Patent ID: 7266040

Claim:
A method in a data processing system for simulating a realistic sounding active sonar signal that originates from a simulated sonar transmitter, the simulated sonar signal being acted upon and modified by simulated ocean effects and then being received by a simulated hydrophone, the sonar signal being acoustically displayed within a simulated ocean acoustic environment that further incorporates realistic sounding simulated reverberation comprising: a. creating an ocean physical data file for storing ocean physical data; b. creating a noise file for storing the acoustic signatures of the ocean environment; c. retrieving random samples from the noise file; d. filtering the random samples retrieved finn the noise file; e. retrieving physical data from the ocean physical data file for calculating reverberation; f. calculating reverberation decay using inputs from the physical data file; g. modifying the random samples retrieved from the noise file with the calculated reverberation decay; h. mixing the modified random samples to create a reverberation emulation signal; i. defining distance data, velocity data, aspect pattern data and strength data for contacts of interest; j. defining data for sonar platform location and velocity; k. selecting a base signal frequency; l. selecting a sonar transmission frequency; m. initiating a simulated transmission of a sonar transmission signal at the sonar transmission frequency; n. calculating a doppler shift for the contacts at the sonar transmission frequency using inputs of the data for the contacts of interest and the data for sonar platform, location and velocity; o. correcting the base signal frequency for the doppler shift; p. correcting the base signal for propagation loss; q. calculating time of return for the base signal, the time of return being equal to the time of return of the simulated transmission signal at the sonar transmission frequency; r. mixing the base signal with the reverberation emulation signal; and, s. outputting the mixed signal.