Quadrotor pose estimation and real-time control using UWB-based bidirectional measurements of distance and angle of arrival

This paper presents a new approach to quadrotor state estimation and control using ultra-wideband (UWB)-based bidirectional ranging and angle of arrival (AoA) measurements. This method offers a significant advantage over traditional motion capture systems or time-of-arrival (ToA) based positioning by requiring only a single, compact UWB anchor, greatly simplifying setup and reducing infrastructure requirements. We address the challenge of significant noise in UWB measurements by integrating them with an inertial measurement unit (IMU) data through an extended Kalman filter (EKF). Our key contributions also include proposing a magnetometer-free yaw estimation method utilizing bidirectional AoA measurements. This method effectively addresses gyroscope drift in indoor environments where magnetometers are unreliable. We also provide theoretical validation of the system's observability, and experimentally demonstrate successful stabilization control of a micro quadrotor using the estimated states. The experimental results show significant reduction in estimation errors compared to raw sensor data. Additionally, we conduct control experiments in rainy environments and confirm that UWB-based control can be effective in a wide range of conditions, including rainy weather. Our approach offers a robust, cost-effective solution for quadrotor navigation and control in GPS-denied environments, particularly indoors, and in rainy conditions, while minimizing setup complexity and hardware requirements.