GIOVE-A laser ranging campaign successful

Oct 03, 2006
GIOVE-A laser ranging campaign successful
Artist's impression of GIOVE-A in orbit. Credits: ESA

Fourteen laser ranging stations participated in a campaign to track ESA's GIOVE-A satellite during the spring and summer of 2006, providing invaluable data for the characterisation of the satellite's on-board clock. The campaign was coordinated by the International Laser Ranging Service (ILRS) and the GIOVE Processing Centre at ESA-ESTEC.

GIOVE-A, developed by Surrey Satellite Technology Ltd (UK), was launched from Baikonur Cosmodrome on 28 December 2005 and placed into a medium Earth orbit with an altitude of 23 260 km. Carrying a payload consisting of rubidium clocks, signal generation units and a phase array of individual L-band antenna elements, GIOVE-A started broadcasting Galileo signals on 12 January, securing the frequencies allocated by the International Telecommunications Union for the Galileo system.

The performance characterisation of the on-board clocks is significantly enhanced by the use of Satellite Laser Ranging (SLR), a high precision technique for orbit determination that is independent of the navigation signal generation. The technique is based on a global network of stations that measure the round flight time of ultra short laser pulses to satellites equipped with Laser Retro Reflectors (LRR). Laser ranging provides instantaneous range measurements of millimetre-level precision which can be used to derive accurate orbit data.

GIOVE-A is equipped with a LRR having 76 corner cubes, manufactured by IPIE of Russia, which provides a return energy 40% higher than GPS reflectors. The use of SLR data allows a more robust orbit determination, and thus a more accurate clock characterisation. In addition, certain satellite properties relevant to navigation, such as the offset between the centre of mass and the centre of the navigational phase centre, can be verified and calibrated.

The International Laser Ranging Service (ILRS) has agreed to support the GIOVE-A mission by providing SLR data during several tracking campaigns coordinated with the GIOVE Processing Centre at ESA-ESTEC. The first of these tracking campaigns took place between 22 May and 24 July 2006, with the participation of 14 SLR stations, distributed globally. In addition to confirming the good health of the LRR on GIOVE-A after launch, the SLR data has been essential for a health check and a preliminary performance characterisation of the on-board rubidium clocks.

With GIOVE-A, ESA is validating the critical new technologies needed for the Galileo system and preparing for the next phase of In-Orbit Validation (IOV). For this next step, four satellites will be launched. On completion of IOV, the four satellites will become the initial components of the operational Galileo constellation. Galileo is a joint initiative of the European Commission and the European Space Agency. It is the first satellite positioning and navigation system specifically designed for civilian purposes and will offer state-of-the-art services with outstanding performance and guaranteed accuracy, integrity, continuity and availability.

Source: ESA

Explore further: Europe resumes Galileo satnav deployment (Update)

add to favorites email to friend print save as pdf

Related Stories

Future US Navy: Robotic sub-hunters, deepsea pods

3 hours ago

The robotic revolution that transformed warfare in the skies will soon extend to the deep sea, with underwater spy "satellites," drone-launching pods on the ocean floor and unmanned ships hunting submarines.

Europe resumes Galileo satnav deployment (Update)

14 hours ago

Europe resumed deployment of its beleaguered Galileo satnav programme on Friday, launching a pair of satellites seven months after a rocket malfunction sent two multi-million euro orbiters awry.

Italian olive tree disease stumps EU

15 hours ago

EU member states are divided on how to stop the spread of a disease affecting olive trees in Italy that could result in around a million being cut down, officials said Friday.

Festo has BionicANTs communicating by the rules for tasks

15 hours ago

Germany-based automation company Festo, focused on technologies for tasks, turns to nature for inspiration, trying to take the cues from how nature performs tasks so efficiently. "Whether it's energy efficiency, ...

Recommended for you

More evidence for groundwater on Mars

19 hours ago

Monica Pondrelli and colleagues investigated the Equatorial Layered Deposits (ELDs) of Arabia Terra in Firsoff crater area, Mars, to understand their formation and potential habitability. On the plateau, ...

Scuttling satellites to save space

Mar 27, 2015

It takes a lot of ingenuity – not to mention a massive quantity of sheer force – to get satellites into orbit. Now space engineers are applying comparable ingenuity to the challenge of getting their missions ...

A new look at the sun's magnetic field

Mar 27, 2015

Sunspots, bursts of radiation and violent eruptions are signs that our sun is permanently active. Researchers have long known that this activity varies in a cycle of around eleven years' duration. Even if ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.