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  European Galileo satellite-navigation network

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Author Topic:   European Galileo satellite-navigation network
SkyMan1958
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Posts: 470
From: CA.
Registered: Jan 2011

posted 02-02-2012 11:26 PM     Click Here to See the Profile for SkyMan1958   Click Here to Email SkyMan1958     Edit/Delete Message   Reply w/Quote
According to BBC News, the European commission has issued a contract to increase Europe's GPS constellation from 14 satellites to 22. It is expected that eventually the constellation will grow to 30 satellites.

The eight new satellites will be built by a consortium of OHB System (a German Co.) and SSTL (a British Co.).

Galileo's next-generation technologies are designed to provide users with quicker, more reliable fixes, enabling them to locate their positions with an error of one metre, compared with the current GPS error of several metres.

SkyMan1958
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Posts: 470
From: CA.
Registered: Jan 2011

posted 10-15-2012 01:10 PM     Click Here to See the Profile for SkyMan1958   Click Here to Email SkyMan1958     Edit/Delete Message   Reply w/Quote
The third and fourth satellites in Europe's version of GPS (Galileo) were launched on a Soyuz rocket from French Guiana, BBC News reported.
With four satellites now in orbit — the first and second spacecraft were launched in 2011 — it becomes possible to test Galileo end-to-end.

That is because a minimum of four satellites are required in the sky for a smartphone or vehicle to use their signals to calculate a positional fix.

Engineers can now run an intensive programme to validate every aspect of Galileo's design, including its all-important ground infrastructure which will monitor and control the satellites.

It is expected that it will be about 2015 before there are enough satellites in orbit for the system to show its true capability.

The full deployment of the system, 27 operational satellites and three spares, will take most of the decade.

Robert Pearlman
Editor

Posts: 30278
From: Houston, TX
Registered: Nov 1999

posted 08-23-2014 10:34 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
On Aug. 22, 2014, Arianespace launched two operational satellites in the Galileo constellation. The launch took place at 8:27 a.m. EDT (1227 GMT) from the Guiana Space Center, Europe's Spaceport.

The two satellites, launched on a Soyuz rocket, were to be placed into a circular Medium Earth Orbit (MEO), at an altitude of 23,522 kilometers. They were to be inclined to the Earth's equator by about 55 degrees.

Following the launch however, it was determined the satellites had been released into the wrong orbit, Arianespace stated.

Galileo satellites orbital injection anomaly

Complementary observations gathered after separation of the Galileo FOC M1 satellites on Soyuz VS09 have highlighted a discrepancy between targeted and reached orbit.

Investigations are underway. More information will be provided after a first flight data analysis to be completed on August 23, 2014.

According to the European Space Agency, both satellites have been acquired and are safely controlled and operated from ESA's Operations Center in Germany.

Robert Pearlman
Editor

Posts: 30278
From: Houston, TX
Registered: Nov 1999

posted 08-23-2014 12:33 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
With regards to the original four Galileo satellites in orbit, one had to be shut down in May following a sudden loss of power, Space News reports.
Javier Benedicto, ESA’s Galileo program manager, said during the briefing that Galileo teams have examined more than 40 different failure scenarios in the search for a cause, with no firm results thus far. The investigation has included asking satellite component builders to reproduce certain components for testing. It has also included tilting the affected satellite to assess radiation pattern changes on the spacecraft’s L-band antenna, he said.

Benedicto said the investigating team concluded that maintaining high broadcast power might exacerbate the problem, so all four satellites’ output was dropped by 1.5 decibels.

The May power loss was on the satellite named FM-4. An apparently unrelated power drop occurred in mid-2013 on the FM-3 satellite, Benedicto said, resulting in a 2-decibel decrease in power on one of the satellite’s signals.

The investigation into that early incident is also ongoing, Benedicto said. No root cause has been found, and the inquiry has now been merged with the search for a cause for the FM-4 failure.

mikej
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Posts: 414
From: Germantown, WI USA
Registered: Jan 2004

posted 08-29-2014 09:44 AM     Click Here to See the Profile for mikej   Click Here to Email mikej     Edit/Delete Message   Reply w/Quote
Galileo satellites incident likely result of software errors, RIA Novosti reports.
The failure of the European Union’s Galileo satellites to reach their intended orbital position was likely caused by software errors in the Fregat-MT rocket’s upper-stage, Russian newspaper Izvestia reported Thursday.

"The nonstandard operation of the integrated management system was likely caused by an error in the embedded software. As a result, the upper stage received an incorrect flight assignment, and, operating in full accordance with the embedded software, it has delivered the units to the wrong destination," an unnamed source from Russian space Agency Roscosmos was quoted as saying by the newspaper.

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