Design of a complete simulator for underwater acoustic localization systems based on spread-spectrum signals

Abstract

Deploying prototype positioning systems in underwater environments is expensive and an especially challenging task, so a first common approach is to carry out simulated studies to evaluate the requirements and restrictions imposed by the environment. In this regard, it is helpful to have simulation models that allow the generation of a wide range of tests as a previous step to any experimental prototype implementation. For that purpose, this work focuses on the design of a simulation tool that facilitates research on underwater positioning systems by considering several parameters and features, such as the design of the signals emitted by the acoustic transducers (encoding techniques, modulation schemes, etc.), the frequency response and location of emitters and hydrophones, the bathymetry of the seabed, and the channel effects on the ultrasonic signal propagation, implemented in a model based on ray tracing for the propagation of acoustic signals. The simulation tool has been validated through a complete set of tests for different configurations and situations, analyzing the signals involved at different processing stages: baseband, modulated signals, received signals, and final estimated positions. This simulation tool is a valuable asset to research different positioning system configurations or to illustrate several concepts in a pedagogical context.