Cooperative indoor position location using the parallel projection method

Indoor positioning has become a hot research topic due to a plethora of interesting applications ranging from emergency responder tracking to location-based services. In this work we focus on the problem of network localization also sometimes called collaborative localization where a network of nodes is to be localized using both connections to anchors (when they exist) and connections between unlocalized nodes [1]. Although several algorithms have been investigated in the literature (e.g., [2]), most have assumed line-of-sight (LOS) propagation which is uncommon in most indoor environments. Although the impact of non-LOS (NLOS) propagation has been considered in the literature (e.g., [3], [4]), this has typically been limited to traditional single-node localization such as location estimation in cellular systems. Specifically, in this work we propose a technique for collaborative position location designed to effectively handle NLOS propagation and demonstrate the performance improvement possible over existing methods.