Localization and tracking is a field of application subject to intense research activities, since, depending on response time and accuracy, it enables a wide array of practical applications, including for instance Surveillance, Location Based Services, and Telemanipulation. Positioning and Tracking Systems (PTSs) can be realized according to different methodologies. Typically, by deploying a set of known position anchors, both proximity sensing and range measurements followed by position estimation may be applied and combined, using sensor fusion and collaborative processing. Various sensing devices have been proposed and adopted, including inertial sensors, ultrasounds transducers, and electromagnetic signals’ transceivers, ranging from low frequency inductively coupled circuits to ultrawideband radios. Additional methods include image acquisition and processing, based on photodetectors, or application specific approaches, involving for instance use of chemical sensors. The availability of wireless sensors, i.e., measurement devices capable of processing and transmitting the collected information using radio interfaces, enables additional applications. On one hand, positioning and tracking can be realized via Wireless Sensor Networks (WSNs). On the other hand, specific applications may require usage of additional sensors. In all considered cases, when designing a positioning system based on wireless sensors, the available degrees of freedom can be affected by the sensors’ performance.