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system infrastructure/technology

September 26, 2007

GLONASS has “preliminary approval” to transmit CDMA GLONASS signals at L1, L5

GLONASS has gotten “preliminary approval” to add code division multiple access (CDMA) signals to future satellites.

Since its initiation in the early 1980s, the Russian GNSS system has employed frequency division multiple access (FDMA) techniques in which the same code is used for the signals broadcast by the system, with individual spacecraft being distinguished from one another by a specific frequency allocation. Russia would almost certainly continue broadcasting FDMA signals on existing frequencies.

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By Glen Gibbons
September 15, 2007

USAF evolves GPS architecture with $800 million upgrade to ground control segment

On September 14, Air Force crews at Schriever AFB, Colorado, completed the initial phase of an $800 million upgrade to the GPS operational control segment.

Operators in the 2nd Space Operations Squadron (2SOPS) of the USAF 50th Space Wing migrated control of the GPS satellite constellation and ground monitoring facilities from a 1970s-era mainframe computer to a distributed IT infrastructure with advanced automated features. The 50th Space Wing, through the 2nd SOPS, performs the satellite command and control mission for the Global Positioning System.

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By Inside GNSS
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September 9, 2007

It’s MBOC for common Galileo-GPS civil signal

The United States and the European Union (EU) have agreed to use the multiplexed binary offset carrier (MBOC) for a common GPS-Galileo signal for civilian use. In the future, this will enable combined GNSS receivers to track the GPS and Galileo signals with higher accuracy, even in challenging environments that include multipath, noise, and interference.

These signals will be implemented on the Galileo Open Service and the GPS IIIA new L1 civil signal known as L1C.

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By Inside GNSS

Proton launch failure raises questions about timeline for completing GLONASS constellation

The September 6 crash of a Russian Proton-M rocket carrying a Japanese telecommunications satellite (JCSAT 11) has injected an element of uncertainty into plans for completing the GLONASS constellation.

Russia’s Baikonur cosmodrome automatically suspended all Proton rocket flights, pending an investigation, after the failure of the rocket, which crashed in the steppes of Kazakhstan just over two minutes after lift-off. Russia rents the space facility from Kazakhstan, a former republic in the USSR.

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By Inside GNSS
August 30, 2007

Sunspots Blank GNSS Receivers

Researchers at Cornell University recently released their analysis of the effects of solar radio bursts (SRBs) during a solar flare last December that produced “unprecedented” fades in received GPS signal power at L1 and L2 over an extended period.

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By Inside GNSS
July 2, 2007

U.S. Air Force Releases GPS Block IIIA Satellite RFP

After several false starts in the previous months and a multi-year delay in the overall GPS III architecture development, the GPS Wing (formerly the GPS Joint Program Office) announced on July 12 the release of a request for proposal for the development and production of the GPS Block IIIA satellites.

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By Inside GNSS
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May 1, 2007

Galileo’s Plan B (and C)

A sea change appears to be taking place in Europe’s Galileo program as its political masters prepare to transform the struggling public-private partnership (PPP) into a more traditional institutional program wholly sponsored by the public sector.

That would move an additional €2.4 to €3 billion onto the public tax burden, but it might also represent the quickest route to completion of the GNSS project backed by the European Union (EU) and the European Space Agency (ESA).

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By Inside GNSS

GPS: Launches of Satellites and Institutional Initiatives

Successful launch of the second modernized Block IIR satellite, IIR-15(M2), on September 25 and scheduling of another IIR-M launch on November 14 underlines recent progress in the GPS program.

IIR-15(M2), also identified by its space vehicle number (SVN58) and pseudorandom code number (PRN31), will be placed into orbital plane A, slot 2. The U.S. Air Force has designated the satellite to be launched in November as GPS IIR-16/M3, PRN15/SVN55.

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By Inside GNSS
September 1, 2006

USAF Announces More IIF Delay

The GPS Block IIF program continues to lose ground, with first launch of a satellite now projected as no sooner than May 2008 and as late as January 2009 in a “worst case,” scenario, according to the U.S. Air Force. Program costs are also increasing.

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By Inside GNSS
May 1, 2006

GPS III, Block IIF Programs Hit New Delays

The GPS program appears to be struggling on several fronts recently.

GPS III, the next-generation modernization project for the space and ground segments, is facing renewed uncertainty and possible schedule delays. At the same time, anticipated first launch of the follow-on block of satellites (Block IIF) with the new civil L5 signal has been postponed.

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By Inside GNSS
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