Analysis of Sonar Signal Design Alternatives in a Dispersive Medium

The detection performance of several modulation schemes is compared when employed in the underwater medium characterized by multiple paths and doppler dispersion. Analysis is made on the basis of the signal ambiguity function and the medium spreading function which allow evaluation of sonar signals for a wide variety of medium characteristics. It is shown that phase coded pulse trains are optimum against moving targets. However, when medium spreading limitations are introduced, frequency coding becomes more profitable.