Recently, localization technology is highlighted as mobile devices become popular. The existing WPAN positioning system is made up of tags, anchors, and a base station. Anchors are simply responded to TWR messages from  tags, a tag initiates TWR messages to get range measurements between anchors and itself, and a base station collect range information from tags to resolve tag positions assuming that anchor positions are already known. In the conventional WPAN location systems, anchors are installed at fixed position so that anchor position information in the base station is not changed. In an environment without infrastructure, however, it is difficult to install the anchors before-hand. In order to implement an WPAN location system without infrastructure, this paper proposes a mobile node that can be operated in either anchor or tag mode. Moreover, a base station for cooperative localization is designed to manage anchor/tag list dynamically and control the mode of mobile nodes. Using the Nanotron’s WPAN ranging modules, the proposed cooperative localization system is implemented and its performance will be analyzed.

Keywords: mobile WPAN node, WPAN positioning system, TWR, localization, cooperative positioning, Nanotron board