This letter proposes a novel distributed bearing-based pose estimator for time-varying multi-robot systems. The method uses angles computed from body-frame bearings to estimate the robots' positions in $\mathbb{R}^3$ without knowledge of their orientations. The orientations in $\mathrm{SO}(3)$ are recovered from the estimated positions, the bearings, and the bearing derivatives. The proposed observer only requires the (directed) sensing topology to be \textit{angle-rigid}, a weaker condition than the commonly used ones like bearing rigidity. Local uniform exponential stability of the proposed observer is established under the assumption of persistently exciting motions for a subset of robots. Simulations are presented and discussed to evaluate the scheme's effectiveness and practicality.

翻译：本文针对时变多机器人系统提出了一种新型分布式仅方位姿态估计器。该方法利用从本体坐标系方位角计算出的夹角，在无需已知机器人朝向的情况下估计其在$\mathbb{R}^3$中的位置。随后通过估计位置、方位角及其导数恢复$\mathrm{SO}(3)$中的朝向。所提出的观测器仅需（有向）感知拓扑满足\textit{角度刚性}条件——该条件弱于常用的方位刚性等约束。在假设部分机器人运动持续激励的条件下，证明了该观测器具有局部一致指数稳定性。通过仿真实验验证并讨论了该方案的有效性与实用性。