Galileo: A new tool for Science

Last week’s start of Galileo’s initial services is a boon not just for people worldwide but also the scientific community. A precise yardstick is now freely available to study Earth and everything on it, along with the laws of physics.

The Galileo satnav system began operating on 15 December, offering positioning, navigation and timing services to everyone with a receiver. Service availability is based on a minimum of four satellites being visible in the local sky, set to improve as the number of satellites increases from the current 18 to a planned 24 plus orbital spares.

Satellite navigation in general has become an essential tool for scientists, with satnav receivers employed for instance to monitor the slow movement of tectonic zones, chart shifts in polar ice or to probe the ionosphere and other atmospheric layers.

Satnav also underpins activities such as animal tracking or drone monitoring, while the resulting timing accuracy down to a few billionths of a second allows for all kinds of precise fundamental physical measurements and experiments.

“The continuity and improved availability of Galileo provides a whole new source of positioning and timing data for scientific purposes, to be used either in isolation or in combination with other satellite constellations,” explains Javier Ventura-Traveset, leading ESA’s new Galileo Science Office.

“Galileo also offers various specific advantages for scientific use, with the Passive Hydrogen Maser atomic clocks on each satellite an order of magnitude more precise than all previous clocks flown for navigation purposes, multiple transmission frequencies with robust modulation and wide bandwidth, stable orbits avoiding Earth rotation resonances, the absolute calibration of satellite antennas plus onboard laser retroreflectors that allow the satellite orbits to be characterised down to within centimetres.”