# Sensing in Inland Waters to Promote Safe Navigation: A Case Study in the Aveiro's Lagoon
## 1 Introduction
waters [12; 18]; however, updated buoys and lateral markers indicate safe routes [1; 18], and depth sounders provide real-time information on water depth under the boat keel [19]; and (v) complex interface designs that delay sailors' decision-making [20; 21; 22]. The challenges posed by maritime environments highlight the importance of using and leveraging advanced navigation technologies and systems, such as hybrid satellite-terrestrial communication networks, autonomous systems, and digitalization to enhance navigation safety and efficiency [23; 24; 25]. Hence, the most accurate and localized meteoceanographic forecasts are necessary to anticipate and manage adverse conditions effectively. In Portugal, the Ria de Aveiro, a coastal lagoon on the west coast [14; 26], exemplifies these challenges. The lagoon's shallow depths and the non-linear tidal propagation in most navigation channels highlight the need for precise and reliable navigational aids and forecasting tools. Although the system can operate in both coastal and inland contexts, the Ria de Aveiro is particularly important for this research field--maritime navigation studies--as an estuarine inland waterway, a setting that is rarely explored. To fill the gap in existing information systems capable of sharing and updating real-time navigability data, a comprehensive system for the visualization and sharing of meteorological and oceanographic data is presented in this article, encompassing the following features and benefits: (i) real-time data collection using existing boats sensors allows real-time data to be collected about the local water depth, currents, water temperature, and weather conditions (wind speed and direction); (ii) hydrodynamic and weather forecasting using weather and hydrodynamic models to predict wind and tidal behavior along water channels; and (iii) a low-cost and user-friendly platform for sharing and visualizing real-time and forecasted data. This novel maritime data sharing system using IoT technologies, specifically designed to enhance navigation in both inland and coastal waters, including offshore environments, uses low-cost electronic components to enable sailors to access and share real-time and deferred oceanographic, meteorological, and vessel data. The distinguishing feature of this system is not solely its competitive pricing, but also the use of local tidal predictions from a dedicated hydrodynamic model that provides real-time navigational information, namely the tidal height at any given point or moment in the inland water plan, and the augmented routes within the Ria de Aveiro (an augmented route contains refers to a navigational path that has been augmented with supplementary, real-time, or dynamic data, such as tide height information, which is of paramount importance for determining navigability conditions). Furthermore, the system enables the sharing of vessel-specific data, including speed over ground, heading, and direction, aggregated with meteorological and oceanographic updates. The selection of the Ria de Aveiro as a case study underscores its unique characteristics and navigational challenges. Leveraging this technology provides real-time meteorological data, enhancing safety in intricate maritime environments. As we move forward, the integration of Information and Communication Technology (ICT) and emerging technologies like Big Data and Artificial Intelligence will continue to shape the maritime industry, fostering safer and more efficient operations. The research's primary objective is to illustrate the system's potential to enhance maritime navigation safety. A Contextual Design approach [27] is employed to adapt the system to meet the specific needs of sailors, addressing a gap in existing solutions by offering an innovative, cost-effective approach to enhancing navigational safety and efficiency, assisting vessels while navigating. It is expected to contribute to the existing knowledge by presenting a practical solution to the navigational challenges faced in inland and coastal waters.