EM wave propagation for space-borne systems

Objectives of the course

The goal of the course is to provide the students with the theoretical knowledge and the methodologies necessary for modelling, analyzing, and designing wireless links for space-borne systems, both at radio and optical frequencies, in diversified Earth-space scenarios (e.g. Earth observation missions, satellite communications – SatCom, global navigation satellite systems – GNSS). Moreover, the course provides the students with the instruments for understanding and applying the advanced technologies used in modern wireless links. The course offers a balanced compromise between theoretical aspects and practical ones: first, the physical aspects of the phenomena are duly introduced; second, the theory behind them is addressed; third: a practical mathematical framework is derived useful for system design and analysis. The course also includes brief seminars providing an overview on “real world” systems (e.g. experimental measurements) and offers brief practical sessions focused on software tools conceived to support the design of wireless links.

Contents

Theory

  • Introduction: contents of the course and main protagonists in the history of electromagnetic wave propagation and space-borne systems.
  • The electromagnetic spectrum: frequency bands and spectrum management.
  • Main features of electromagnetic waves (frequency, wavelength, polarization, …) and electromagnetic characterizations of materials (electric permittivity and magnetic permeability, conductivity, …).
  • Basic propagation mechanisms at radio frequency and optical wavelengths (Free Space Optics): direct wave, reflected wave, evanescent waves, diffraction and Fresnel’s ellipsoids.
  • Propagation in the ionosphere. Refraction, attenuation, Faraday rotation, phase advance and group delay. Basic principles of radio-positioning in Global Navigation Satellite Systems (GNSS) and impact of the ionosphere on such systems.
  • Propagation in the non-ionized atmosphere (troposphere) and impact on Earth-space (HAPs, LEO, MEO, GEO satellites, Deep Space probes) links. Clear air propagation: refraction and ray bending, attenuation, scintillation, tropospheric scatter. Propagation through clouds.
  • Adverse weather disturbances: attenuation, depolarization, electromagnetic interference due to hydrometeors.
  • Atmospheric and extra-atmospheric noise sources: impact on the signal detection and some concepts on ground-based passive remote sensing.
  • Statistical characterization of the radio channel and system design: the link budget. Basics on fade mitigation techniques (e.g. site, frequency and time diversity, uplink power control, …).

Practice

  • Problem solving on all the topics listed above.
  • Presentation and use of the following software tools: propagation of plane waves through multi-layered materials, link budget in clear air, link budget for SatCom systems (including the impact of adverse weather conditions).
  • Mentions to ITU-R recommendation, propagation series.

Books

  • C. Riva, G. G. Gentili, Handbook of Electromagnetics, Maggioli Editore
  • A. Paraboni, M. D’Amico, Radiopropagazione, McGraw-Hill
  • J.E. Allnutt, Satellite to ground radiowave propagation, IET
  • Jean-Marie Zogg, GPS – Essentials of Satellite Navigation, u-blox https://www.zogg-jm.ch/Dateien/GPS_Compendium(GPS-X-02007).pdf

Exams with solution

Problems with solutions

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