Interview with Marina Gioia, Selex-Galileo Program Manager for the Atomic Clock on Board Giove-B
Selex-Galileo, a Finmeccanica Company, supplies the remarkable Hydrogen Maser Atomic Clock for the Galileo satellite constellation of global positioning satellites. Giove B (Jupiter) is the second verification satellite launched by the European Space Agency, and the first spacecraft equipped with a hydrogen maser Atomic Clock. The Hydrogen Maser Atomic Clock has been developed and is being built in Italy. This is the first time that a highly accurate Hydrogen Maser Atomic Clock has been put into space orbit.
(photo left: Marina Gioria)
Galileo satellites will carry two types of clocks –rubidium atomic frequency standards as used in the U.S. GPS constellation, and passive Hydrogen Maser Atomic clocks (two per satellite). A rubidium atomic frequency standard loses three seconds every million years, while the Maser clock will lose only one second in three million years. The result is a more accurate positioning satellite, with accuracy reaching about 30 centimeters (11.81 inches).
An atomic clock works like a conventional clock but the time-base of the clock, instead of being an oscillating mass as in a pendulum clock, is based on the properties of atoms where transitioning between different energy states.
The name Giove –Jupiter- was selected because Galileo Galilei discovered that Jupiter’s Moons could be used as a navigation system.
“In 1610, as one of the first to turn his telescope to the sky, Galileo discovered four of the moons of the planet Jupiter. These were later named Io, Europa, Ganymede and Callisto. Galileo realized that the movements of these four natural satellites, whose eclipses are frequent and visible, provided a clock whose face could be seen from every point on the Earth.
(photo right: Official Team)
“Tables describing the motion of the first four Jovian moons to be discovered were used to determine longitude both at sea and on land. Galileo's method of determining longitude by observing the eclipses of Jovian moons heralded a revolution in navigation, geodesy and cartography in the 17th and 18th centuries.
Galileo's observations of Jupiter's moons
“GIOVE stands for 'Galileo In-Orbit Validation Element' and also refers to Jupiter, being the Italian name for the planet. Ms. Karla Peijs, then the Dutch Minister of Transport, Public Works & Water Management, announced the choice of name in November 2005, during a visit to ESA's European Space Research and Technology Centre (ESTEC) in Noordwijk (The Netherlands). The naming ceremony was part of a media event during which GIOVE-A, the first experimental Galileo satellite was presented to the press and television.” (Source: ESA)
The highly accurate Galileo system will be a new chapter in global positioning systems thanks to the Maser Atomic Clock technology.
The European General Directorate for Transport reports the following uses for the Galileo system:
Transport applications are the user category par excellence that will benefit greatly from the existence of the GALILEO system. GALILEO services will be used in every transport domain, namely aeronautical, maritime, road, rail, and pedestrian. Each user segment has its characteristic needs, and the GALILEO system is designed to satisfy all categories. GALILEO will provide an answer to current mobility and transport problems throughout the world and will make for improvements in safety and comfort.
On the roads
Road traffic ©European Commission's Audiovisual LibraryAt present, traffic congestion places enormous constraints on our day-to-day mobility with over 10% of the network blocked, representing enormous costs. Improving road transport systems calls for systematic recourse to information about vehicle position and speed. A driver using a GALILEO receiver will receive a constant supply of information to enable him or her to determine their location and find the best route. The system will therefore make for better vehicle fleet management (e.g. taxis, trucks, buses), optimum route finding and traffic optimization. Advanced Driver Assistance will include also functions for safety and mobility improvements in road traffic, such as collision warning, vision enhancement, low speed maneuvering aid, etc. Information services for road users can also be based on GALILEO.
GALILEO will also be a major impetus to the development of Intelligent Transport Systems (ITS) for the road sector.
In the air
Air Transport ©European Commission's Audiovisual LibraryAir traffic management is a major concern on account of the speed of air traffic growth and safety considerations. Systems modernization obliges Europe to introduce new aircraft monitoring applications. GALILEO will be instrumental in revolutionizing air traffic management!
Where aviation safety is concerned, a single source of information cannot be trusted, thus necessitating systems redundancy. GALILEO will be more reliable, interoperable and complementary in relation to the current systems. GALILEO could be used in the various phases of flight, i.e. in en route guidance, airport approach, landing (Cat I, II, and III), and for ground guidance, for which GALILEO could be highly beneficial where the needed infrastructure (i.e. surface movement radars) does not yet exist.
By using GALILEO, airport infrastructures could be adapted to increasing traffic while guaranteeing better traffic control and safety.
Sea Transport : Beached boat ©European Commission's Audiovisual LibraryGiven that 80% of accidents at sea are due to human error, GALILEO will provide an answer by providing constant and very precise information about a vessel's position and route, while increasing the efficiency of search and rescue facilities, whether for commercial shipping or recreational craft. GALILEO will be used as an on-board navigation means for all forms of marine transport, including ocean and coastal navigation, port approach, and port maneuvers.
On the railways
Rail Transport ©European Commission's Audiovisual LibraryGALILEO will be able to offer numerous rail transport applications, ranging from traffic, wagon and cargo control and monitoring to train signaling, track survey and passenger information services. In particular, GALILEO will make it possible to reduce distances between trains and therefore increase train frequency. In addition, it will make it easier to locate the entire rail fleet.
For all the above-mentioned applications, the GALILEO system will have a primary role, due to its inner characteristics of certification, operation transparency, and service guarantee derived from its civil nature. In addition to that, the feature of the real time navigation performance integrity monitoring (the so-called "integrity flags") over the service area, makes the GALILEO system suitable for all safety-of-life requirements.
For the traveler:
Travelers would all like to make seamless journeys where they would be able to progress easily from one part of their trip to another - whether they're first on public transport or in their car and then expect to transfer to another transport means. Congestion (10% of the network can be blocked at any one time) and service delays mean that connections can easily be lost and the trip is far from seamless. A basis of an improvement of transport system service levels is the systematic provision of information about vehicle position and speed, together with an accurate time reference. A traveler using a GALILEO receiver (incorporated into a personal communicator) will receive a constant supply of information to enable him or her to determine their location and find the best route currently available to him. These 'best choices' are constantly varying for all travelers - on the road, in cars or public transport, or using any other form of transport. The regular data from GALILEO processed by value-added service providers such as those integrating available travel information - services, congestion, events, incidents etc. - can be instantly downloaded to travelers and has an equally positive value to business users as well, whether they are moving freight or people. Freight movers are already using location and route finding systems to optimize their operations, GALILEO will enhance the possibilities available to them leading to gains in efficiency - and marketing potential in both the European internal market and international trade.