Abstract—Recent advances in the technology of wireless electronic devices have made possible to build ad–hoc Wireless Sensor Networks (WSNs) using inexpensive nodes consisting of low power processors, a modest amount of memory, and simple wireless transceivers. Over the last years, many novel applications have been envisaged for distributed WSNs in the area of monitoring, communication, and control. One of the key enabling and indispensable services in WSNs is localization (i.e., positioning), given that the availability of nodes’ location may represent the fundamental support for various protocols (e.g., routing) and applications (e.g., habitat monitoring). In the depicted context, the present contribution reports our recent research advances along two main directions: i) first of all, we provide a comparative analysis of various optimization algorithms that can be used for atomic location estimation, which include: Triangulation, Steepest Descent, Non–Linear Least Squares, C...