Localization is a crucial task for autonomous mobile robots in order to successfully move to goal locations in their environment. Usually, this is done in a robot-centric manner, where the robot maintains a map with its body in the center. In swarm robotics applications, where a group of robots needs to coordinate in order to achieve their common goals, robot-centric localization will not suffice as each member of the swarm has its own frame of reference. One way to deal with this problem is to create, maintain and share a common map (global coordinate system), among the members of the swarm. This paper presents an approach to global localization for a group of robots in unknown, GPS and landmark free environments that extends the localization scheme of the LadyBug algorithm. The main idea relies on members of the swarm staying still and acting as beacons, emitting electromagnetic signals. These stationary robots form a global frame of reference and the rest of the group localize themselves in it using the Received Signal Strength Indicator (RSSI). The proposed method is evaluated, and the results obtained from the experiments are promising.

翻译：定位是自主移动机器人在其环境中成功到达目标位置的关键任务。通常，这以机器人自身为中心的方式进行，即机器人维护一张以自身为中心的地图。在群体机器人应用中，当一组机器人需要协调以实现共同目标时，以机器人自身为中心的定位将无法满足需求，因为群体中每个成员都有其自身的参考坐标系。解决该问题的一种方法是在群体成员之间创建、维护并共享一个公共地图（全局坐标系）。本文提出了一种在未知、无GPS及无地标环境中实现群体机器人全局定位的方法，该方法扩展了LadyBug算法的定位方案。核心思路是利用群体中保持静止的成员作为信标，发射电磁信号。这些静止的机器人构成全局参考坐标系，其余成员通过接收信号强度指示器（RSSI）在该坐标系中进行自我定位。评估结果表明，该方法实验效果良好。