This paper describes an ultrasonic tagging system developed for robustly observing human activity in a living area. Using ultrasonic transmitter tags with unique identifiers, the system is shown through experimental application to be able to track the three-dimensional motion of tagged objects in real time with high accuracy, resolution and robustness to occlusion. The use of an ultrasonic syst...

The random deployment process and the unpredictable movement of sensor nodes lead to a high demand for an exact and reliable self localization process. Existent methods are mostly not feasible on strongly resource limited sensor nodes with an absolute minimum of energy. Thus, this paper describes the "Distributed Least Squares (DLS)"-algorithm that reduces the needed amount of energy to a minim...

The Federal Aviation Administration (FAA) is seeking to develop alternative position navigation and timing (APNT) systems in order to minimize the impact of a degradation of the Global Positioning System (GPS) and other Global Navigation Satellite Systems (GNSS). The developed APNT system needs to have capabilities beyond those provided by currently existing FAA ground based navigation aids are...

We provide primitives for uniquely localizing WSN nodes. The goal is to maximize the number of uniquely localized nodes assuming a fully decentralized model of computation. Each node constructs a cluster of its own and applies unique localization primitives on it. These primitives are based on constructing a special order for multilaterating the nodes within the cluster. The proposed primitives...