In this paper, we address the problem of relative localization of two mobile agents. Specifically, we consider the Dual-IMU system, where each agent is equipped with one IMU, and employs relative pose observations between them. Previous works, however, typically assumed known ego motion and ignored biases of the IMUs. Instead, we study the most general case of unknown biases for both IMUs. Besides the derivation of dynamic model equations of the proposed system, we focus on the observability analysis, for the observability under general motion and the unobservable directions arising from various special motions. Through numerical simulations, we validate our key observability findings and examine their impact on the estimation accuracy and consistency. Finally, the system is implemented to achieve effective relative localization of an HMD with respect to a vehicle moving in the real world.

翻译：本文解决双移动智能体的相对定位问题。具体而言，我们考虑双IMU系统，其中每个智能体配备一个惯性测量单元（IMU），并利用两者之间的相对位姿观测。然而，以往研究通常假设自运动已知且忽略IMU的偏置。相反，我们研究两个IMU均存在未知偏置的最一般情况。除了推导所提出系统的动力学模型方程外，我们重点分析其可观测性——包括一般运动下的可观测性以及各类特殊运动引起的不可观测方向。通过数值仿真，我们验证了关键的可观测性结论，并考察其对估计精度与一致性的影响。最后，该系统被实际部署以实现头戴显示器（HMD）相对于真实世界中运动车辆的有效相对定位。