Angle-Based Sensor Network Localization

This paper studies angle-based sensor network localization (ASNL) in a plane, which is to determine locations of all sensors in a sensor network, given locations of partial sensors (called anchors) and angle constraints based on bearings measured in the local coordinate frame of each sensor. Firstly it is shown that a framework with a non-degenerate bilateration ordering must be angle fixable, implying that it can be uniquely determined by angles between edges up to translations, rotations, reflections and uniform scaling. Then an ASNL problem is proved to have a unique solution if and only if the grounded framework is angle fixable and anchors are not all collinear. Subsequently, ASNL is solved in centralized and distributed settings, respectively. The centralized ASNL is formulated as a rank-constrained semi-definite program (SDP) in either a noise-free or a noisy scenario, with a decomposition approach proposed to deal with large-scale ASNL. The distributed ASNL is solved by a distributed protocol based on inter-sensor communications. Graphical conditions for equivalence of the rank-constrained SDP to a linear SDP, decomposition of the SDP, as well as the efficiency of the distributed protocol, are proposed, respectively. Finally, simulation examples are provided to validate effectiveness of our theoretical analysis.