Space navigation systems and the role of clocks. The adopted solutions in the existing GPS system and in the planned Galileo system

Presenter Name
Prof. Sigfrido Leschiutta

Affiliation
Dipartimento di Elettronica,
Politecnico di Torino, Corso
Duca del Abruzzi, 24,
Torino, Italy

Photography

Biography
Sigfrido Leschiutta is born in Rome in 1933. After a title in Electrical Enginering at Politecnico di Torino, he got "the libera docenza", a degree equivalent to the Ph.D. in Radio and Electronic Measurements. He joined the Italian National Bureau of Standard working in the Time and Frequency Department.  Activities were performed on three topics, construction of a Time scale, in order to derivate time signals to be broadcasted with HF Radio transmitters, special equipment and frequency standards,
piezoelectric and atomic ones.  Following technological  developments, equipment were designed for VLF emissions, OMEGA, LORAN-C and for the application of the so-called TV-Method.  Meanwhile  experiments and services were performed using satellites, such as the Applied Technology Application Satellites,  TRANSIT, GOES and in recent years, with GPS satellites. Presently he is involved in research connected with the planned GALILEO European navigation System.
Leschiutta was vice-chair for the CCIR Study Group VII, and chair of the Italian Space Research Committee. For eigth years he was chair if the Istituto Elettrotecnico Nazionale, the Italian standards Laboratory for Electrical Quantities and Time and Frequency.  He is now a member of the International Committee for Weigths and Measures and chair of the Consultative Committee for Time and Frequency. At the University he is full professor on Electronic Measurements, Time and Frequency Metrology and Space navigation Systems.

Presenter Name
Prof. P. Tavella 

Affiliation
Istituto Nazionale di Ricerca Metrologica (I.N.R.I.M.), formerly IEN
Strada delle Cacce, 91,
Torino, Italy

Photography

Biography
Patrizia TAVELLA, received the degree in Physics from the University of Torino and the Ph.D. in Metrology from the Politecnico of Torino, Italy. She is now senior scientist with the Istituto Elettrotecnico Nazionale, Torino, Italy.
Her main interests are mathematical and statistical models mostly applied to atomic time scale algorithms and to the uncertainty evaluation of atomic clock measurements.
She is currently involved in the development of the European Navigation System Galileo. She collaborates with the Bureau International des Poids et Mesures, and she chairs the  working groups on “International Atomic Time” and “Algorithms” of the Consultative Committee of Time and Frequency.

Abstract
The outstanding performances of the Global Positioning System (GPS) offering localisation and time dissemination services at a very high accuracy and reliability level have started a lot of applications and uses that were not expected years ago.
Europe is developing a new satellite navigation system, Galileo, that will be independent but interoperable with GPS from 2008 and that will offer also additional services. The heart of a navigation systems are atomic clocks that allow very precise time and hence position measurements.
The tutorial intends to give a broad overview of the GPS and Galileo systems, presenting also the fundamental role of time and frequency measurements.
The tutorial aims in giving useful information either to whom may be interested in using GPS or Galileo to different positioning or timing application, or to whom may use similar measurement techniques in different field of applications.
The tutorial proposes:
The very general principles and the nomenclature as regards the orbits and the space navigation. Different types of navigation and their requirements regarding the electronic measurements.
The role of the atomic clocks and of time scales in the spherical navigation.
Main Characteristics of the existing Global Positioning System and of the future GALILEO System to be operative in 2008-2009.
Some peculiar solutions for some very peculiar requirements, mainly for the use of these systems to the air navigation and sea navigation in restricted areas.

Target audience
Engineers and technical staff involved in satellite systems, telecom systems, time and frequency measurements, and navigation system applications.