Australian Collins-class submarines to receive multimillion-dollar sonar upgrade December 29, 2020, by Naida Hakirevic The Royal Australian Navy’s six Collins-class submarines will undergo significant upgrades to its sonar systems in Australia through a multi-million dollar contract with Thales Australia. The two contracts, worth around AU$23.7 million, are for the design and implementation of the Mine and Obstacle Avoidance System and the High Frequency Intercept Array for the submarine fleet. Minister for Defence, Senator the Hon Linda Reynolds CSC said both the Mine and Obstacle Avoidance System and High Frequency Intercept Array are important parts of the upgrades to the Collins sonar system.