Just some of the components of the US AN/BYG-1 combat system. Australia is already using it in the Collins and will use it in the future submarine. Japan is also interested in using more AN/BYG-1 parts for its own submarines. See this image much larger and readable here.
This diagram Australian Defence Force slide display (2015) explains the major elements of a Combat System.
The following are snippets of an article by Greg Sheridan, Foreign Editor for The Australian, February 11, 2016. I've hyperlinked and bolded some parts:
“Japan building Australian submarines is a match made in heaven
The $50 billion-plus program to replace our six Collins-class submarines, with up to 12 new subs, may have at its heart a dynamic which has barely featured in the discussion so far. That dynamic is a Japanese interest in acquiring the US combat system on the Collins, and the related [Mark 48] heavy torpedo.
…The Japanese Soryu subs...have a capable combat system but it is not as good as the US system. From the beginnings of the strategic discussions between Canberra and Tokyo, and at the highest levels of government and the bureaucracy, there have been quiet discussions that out of this process the Japanese could eventually acquire the US combat system for their own subs.
…The Americans also harbour the greatest concern about the ability of European defence companies to keep their technology secure from Chinese industrial espionage. Partly to reassure the Americans on this score, the Turnbull government is conducting a separate limited tender between two American companies, Lockheed Martin and Raytheon, as to who will be the combat system integrator on our new sub.
… given that the Soryu actually exists, whereas the German and French subs are completely new builds and exist so far only on paper, there is less technical and commercial risk with the Japanese as well…[see WHOLE ARTICLE]
The Australian is Australia’s most influential newspaper on national security issues – so it is impressive that it has substantial things to say about US and Japanese submarine combat systems. Combat systems are arcane to most newspapers.
The possibility of Japan adopting all of the elements of the US AN/BYG-1 combat system (not just some of them as at present) deepens the mutual benefits of a Japanese submarine sale to Australia. The extent of US influence on the submarine sale has been long covered by Submarine Matters here, here and here.
More recently see Submarine Matters Chart of Japan’s Soryu Submarine Combat System, and AN/BYG-1 Integration of January 27, 2016 where I wrote:
“If Japan is chosen in the CEP the US companies and Australian companies will need to work with Japanese companies to replace the Japanese combat system (below) or adapt parts of the Japanese combat which are already the same or similar to parts of the AN/BYG-1 combat system.”
Japan (with US agreement) using more of the concepts and technology in the US combat system makes sense.
Japan, the US and Australia would all benefit if Japan pooled research and production resources by adopting the US Mark 48 heavyweight torpedo.
This Japanese Soryu submarine Combat System flow chart is on Japanese technologist wispywood2344's website, passed on by S. Note that this combat system works to Japan's Type 89 heavyweight torpedo rather than the US Mark 48 torpedo. (Chart first published in Submarine Matters on January 27, 2016)