Development of inertial navigation system with applications to airborne collision avoidance

Last years, the market growth of UAV is increasing day by day. This market growth is not just for some typical applications, but also application areas are increasing, too. This demand also increases the market value of the UAV. For competition in the market, UAV companies try to develop UAVs more efficient, cost effective and adding different capabilities. However, this growth generates some dangerous situations, moreover, because of the growth in application area, common UAVs are become not enough for applications or missions. In this thesis, I present and demostrate INS-AHRS Design and also Flight Management System with Collision Avoidance for UAV. These algorithms and demonstrations are made by the funding of ITU Control and Avionics Laboratory. In Laboratory, we already have autopilot system for multi-copter platforms and fixed-wing platforms. Before development of this INS-AHRS, we used other products from industry. But these products do not let you manage all system. But with the growth on the UAV applications, in the world also even in our laboratory, many projects required to solve specific problems with UAV. Industry products are designed for just one specific platform which may not be work on another platform. That is the main reason of necessity to develop new INS-AHRS, which can be used for multi-copter platforms. To develop INS-AHRS, filtering techniques and other conversation equations are studied. In this study, it is decided to use one IMU and one GPS. But after encounter with different problems, external magnetometer is added to the system. Then, as datasheet recommended, scaling and also alignment and offset shifting is studied. Before developing the all system, for inner loop, controller all need is attitude and attitude rate feed back. So first, with complimentary filter, gyroscope and accelerometer filtering is developed and tried to test at outside. In simulation, decision of coefficient of complimentary filter is easy to find. But these coefficients do not work at the outside. This shows the most important challenge that simulation platform can never be the same with outside real flight. For INS design, inertial frame to NWU frame conversation is developed. Accelerometers gravity vector and Coriolis vector is removed. Gyroscope outputs are also converted to the NWU frame. At least, all sensor outputs become the type of navigation frame. Whenever all datas gathered are become the type of the same frame, kalman filter is designed for INS. AS a result of INS-AHRS design, after 6 months of testing with other industrial INS, final coefficient of both INS and AHRS is decided. After few more development, test videos are recorded. For the growth of the UAV problem, this thesis presents Flight Management System (FMS) with multi-level autonomy modes that meet the requirements of future flight operations for unmanned aerial systems (UAS). It is envisioned that the future of airspace will become highly heterogeneous and integrate non-standardized aerial systems. In that case, only ground systems will be able to predict future trajectories based on performance models (stored in huge parametric databases). Meanwhile, airborne systems are required to share information. The proposed FMS structure integrates new functionalities such as (1) formal intent and information exchange and collaboration in tactical planning utilizing air-to-air and air-to-ground data links and (2) decentralized, short-term collision detection and avoidance. The air-to-ground data link enables intent sharing and allows field operators (i.e., flight operators or air traffic controllers) to interpret, modify, or re-plan UAS flight intent. The onboard FMS persistently monitors the airspace, tracks potential collisions with the other aircraft and the terrain, and requests re-planning when it detects a possible issue. When an immediate response is needed, the onboard FMS generates a 3D evasive maneuver and executes it autonomously. Flight traffic information is obtained from ADS-B/In transponders and air-to-air data links. ADSB-In/Out implementations make the unmanned systems more visible to the systems in 3D. In addition, the air-to-air data links enable intent sharing between airborne systems and are traceable in four dimensions (i.e., space and time). The experimental FMS was deployed in quadrotor UASs and a ground station and GUI was designed to perform demonstrations and field experiments for the issues introduced in the paper.