Improving the accuracy of satellite navigation systems

Paris, (PresseBox) - Einstein's general theory of relativity, which deals with gravity, could be used to improve global navigation systems in the future. ESA's Advanced Concepts Team has collaborated with the University of Ljubljana to research this possibility.

Present navigation satellite systems, such as Galileo and GPS, employ Newtonian trigonometry to determine positions, using Earth stations as reference points. This approach would perform ideally if all the satellites and the receiver were at rest and far from Earth.

These are accounted for by introducing relativistic corrections to the Newtonian theory. For a ground user, these corrections can be as large as 12 km after one day.

Changing the paradigm

A simple way to avoid having to deal with the defects of Newtonian theory is to change the paradigm. Instead of modelling the system in a Newtonian framework and adding relativistic corrections, the positioning system could be modelled directly in general relativity.

Drawing inspiration from a paper published by Bartolomé Coll of Systèmes de Référence Temps-Espace at the Observatoire de Paris, a study was conducted to introduce such relativistic coordinates for the definition of a global reference frame that can be used for positioning and navigation.

A local Schwarzschild frame was designed, based on the clock signals originating from four satellites. Algorithms to read the user's local Schwarzschild coordinates from the four satellites signals were developed, implemented and tested.

The new reference frame is based on the dynamics of the satellites instead of relying on the location of terrestrial ground stations. If the constellation of satellites were to be equipped with intersatellite communications, then each satellite could be a user of its own positioning system.

The first results promise an increase in the accuracy and stability by using the new reference frame. The question whether it can avoid the need for terrestrial reference frames is still under study.

Future applications

A workshop on Relativistic Positioning Systems was organised at ESTEC in April, to present the results of ESA's studies and the work of other research groups in Europe. The new approach based on our very fundamental understanding of spacetime could lead to several new applications, including:

-A highly stable and accurate reference system in space, which could be used for space science and highprecision orbitography;

-The definition of a galactic reference frame for interplanetary navigation, using pulsars as clocks.

The results complement other studies performed by ESA that show how intersatellite communication could reduce the ground infrastructure and operating costs of a navsat system while increasing its reliability.

Press releases you might also be interested in

Weitere Informationen zum Thema "Luft- / Raumfahrt":

Neue Geschäftsmodelle auf Datenbasis

Ba­sie­rend auf Lauf­zeit­da­ten von Kom­po­nen­ten und Ma­schi­nen kön­nen ver­schie­de­ne Ana­ly­sen vor­ge­nom­men wer­den (Stör­un­gen, Still­stän­de oder Zu­stän­de). Die Aus­wer­tun­gen las­sen sich dann zur Ent­wick­lung neu­er da­ten­ba­sier­ter Di­enst­leis­tun­gen nut­zen.


Subscribe for news

The subscribtion service of the PresseBox informs you about press information of a certain topic by your choice at a choosen time. Please enter your email address to receive the email with the press releases.

An error occurred!

Thank you! You will receive a confirmation email within a few minutes.

I want to subscribe to the gratis press mail and have read and accepted the conditions.