Echo detection for localization I was reading about active sonar and couldn't quite understand how the echos are recognized.

My doubt is, when the sound signal is reflected back, it is greatly attenuated and distorted due to many factors.

Do they use MFCC(which I think is only good for audible range) for identifying the echo or are there any other better techniques? I feel that the problem is modeled and the echo data is fit to the model but I am not sure.
My doubt is, when the sound signal is reflected back, it is greatly attenuated and distorted due to many factors.


That's true!


  Do they use MFCC(which I think is only good for audible range) 


I don't see how MFCC come into play here, at all. Radar/sonar applications typically depend on some kind of comparison between TX and RX, and a power spectrum only observation can't help you at all here.


  for identifying the echo or are there any other better techniques?


yes, there are – for example, simple cross-correlation would do.