Europe’s latest navigation satellites, launched last December, have been officially commissioned into the Galileo constellation, and are now broadcasting working navigation signals since 22 April.

Galileos 11 and 12 were launched together on a Soyuz rocket from Europe’s Spaceport in French Guiana on 17 December. The satellites’ navigation payloads were submitted to a gamut of tests, centred on ESA’s Redu centre in Belgium, which possesses a 20 m-diameter antenna to analyse the satellites’ signals in great detail.

For users to navigate with metre-level accuracy, Galileo must keep extremely accurate time. Because light travels at a fixed speed, just under 30 cm every billionth of a second, the time it takes for Galileo signals to reach a user’s receiver on the ground can be converted into distance. All the receiver has to do is multiply the travel time by the speed of light, pinpointing its location from at least four satellites. Read more…

Galileos arriving in French Guiana

The next Galileo launch campaign has begun with the arrival of the latest pair of navigation satellites at Europe’s Spaceport in French Guiana.

Their arrival is the start of a busy schedule that will culminate with their launch on a Soyuz rocket on 17 December, the third Galileo launch of the year.

Galileos 11 and 12 touched down at a rain-soaked Cayenne-Félix Eboué Airport on Friday 31 October at 1300 local time.

The satellites were unloaded from their Boeing 747 aircraft, still in their humming air-conditioned containers, straight onto waiting lorries for the last leg of their trip to the Spaceport. Read more…