Journal of Aeronautics & Aerospace Engineering
Open Access
ISSN: 2168-9792
+44-20-4587-4809
ISSN: 2168-9792
+44-20-4587-4809
Roberto Sabatini, Subramanian Ramasamy and Alessandro Gradi
Accepted Abstracts: J Aeronaut Aerospace Eng
A novel integrated navigation system designed for small size Unmanned Aerial Vehicles (UAVs) is presented. The proposed system is based on a number of low-cost avionics sensors, including Global Navigation Satellite Systems (GNSS), Micro- Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU) and Vision Based Sensors (VBS). The use of an Aircraft Dynamics Models (ADMs) to provide additional information to compensate for the shortcomings of Vision Based Navigation (VBN) and MEMS-IMU sensors in high-dynamics attitude determination tasks is also considered. Additionally, the research concentrates on the potential of carrier-phase GNSS for Attitude Determination (GAD) using interferometric techniques. The main objective is to design a compact, light and relatively inexpensive system capable of providing the required navigation performance (position and attitude data) in all phases of flight of small UAVs, with a special focus on precision approach and landing, where VBN techniques can be fully exploited in a multi-sensor data fusion architecture. An Extended Kalman Filter (EKF) is developed to integrate the information provided by the different sensors and to provide estimates of position, velocity and attitude of the UAV platform in real-time. Three different integrated navigation system architectures are implemented. The first architecture uses VBN at 20 Hz and GNSS at 1 Hz to augment the MEMS-IMU running at 100 Hz. The second mode also includes the ADM (computations performed at 100 Hz) to provide augmentation of the attitude channel. The third fusion architecture uses GNSS based attitude values. The simulations are carried out on the AEROSONDE UAV performing high-dynamics manoeuvres representative of the UAV operational flight envelope. Simulation of the VBNIMU- GNSS (VIG) integrated navigation system shows that, the system can attain position, velocity and attitude accuracies complying with Category Two (CAT II) precision approach requirements. Simulation of the VBN-IMU-GNSS-ADM (VIGA) system also shows promising results, since the achieved attitude accuracy is higher using the ADM-VBN-IMU than using VBN-IMU only. However, due to rapid divergence of the ADM virtual sensor, there is a need for frequent re-initialisation of the ADM data module, which is strongly dependent on the UAV flight dynamics and the specific manoeuvring transitions performed. In the simulation of the third integrated navigation system, the VIG system is augmented by employing the GAD, forming the VIG-GAD (VIGGA) system architecture. The performances achieved with the VIG, VIGA and VIGGA integrated Navigation and Guidance System (NGS) are presented and are in line with the International Civil Aviation Organization (ICAO) precision approach requirements.
Roberto Sabatini has over 22 years of professional experience in Research, Development, Test and Evaluation (RDT&E) of Aerospace Electronic Systems for Military and Civil applications. He is an expert in the design, integration, test and certification of Aerospace Sensors and Integrated Systems, with specific hands-on competence in advanced Avionics and CNS/ATM systems, including GNSS, RADAR, IR/EO, SATCOM, Data Links and Route Planning/Trajectory Optimisation. He graduated with a PhD in Avionics Electro-Optical Systems from the Department of Aerospace, Power and Sensors of Cranfield University (2003). He also obtained a third level Doctor of Engineering degree in Astronautics from Rome University ?La Sapienza? and an MSc in Navigation Technology from the University of Nottingham (1997). He has served several years as a Military Officer (Lieutenant Colonel), Flight Test Engineer (Electronic and Avionic Systems) and Acquisition Manager in the Air Force/MoD and in the US Department of Defence (Joint Program Executive Office for Joint Tactical Radio System - MIDS International Program Office). He was awarded several professional and scientific recognitions both nationally and internationally. He has published numerous scientific papers, technical volumes, textbooks and research reports on avionics sensors, communications, electro-optics, CNS/ATM and satellite navigation systems, focusing on various aspects of design, integration, verification and certification.