In active sonar a sound wave is generated that spreads outward and is reflected Back by a target object. Passive systems consist simply of receiving sensors that pick up the noise produced by the target (such as a submarine or torpedo).

• 在有源声纳系统中,声发射装置发出的声波向外传播并被目标反射回来。无源声纳系统仅具有接收目标(如舰船、潜艇或水雷)所发噪音的接收传感器。