44531 - Navigation Data Processing

Learning outcomes

The aim of the course of Navigation Data Processing is to provide the students of the third year of Aerospace Engineering bachelor's degree the general description of the avionics of a modern aircraft and, in particular, the architecture of the Navigation, Guidance and Control (NGC) system. The main issues related to a NGC system are presented, both with respect to the Automatic Flight Control and Air Navigation. Moreover, the characteristics of an NGC system are analyzed as a function of the main fligth phases (en route, approach, landing). The single subsystems of a NGC system are studied: the aircraft vehicle and its dynamic model, stability augmentation systems, the autopilot, the guidance and navigation system, the sensors. It is stressed the way the NGC system porcesses the fligth data.

It is recommended the knowledge of the foundamental concepts and techniques of automatic control systems, as presented in the course of Automatic Control L.

Course contents

Introduction
Automatic Flight Control and Navigation Systems: problems and definitions. General functional architecture of a Navigation, Guidance and Control (NGC) system. Examples.
Aircraft Dynamics

Reviews of flight mechanics and dynamics principles. The non-linear aircraft dynamic model. Aerodynamic forces and moments. Linearization and longitudinal-lateral dynamics separation.
Stability Augmentation Systems (SAS)
SAS: behaviour and architecture. Flight-By-Wire (FBW). SAS for lthe ongitudinal dinamics (stick/pitch-rate) and for the lateral dynamics (steering-wheel/roll-rate). Design examples.
Autopilots
Autopilot function and modes. Longitudinal autopilot: pitch angle hold, vertical speed hold, height hold. Design example. Lateral autopilot: roll angle hold, heading hold. Design example.
Guidance systems
Flight Director. Guidance kinematics. Control system for the tracking of a VOR radial or for a ILS localizer path. ILS Glide Slope tracking system. The Flare. Design examples.
Sensors and Data-Fusion
Relevant features and typical errors of a sensor. Inertial sensors. Accelerometers e gyroscopes: characteristics, technology and functioning. Devices for the materialization of vertical reference: artificial horizon, Vertical Gyro (stable-platform and strap-down). Devices for the materialization of horizontal reference: compass and flux valve, magnetometer, Dyrectional Gyro. Standard atmosphere and the exploitation of air data (static and dynamic pressure, temperature). Air data sensors: altimeter, anemometer, sensors for aerodinamic alfa e beta angles, Air Data Computer (ADC).
Fusion of data provided by different sensors. Filtering algorithms. Attitude and Heading Reference Systems (AHRS).

Readings/Bibliography

Notes provided by the teacher.

R. P. G. Collinson, “Introduction to Avionics”, Chapman & Hall, London, 1996

D. Mc Lean, “Automatic Flight Control Systems”, Prentice Hall International, 1990

M. Kayton, W. R. Fried, “Avionics Navigation Systems”, 2nd ed., John Wiley & Sons, Inc., 1997

J. Roskam, “Airplane Flight Dynamics and Automatic Flight Controls”, Voll. I and II, Roskam Aviation, 2003

Teaching methods

Teaching will be held by means of in-front lessons and exercises.

Exercitations will be carried out at the workstations by using MATLAB/SIMULINK software: the purpose is to let the student to become familiar with fligth control system design techniques assisted by the use of the computer and to implement simulation models for fligth control systems.

Assessment methods

The exam will consist of an oral test. The test will be able to be integrated with a short dissertation on a topic selected by the student among those dealt during the course.

Teaching tools

Le lectures will be carried out by means of tools such as: blackboard, video projector, overhead projector, computer.

Office hours

See the website of Matteo Zanzi