Innovations: The importance of keeping time

Israel’s Ministry of the Economy has approved a large-scale program in which the next generation of Israel's atomic Clocks will be designed at BGU.

By ADAM GONN
Atoms are cooled by laser radiation to very low temperature (photo credit: AVI KATZ)
Atoms are cooled by laser radiation to very low temperature
(photo credit: AVI KATZ)
In a world in which everything moves faster and faster, making sure that your clock is keeping the right time is essential.
To this end, the chief scientist at Israel’s Ministry of the Economy has approved a large-scale program in which the Atom Chip Group of Ben-Gurion University of the Negev will be in charge of the next generation of atomic clocks for the State of Israel.
The project will be undertaken in collaboration with Accubeat, a Jerusalem-based atomic clock manufacturer whose customers include the Israel Defense Forces and the United States Air Force.
Prof. Ron Folman, head of the Atom Chip Group, explains to The Jerusalem Report the benefits of basing the clocks on ultra-cold atoms by saying that “conventional atomic clocks work with atomic vapor. That means room temperature atoms [in gas form] that have high velocities. Such clocks suffer from inaccuracies that have to do with the velocities as well as chemical reactions taking place.
“In contrast, in the cold-atom clocks, which are the goal of this project, the atoms [still in gas form] are cooled by laser radiation to a very low temperature [down to a millionth of a degree from absolute zero – minus 273 degrees Celsius) thus avoiding both of the above shortcomings,” Folman adds.
The enhanced time accuracy, Folman says, also improves the accuracy of GPS and other types of navigation devices, speeds up communications, and, in general, makes all applications requiring time more precise..
Modern GPS systems are able to pinpoint the location of the user to within one meter by calculating the signal sent by the user to four of the 24 satellites that makes GPS navigation possible. The user’s exact position is determined by a triangulation of the position of three of the four satellites, while the fourth is used to correct the non-atomic clock on the user’s device. Since the signals travel at the speed of light, if the time is off by as little as one millisecond, the position of the user will be off by as much as 300 kilometers. And while most accurate atomic clocks are only off by one second over 138 million years, any deviation in the timekeeping, and hence the accuracy, could have dire consequences for one of the prolific users of the atomic clocks and GPS – the military.
As Folman notes, keeping the right time is also vital to the smooth flow of data over wireless networks. One way to make sure that the ever-increasing demands of more and more data being transported over wireless networks runs smoothly is by making sure that all the base stations from which the signals are transmitted are running on the same time. This is achieved by fitting the base station with a holdover clock, which makes sure that the station keeps track of time even when it’s not receiving information about the time from an outside source, like a GPS satellite.
One area in which the need for exact timekeeping, accurate positioning and an uninterrupted flow of data is of utmost importance is related to the proper functioning of the steadily increasing number of position-based smartphone applications – be they navigation apps such as Waze, the Moovit public transport information app or many of the so-called mobile-wallet apps.