Underwater breadcrumb localization

In most cases, underwater localization implies a fusion of two or more sensors, usually inertial and acoustic ones. Acoustic localization demands the deployment of the acoustic baseline if precise measurement is needed. Using a fixed predeployed baseline limits the accuracy of location estimates outside certain operating areas defined by the baseline. In case an AUV or a diver has to be localized underwater, their trajectory is usually unknown, so it is a challenging task to deploy a baseline in such a manner that localization is accurate. In this paper, the sequential deployment of acoustic breadcrumb modems is suggested as the alternative to the conventional baseline deployment. This type of sequentially deployed acoustic baseline in combination with IMU is first simulated and later on tested in a constrained environment in shallow waters in order to show what are the main challenges, advantages and potential problems with this type of localization.