Considering that UUV has no warhead, it is plausible that it can carry a sensor suite superior to the one of a torpedo, but still limited by the size. in my understanding passive sensors partly depend on size of the array in order to be able to triangulate distance, which is clearly not going to be accurate with the size of a torpedo. But passive capability should normally still be superior to just torpedo auto director, otherwise, why would one bother to fabricate UUVs?a