaborating with KSEW. Moreover, processes to protect IP should already exist seeing how some European companies, such as Safran Group and Airbus Helicopters, are already working with state-owned Chinese bureaus.[24]

[1] “Defense Industry Focuses on Quality and Quantity to Step-up Turkey’s Exports.” Defence Turkey. 30 September 2016. URL: (Last Accessed: 28 December 2017).

[2] Press Release. “STM Breaks New Ground in Pakistan.” STM. 22 June 2016. URL: (Last Accessed: 28 December 2017).

[3] STM. Twitter. 28 February 2018. URL: (Last Accessed: 01 October 2018).

[4] Richard Scott. “New periscope, optronic mast for Pakistan Agosta 90B submarines.” IHS Jane’s Navy International. 25 October 2016. URL: (Last Accessed: 28 December 2017).

[5] Official Product Information. Hensoldt. URL:

[6] Official Product Information. Hensoldt. URL:

[7] Press Release. “SharpEye for Pakistan Navy Submarine.” Kelvin Hughes. 21 February 2017. URL: (Last Accessed: 28 December 2017).

[8] Press Release. “SharpEye Radar for Pakistan Navy Submarine Upgrade.” 21 November 2017. URL:

[9] Official Product Information. “Naval and Coast Guard Radar Systems.” Kelvin Hughes. URL:

[10] Ibid.

[11] Ibid.

[12] “Submarine ESM Success.” Jane’s 360. 04 November 2016. URL: (Last Accessed: 28 December 2017).

[13] Official Product Information. “ASELSAN Radar Electronic Support Measure System for Submarine Platforms ARES-2SC/NS.” Aselsan. URL:

[14] Ibid.

[15] Ibid.

[16] Ibid.

[17] Official Product Information. “ISUS100 Integrated Sensor Underwater System.” Atlas Elektronik. URL: (Last Accessed: 12 October 2018).

[18] Ibid.

[19] Ibid.

[20] Ibid.

[21] “Havelsan Looks to the Future in War Management Systems.” MSI Turkish Defence Review. 27 December 2017. URL: (Last Accessed: 12 October 2018).

[22] “8th DSS Special Issue – Interview: HAVELSAN Command Control and Combat Systems Executive Vice President.” MSI Turkish Defence Review. 16 November 2017. URL: (Last Accessed: 12 October 2018).

[23] “Royal Thai Navy to Purchase Evolved SeaSparrow Missiles.” Naval Today. 15 January 2013. URL: (Last Accessed: 13 October 2018).

[24] Press Release. “China’s AC352 completes first flight with WZ16 engine.” Safran Group. 20 December 2016. URL: (Last Accessed: 13 October 2018).

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