Space atomic clocks are the epitome of accuracy, and SpectraTime, a company of the Orolia group, will supply Rubidium Space Clocks to the Indian Regional Navigational Satellite System (IRNSS). With this new contract, SpectraTime is on the way to having the largest number of atomic clocks in space on-board satellites with a contract valued at approximately EUR 4 million.

The Indian Regional Navigational Satellite System(IRNSS),  developed by the Indian Space Agency ISRO, will consist of seven satellites. Three of the satellites will be placed in geostationary orbit and the four others in geosynchronous orbit. The constellation will also comprise a ground segment consisting of a Center of Principal Control and ground stations in order to follow the satellites and to guarantee the system integrity. The Indian Regional Navigational Satellite System anticipates their first launch to be in 2009, which will be able to provide an absolute position with an accuracy of 20 meters through all India and at a distance of about 2000 km beyond its borders.

The principle of navigation by satellite is based on the transmission of signals coming from at least four satellites, to the users, and in order to get precise location data, these signals must be perfectly synchronized. This is where the atomic clocks come in. The extremely precise measurement of time on board each satellite, achieved through onboard atomic clocks, is a major condition for the positioning performance of the system. In the framework of the IRNSS program, each satellite will have four SpectraTime Rubidium atomic clocks on board to reach a stability of less than 10 billionths of a second per day. "To give a point of comparison, our clocks are 10 million times more precise than a watch made of quartz," says Pascal Rochat, Chief Executive Officer of SpectraTime.

With this new contract, awarded just four months after Giove-B the second experimental satellite of the European Global Navigation Satellite System Galileo, was successfully launched, SpectraTime strengthens its competitive positions on the fast-growing GNSS market. "A worldwide satellite navigation constellation consists of 20 to 30 satellites, embarking each three to four atomic clocks. Within five years, we expect to have the largest number of space-borne atomic clocks than any other company," says Rochat.