Wideband Signals for Phase Differencing Sonar Systems

Abstract

This research work deals with the resolution problem in Phase Differencing Bathymetric Sonar Systems (PDBS), also called interferometric sonars (“Interferometers”). Wideband signals are compared with the narrowband continuous wave (CW) pulses to assess the relative merits of signals to improve the range and angle resolution. The idea is inspired by the marine mammals, who use complex wideband signals for navigation and target detection. A set of waveforms e.g. CW Pulses, LFM (Linear Frequency Modulated) Pulses, EFM (Exponential Frequency Modulation) Pulses were used with Bathyswath-1 transducers for the experiment. A comparative study was done to assess the set of signals for range and angular resolution of Interferometers. Wideband signal processing techniques are used to solve the problem of trade-off between range and resolution. This paper gives an introduction to interferometry sonars, the major problems with them and the wideband processing approach to improving them.