TABLE OF CONTENTS Determining the geographic location of nodes in a sensor network is essential for many aspects of system operation: data stamping, tracking, signal processing, querying, topology control, clustering, and routing. It is important to develop algorithms for scenarios in which only some nodes have known locations.
The design space of localization algorithms is quite large. The selection of a suitable algorithm for a given application and its performance depends upon several key factors, such as: what information about known locations is already available, whether the problem is to locate a cooperative node, how dynamic location changes are, the desired accuracy, and the constraints placed on hardware. On the basis of what needs to be localized, the location algorithms that have been proposed can be broadly classified into two categories: (i) node localization algorithms, which provide the location of a single unknown node given a number of reference nodes, and (ii) network localization algorithms, which provide the location of multiple unknown nodes in a network given other reference nodes. The node localization algorithms are often a building-block component of network localization algorithms. The accuracy of the localization algorithms is often dependent crucially upon how detailed the information obtained from reference nodes is.
The node localization algorithms we discussed include centroids, the use of overlapping geometric constraints, triangulation using distance estimates obtained using received signal strength and time difference of arrival, as well as AoA and pattern-matching approaches. For triangulation, TDoA techniques provide very accurate ranging at the expense...
