Well you need good solution if the target is far away. You need great solution if your torpedo is not auto guided (WW2 torpedoes).
But in DW .. if it is far, it will detect the launch and evade. If it's near, just send the fish down the actual bearing. All you need is general distance estimate.
With DW there is problem in dense situation. Solutions gets old. You can have solution at 90, when sonar says track is 270 !. This will degrade shooting much more then bad speed estimate or distance estimate. You can of course hop to TMA and build solution manually.
But sometimes it works best with no TMA at all.
Hm .. with sub launched asroc, THEN you need quite a solution. But I had no chance to use these for a time. You need deep water, and far submerged contact. Submerged contacts have this problem that you usually detect them way too close
