Denmark’s Defence Acquisition and Logistics Organisation (DALO) has selected Atlas Elektronik to supply Low Frequency Active Towed Array Sonar (TAS) systems for retrofit to the Royal Danish Navy’s two Absalon-class frigates.
Announced through the EU’s TED tender portal on 28 February, the disclosure comes almost exactly one month after the Danish Ministry of Defence made its internal source selection decision.
In a statement also issued on 28 February, DALO said there would now be a 10-day ‘standstill period’ prior to beginning final contract negotiations. Atlas Elektronik, offering a solution based on its Active Towed Array Sonar (ACTAS) system, was selected ahead of a rival bid from Thales.
The anti-submarine warfare (ASW) upgrade of the two Absalon-class ships, HDMS Absalon and HDMS Esbern Snare, was first announced as part of Denmark’s 2018-2023 Defence Agreement. DALO commenced initial procurement activity back in late 2020, but the original competition was cancelled in June 2023 owing to changed requirements arising from Russia’s attack on Ukraine in February 2022. According to DALO, Russia’s aggression, and the subsequent admission of Finland and Sweden to NATO, “changed the geographical focus of a Danish ASW capability and tightened the operational requirements for the Armed Forces in order to be able to carry out ASW operations in the North Atlantic in cooperation with relevant allied nations”.
A revised tender for a Low Frequency Active TAS was subsequently issued by DALO. This outlined requirements for a dedicated blue water ASW solution “interoperable with existing Danish sonar systems in a bistatic and multistatic sonar environment, and [being] the primary sensors for future Torpedo Counter Measure systems”.
As well as requiring a system able to fit in a limited footprint on the stern of the Absalon design, the tender called for the TAS ‘wet end’ elements to be deployed and recovered without any mechanically connecting/disconnection by the deck handling crew. Associated deliverables include a shore based TAS simulator; training services; and an in-service support contract extending for up to 25 years.
The Danish Ministry of Defence on 29 January announced that a source selection had been agreed without disclosing the identity of the preferred bidder.
Defence minister Troels Lund Poulsen said in a statement:
“In light of the current foreign and security policy situation, I am pleased that a decision has now been made on who will supply [towed] sonar systems to our frigates, so that we can move forward with strengthening Denmark’s surveillance of submarine activity, including in the Arctic and the North Atlantic,”
DALO confirmed the selection of Atlas Elektronik on 28 February after a voluntary transparency notice was published on the EU TED website. Chief of the Navy, Rear Admiral Søren Kjeldsen, welcomed the decision. “With the choice of towing sonar, an important milestone has been reached in relation to building a Danish anti-submarine capability in the Absalon-class,” he said in a statement.
“The towing sonar is the primary sensor that will enable Danish frigates to participate in anti-submarine operations, including in the North Atlantic.”
Chief of the Royal Danish Navy, Rear Admiral Søren Kjeldsen
Rear Admiral Kjeldsen continued: “In addition to the selection and subsequent installation of the sonar, work continues to educate and train the personnel for this type of operation. In the coming years, this will take place in collaboration with allies who have many years of experience in the use of towing sonar, in order to give the Danish capacity the best possible conditions from the start.”
The ACTAS ‘wet end’ combines a high source level active transmitter (operating at a frequency range of 1.4-2.4 kHz) with a passive line array (covering frequencies between 50 Hz and 10 kHz). A triplet array (employing three hydrophones on a circular section of the array) is used to instantaneously resolve left/right bearing ambiguity.
Atlas Elektronik has previously supplied the ASO 94 medium-frequency hull-mounted sonars fitted to the two Absalon-class ships and the three Iver Huitfeldt-class frigates. DALO said that as well as meeting all operational requirements, the fact that Atlas Elektronik was already a supplier of other sonar equipment systems on Danish frigates would allow “a streamlining of ongoing operation and maintenance processes on the ships”. The acquisition of Low Frequency Active TAS systems for the Absalon-class frigates forms part of a wider effort to rebuild the Royal Danish Navy’s ASW capabilities. The other major part of this package is equipping Royal Danish Air Force-operated MH-60R helicopters with a sonics suite (dipping sonar and sonobuoy processing) and lightweight torpedoes.
