Relationship between length of the chirp and depth of the ocean in active sonar processing

Active sonar is a fairly old area of research in ocean bottom profiling and imaging. A lot of work has already been done related to choice of signal in active sonar which shows that chirp is one of the best candidates. Previous works show that time-bandwidth product of chirp determines SNR and resolution in active estimations. This paper shows that an increase in the length of chirp does not always provide good results, rather it is dependent on the depth of the ocean. A mathematical relationship between the depth of the ocean and length of the chirp used to estimate that depth is demonstrated. Numerical results presented in this paper are in close agreement with theory.