Unlike many current navigation approaches for micro air vehicles, the relative navigation (RN) framework presented in this paper ensures that the filter state remains observable in GPS-denied environments by working with respect to a local reference frame. By subtly restructuring the problem, RN ensures that the filter uncertainty remains bounded, consistent, and normally-distributed, and insulates flight-critical estimation and control processes from large global updates. This paper thoroughly outlines the RN framework and demonstrates its practicality with several long flight tests in unknown GPS-denied and GPS-degraded environments. The relative front end is shown to produce low-drift estimates and smooth, stable control while leveraging off-the-shelf algorithms. The system runs in real time with onboard processing, fuses a variety of vision sensors, and works indoors and outdoors without requiring special tuning for particular sensors or environments. RN is shown to produce globally-consistent, metric, and localized maps by incorporating loop closures and intermittent GPS measurements.

中文翻译：

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GPS退化的微型飞行器的相对导航

与当前许多用于微型飞行器的导航方法不同，本文介绍的相对导航（RN）框架可确保通过相对于本地参考系进行工作而在GPS受限的环境中仍可观察到滤波器状态。通过巧妙地解决问题，RN可以确保滤波器不确定性保持有界，一致和正态分布，并使飞行关键的估计和控制过程与大型全局更新隔离。本文全面概述了RN框架，并在未知的GPS拒绝和GPS退化的环境中进行了几次长时间飞行测试，证明了其实用性。相对的前端显示出可以利用现有算法生成低漂移估计值和平稳稳定的控制。该系统通过机载处理实时运行，融合了各种视觉传感器，可在室内和室外工作，而无需针对特定传感器或环境进行特殊调整。通过合并回路闭合和间歇性GPS测量，RN被显示为可生成全局一致的，公制的和局部的地图。