Atlas Elektronik AVtive Towed Array Sonar (ACTAS) system is a sonar sensor towed behind the vessel, capable of detecting submarines at a distance of 60 km or more. Photo" Atlas Elektronik
Atlas Elektronik AVtive Towed Array Sonar (ACTAS) system is a sonar sensor towed behind the vessel, capable of detecting submarines at a distance in excess of 60 km. Photo: Atlas Elektronik

Atlas Elektronik and the Indian Ministry of Defense have signed a contract for the delivery of six active towed array sonar systems (ACTAS) for the Indian Navy. The total contract volume is approximately 40 million Euros. Delivery of the first system is planned for 2016.

The six systems would equip three Talwar-class frigates and three Delhi-class destroyers, providing them with the capability to detect enemy submarines. Both classes of vessels have been prepared in advance to accept the German system. Atlas was selected as the preferred contractor for the system in October 2013 with formal award negotiated since.

Following the Indian selection in October last year the Thai Navy has also selected ACTAS, along with Atlas’ bow sonar (ASO) as the primary ASW sensors for a Korean built frigate to be delivered to the Royal Thai Navy in 2016.

[ismember]Together, the two systems offer active and passive sonars for the detection, tracking and classification of underwater vehicles, such as submarines, torpedoes and unmanned underwater vehicles (UUV). As with the six Indian systems, the Thai sonars will be delivered early in 2016.

The ASO bow sonar operates in the frequency range between 6 and 9 kHz and provides a surveillance radius of up to 15 kilometres around the ship. This makes it most suitable for the self-protection of the ship. ACTAS has the capability to locate and track submerged submarines or locate surface vessels, which permits reconnaissance of both submarines and ships in the same sonar search area. These sonars are able to detect and classify small speedboats, divers or floating obstacles, such as containers or tethered mines.

The towed array sonar ACTAS operates in the low-frequency range from about 2 kHz and permits observation of the sea space at ranges considerably above 60 kilometres, depending on the propagation conditions of the water. The  ACTAS  towed array sonar operates in the low-frequency range (2Khz) and permits observation of the sea space at ranges in excess of 60 kilometers, depending on the sound propagation conditions of the water.

The  towed array sonar  extends the surface warships operational range beyond the range of periscope detecting radar or submarine launched torpedoes, thus providing the surface warship an operational advantage in the ASW battle.[/ismember]

Originally the Indian MOD planned to source towed sonar work domestically, but after waiting for almost a decade for the DRDO subsidiary NPOL to deliver a locally developed low-frequency active towed-array sonar, the Navy awarded the contract to Atlas, to supply ultra low-frequency active/passive towed-array sonar systems. In the near term the sonars will eventually equip 30 surface vessels with the systems. [ismember]The vessels to receive the ACTAS include three Project 17 ‘Shivalik’ class Frigates, three Project 15A ‘Kolkata’ class destroyers, four Project 28 Kamorta class ASW corvettes and the three upgraded Project 1241PE ASW corvettes (Russian built ‘Tarantul’).

Future surface vessels receiving the system include six Project 1135.6 ‘Talwar’ class Frigates which are vessels receiving the currently contracted systems. The systems are also likely to equip the seven Project 17A frigates and four Project 15B ‘Bangalore’ class missile destroyers – the first ship of each class is currently under construction.[/ismember]

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