1. A machine-implemented method of simulating an acoustic received signal arising from an acoustic source signal scattered by a target having a plurality of highlights, the method comprising the unordered steps of: storing in a data memory information representing the properties of the acoustic source signal; storing in the data memory information representing the geometric relationship of the positions of the acoustic source signal, the acoustic received signal and the target; storing in the data memory a class library including a target class having a plurality of methods, a highlight base class and one or more highlight subclasses each having a plurality of methods; instantiating from the stored class library a target object representing the target; instantiating from the stored class library a highlight object representing one or more of the target highlights; executing a plurality of the methods in the target and highlight objects to produce the simulated acoustic received signal; and displaying the simulated acoustic received signal.