• critical context
• distributed measurement systems
• harsh environment
• industrial application
• LoRaWAN
• monitoring

Distributed measurement systems are becoming increasingly crucial for efficient and reliable monitoring not only in the industrial world but also in the vast environmental paradigm. These systems aim to offer significant advantages regarding performance, safety and sustainability, based on data collected on a large scale. The heart of these systems lies in the integration of key components that first allow data acquisition, then transmission and finally data processing to provide information to the end user. The first fundamental components in distributed measurement systems are sensors, which allow the monitoring of physical or chemical quantities such as temperature, humidity, pressure, concentrations and so on. In addition to the measured quantity, sensors differ in their characteristics: accuracy and resolution, stability, response time, power supply, compatibility with the environment and so on. Then, another indispensable pillar in distributed measurement systems is the communication part. In fact, sensors must be able to communicate with the control nodes and the data processing center. Communication methods divide into wired and wireless, and data transfer relies on specific protocols. Obviously, the acquisition, processing and data transfer are made possible by one or more control units that manage the various operations. Examples of control units are Micro Controller Units (MCUs), Central Processing Units (CPUs) and Programmable Logic Controllers (PLCs); each of these has different characteristics with their advantages and disadvantages. For example, MCUs integrate the processor, memory and I/O interfaces into a single chip; furthermore, thanks to their low energy consumption and low cost, they are widely used in distributed measurement systems to manage data acquisition and logic actuation, as well as data transfer. In contrast to MCUs, CPUs enable a much higher workload and are therefore integrated into data acquisition servers and central processing nodes. Finally, PLCs are widely used in industrial environments given their excellent characteristics of robustness, reliability and ease of integration; usually, they are usually not used in the context of distributed measurement systems because of their high cost and large size. Finally, each of the units that are part of distributed measurement systems relies on different types of software to manage their specific functionalities. This Thesis explores the field of distributed measurement systems in critical environments, leveraging emerging and non-emerging technologies to overcome data transmission challenges in harsh conditions. Among the technologies used, this Thesis addresses a detailed analysis of critical environment applications using Long Range Wide Area Network (LoRaWAN) transmission technology. Through a series of experiments and analyses, the research sheds light on the potential of LoRaWAN in scenarios such as transmission through a layer of ice or from moving vehicles, but also characterised by wide temperature and humidity ranges, the presence of corrosive and non-corrosive gases (e.g., nitric oxide, nitrogen dioxide and carbon monoxide) or the presence of vibrations. These contexts represent the test bed for evaluating the effectiveness of LoRaWAN and its potential use in distributed measurement systems, which require reliability and robustness. After this initial analysis, the research focuses on the performance of LoRaWAN transmission through metal barriers, examining the effectiveness of the technology in the context of condition monitoring and predictive maintenance. This part also shows an industrial application where a system, including a LoRa module, enables condition monitoring of a gas turbine igniter, embedded in an ATEX certified metal box. Long-distance data transmission technologies, such as LoRaWAN, can pave the way for a wide range of applications in various sectors, but they have limitations that prevent their use in many others. In fact, this Thesis also proposes a system for analysing coastal erosion, using 3D reconstruction methodologies, which does not involve the use of LoRaWAN, but rather other more established transmission technologies such as RFID and GPS. Next, the work explores applications of underground-to-aboveground transmission, using LoRaWAN, highlighting how the technology supports the collection of essential data in construction sites and agricultural environments. Then, these results pave the way for the development of a system for monitoring and analysing vertical ground movements via a distributed, multi-layered sensor network. This Thesis addresses the application and analysis of different technologies in distributed measurement systems, setting the stage for future developments and suggesting solutions that can overcome barriers traditionally considered complex.