By comparison with simple shape targets, the echostrength of the complex targets versus frequency and range is more complex.
与简单形状目标相比,复杂目标的回声强度随频率和距离的变化更为复杂。
2
When we use it to test the underwater target strength, one problem is how to discriminate the direct sound of the source with the echo reflected from the target, finding the target character quickly.