###### Abstract
Therefore, the primary job of SSNs is to gather environmental data and transmit them to a centralized location or processing system, such a Smart Fusion Server, for evaluation and decision-making. By now, it ought to be obvious how challenging it is to create USSNs since various resources contribute to its intricacy. Nonetheless, in this article, we specifically discuss the following [7; 11; 12]: since a distributed system's architecture consists of many heterogeneous components, it is a complicated system by itself. This indicates that it will be challenging to analyze, design, and deploy USSNs. Certainly, you can expand upon the importance of the design of the USSN and the potential consequences of design mistakes  
Figure 1: Centralized, hierarchical, and distributed fusion architecture. throughout the deployment phase of any USSN project. This is due to the fact that, in the USSN life cycle, the design phase is performed first, coming before the deployment phase. We focus our research on the applications for the Marine Observatories (MOs), which have a common concept but employ diverse technologies. More specifically, our research's focus is dedicated on the Marine e-Data Observatory Network (MeDON) (Figure 2). The MeDON project [13] relies on USSNs in order to enable continuous ocean observation. MeDON uses various communication protocols (REST, SOAP, and executive ones) to connect its various physical and logical components (e.g., Smart Sensors, Smart Fusion Servers, and Object Localization Algorithms), and together, these sensors gather data, which is subsequently transferred to the assigned workstations where it operates as a complex distributed information system. This indicates that the structure of MeDON [13] is similar to that of the USSN system, meaning that the issues we previously discussed regarding the complexity and challenges encountered during the USSN project's design and deployment also arise during MeDON's design and deployment. Accordingly, our scope in the MeDON project revolves around the intricate design of the USSN and the associated mechanisms for locating underwater moving objects. This aspect of the project is critical for achieving its overarching goals, which include monitoring and understanding the marine environment. According to [14], the complexity of the design phase is due to: (1) the several expertise domains (information systems, business process, and underlying infrastructure modeling) that the designer(s) must possess in order to model and explain such systems; (2) the MeDON/USSN Information System's distributed software structure (Figure 2), which is characterized by the fact that individual components, such as Smart Fusion Servers and Smart Sensors, are accountable for meeting specific requirements; and (3) the high levels of accuracy that must be met by the designer(s) for each component that must be deployed underwater throughout the design phase, especially for the physical components such as Smart Sensors. For this purpose, an information system like MeDON or any other USSN has a complicated design phase that demands meticulous attention to detail. In light of this, mistakes/errors committed during this vital phase might have a significant and negative impact on the project's overall performance [7; 11; 12]. Figure 2: MeDON’s run-time (based on Distributed Fusion Architecture (Figure 1)—an example: N = 6 Smart Sensors and Y = 3 Smart Fusions Servers). In terms of our contribution in the MeDON project, we are involved via underwater tracking moving objects. In order to deliver such high-level services, we have to be careful not to make any mistakes during the design phase, especially when it comes to proper and appropriate deployment. Otherwise, this has a negative impact on the overall performance of the MeDON project (e.g., inaccurate object localization in our case). The next section will go into more detail about these detrimental effects.