SX5 - Scientific Service Support Based on Galileo E5 Receivers





01.02.2010- 31.01.2012






Met Office 

 Projectleader at the Institute

Torben Schüler

Scientific service support based on Galileo E5 receivers

SX5 is a project conducted by a consortium of 6 partners. It is funded by the European Union within the 7th Framework Programme and supervised by the GNSS Supervisory Authority GSA. Its main topic is the scientific exploitation of the Galileo E5 signal.

An E5 receiver and a scientific software application prototype will be developed and the application to selected scenarios such as atmosphere monitoring, deformation analysis and precise orbit determination will be tested.

The scientific community has been actively and intensively making use of GPS since the very start of GNSS. GPS has undoubtedly revolutionised certain aspects, such as surveying techniques, and has enabled scientists to realise applications which had not been feasible before. The current paradigm in the scientific community, however, is that accurate results essentially require two-frequency receivers with a preferred use of carrier phase measurements
for precise positioning applications.

This way of thinking is primarily motivated by the fact that ionospheric delays can be eliminated by using at least two or more frequencies, and carrier phase measurements are less corrupted by multipath effects than range measurements. However, Galileo will offer one dedicated signal that is superior to all other signals which will be available in space: the broadband signal E5.

This signal will feature an ultimately low-range noise in the centimetre range,
as well as the lowest multipath error impact ever observed in the history of
satellite navigation, which can be as low as a couple of centimetres in benign
environments (and smaller by far than the multipath errors on every signal in all other environments, too).

The drastically increased range precision of the Galileo E5 signal will allow for combined ‘code-and-carrier positioning’ with high accuracy – but only a single-frequency Galileo receiver will be needed in future rather than a (more expensive) multi-frequency device. Carrier phase and range measurements will
almost become equitable types of observables in terms of accuracy (up to now, range measurements are very much of inferior quality when compared to the carrier phases). As for a dual-frequency GPS-receiver, such a single-frequency system will be able to eliminate the ionospheric propagation error. The central objective of SX5 will be to develop a software application for precise positioning
based on an E5 Galileo receiver primarily targeting scientific users. Consequently, a full exploitation of the Galileo E5 signal allowing the realisation of applications, which previously required dual-frequency receivers, can be  achieved.

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