[Nexus7]

Parameters that influence your detection range (that come to mind) are:
- noise of the target (his platform type, his speed)
- target's depth and your own depth (see SSP monitor, Sound Propagation Profile, target's location SSP might be different!)
- topography of the sea bottom

and (not sure)
- sea state (flows direction and speed, temperature)
- how your TA is disposed in regards of the target (direct line from target perpendicular on TA is best) and your own speed (the TA sinks in other sound speed depths)

... meaning a lot of variables are involved and its probably not calculable in game.

I think the best thing you can do is to learn it by training missions (thats how I learned it in SC). Find another player and have him change range, speed and depth (communicate) to see the result on your sonar station. Try vs different platforms and maybe different sea states

This should give you a good awareness on detection ranges