Localization and navigation methods have suffered deep changes in the last century after the introduction of radiowaves and satellites. Knowledge form many disciplines is needed to describe the new satellite systems for navigation, the course is mainly concerned with electronic systems of frequency and time measurements.

General introduction to navigation systems, reference systems and time measurements; characteristics of the electromagnetic wave propagation and Doppler effect. Radionavigation and geometric loci: cones, hyperboloids, spheres. Measurements by interferometric methods, electronic measurements: frequency variations, time of flight and time of arrival.
Propagation in dispersive media and in particular in the ionosphere.
Electromagnetic oscillators: principle of operation and examples. Representation of short-term and long-term frequency instabilities. Quartz resonator with equivalent circuit, quartz oscillators: examples and characteristics. Comparison between piezoelectric clocks and atomic clocks, operation and performance of a Rb clock.
Satellite systems, properties of Keplerian orbits. GPS signals, frequencies used and transmission times. Signal received, time of arrival measurements and phase comparison, different tipes of receivers. UERE and GDOP. Time-scale comparison between satellite and the Earth: velovity and gravity effects.
Methods used for the clock syncronization.
Integrity requested by civil air navigation, systems WAAS and EGNOS, Galileo system expected performance.

Visits to laboratories which realize time scales, atomic clocks and signal processing of GPS and Galileo signals.

Laboratory: numerical computations with quantities spread on a wide range (use of dB, Np). Numerical checks of expressions introduced at lesson.
A visit is planned to the laboratory where the Italian time scale is realized.