Automatic Gain Control Circuit Design
Implementing an approximation of an ideal exponential time-variable gain (TVG) amplifier is certainly a viable approach in ranging applications. The fall-off of response pulse (or chirp) with time is both enormous and predictable and can be thus profitably compensated for. 

Polaroid's ultrasonic ranging system (marketed in the mid-1970s, and used for such commercial applications as door openers as well as the original application of autofocus cameras) used such a method- using an ASIC. You should be able to find the patent. 



I've designed a few such systems used for such disparate applications as extruder control, film making and vending machines. 

If you don't need a huge range, consider varying other parameters with time rather than trying to use a general purpose AGC. There are, no doubt, far more sophisticated methods that could be applied, implemented with DSP technology, chirp transmit signals, and the knowledge of the expected drop-off of return signal strength. 

Resonance (and Q) of the transducer(s) can indeed be a major factor, depending on what your actual requirements are.