RPAS navigation and guidance systems based on GNSS and other low-cost sensors

A new navigation system for small size Remotely Piloted Aircraft Systems (RPAS) is presented, which is based on Global Navigation Satellite System (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU), Vision Based Navigation (VBN) and other low-cost avionics sensors. The objective of this research is to design a compact, lightweight and relatively inexpensive Navigation and Guidance System (NGS) capable of providing the required navigation performance in all phases of flight of a small RPAS, with a special focus on precision approach and landing, where VBN techniques can be fully exploited in a multisensory integrated architecture. Additionally, the potential of carrier-phase GNSS for Attitude Determination (GAD) is explored and a six-degree-of-freedom (6-DoF) Aircraft Dynamics Model (ADM) is adopted to compensate for the MEMS-IMU sensor shortcomings in high-dynamics attitude determination tasks. The NGS data fusion architectures investigated are based on Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) approaches. After introducing the key hardware and software features of the NGS, the system performance is evaluated in a small RPAS integration scheme (i.e., AEROSONDE RPAS platform) by exploring a representative cross-section of this RPAS operational flight envelope, including a variety of high dynamics maneuvers and CAT-I to CAT-III precision approach tasks. The performance evaluation shows that the position and attitude accuracies of the proposed integrated navigation and guidance systems are compatible with the Required Navigation Performance (RNP) specified in the various RPAS flight phases, including precision approach down to CAT-II.