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system interoperability

May 12, 2008

Galileo’s GIOVE -B Spacecraft Transmits Signals

A screen in the Galileo control room displays the spectra of signals received from GIOVE-B shortly after the spacecraft began transmitting navigation signals. ESA photo.

Europe’s second Galileo In-Orbit Validation Element (GIOVE-B) satellite began transmitting navigation signals on May 7, including the common GPS-Galileo civil signal MBOC (multiplexed binary offset carrier).

Built under a cooperation between the European Space Agency (ESA) and European Union (EU), GIOVE-B was launched April 27 from the Baikonur cosmodrome in Kazakhstan. The MBOC signal design will be used by the future GPS L1C broadcasts as well as the Galileo Open Service in accordance with an agreement drawn up in July 2007 between the EU and the United States.

Locked to an on-board passive hydrogen maser clock, the GIOVE-B signals will help improve positioning accuracy in challenging environments with multipath and interference as well as better penetration for indoor navigation.

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By Inside GNSS
April 28, 2008

Russia Approves CDMA Signals for GLONASS, Discussing Common Signal Design

Nearly 30 years after the first launch of a GLONASS spacecraft, Russia is moving to add code division multiple access (CDMA) signals to the frequency division multiple access (FDMA) format that has set the world’s second-oldest global satellite navigation system apart from GPS and other systems under development.

A February 15, 2008, government decree on new GLONASS requirements calls for open CDMA signals with a binary offset carrier or BOC (2,2) signal structure centered at 1575.42 MHz and a BOC (4,4) signal centered at 1176.45 MHz — essentially corresponding to the center points of GPS signals at the L1 and L5 frequencies and nearby Galileo and Compass signals.

An additional GLONASS FDMA signal will be located at L3 frequencies (1197.648–1212.255 MHz), just below the GPS M-code at L2.

Russia will implement the new signals on the next-generation GLONASS-K satellites, with the first launch currently expected in late 2010 with flight testing the following year.

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By Glen Gibbons
March 2, 2008

China’s Compass/Beidou: Back-Track or Dual Track?

A recent presentation on Compass/Beidou that appeared to reflect a step back from China’s GNSS program more likely represented a step sideways — and an implicit acknowledgment of the complex political and technical elements involved in such an enterprise.

In February 20 remarks at the Munich Satellite Navigation Summit in Germany, Jing Guifei, a project manager at the National Remote Sensing Center of China (NRSCC), seemed to play down the global aspects of Compass — or Beidou 2 — while underlining near-term efforts to implement a regional capability for the system.

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By Glen Gibbons
February 22, 2008

GLONASS CDMA Signals Near Approval

Russia appears ready to add code division multiple access (CDMA) signals to its frequency division multiple access (FDMA) GLONASS system.

A final decision is expected next week, according to Sergey Revnivykh, deputy head of the Russian GNSS Mission Control Center, in a February 20 presentation to the Munich Satellite Navigation Conference in Germany. Under the plan, CDMA signals would be introduced at L1 and L5 frequencies near GPS and Galileo signals, beginning with the GLONASS-K generation of satellites that will launch in 2010.

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By Inside GNSS
December 10, 2007

China to Reveal Compass Plans ‘Soon’

Liao Xiaohan, Deputy Director-General of High & New Technology Development and Industrialization, MOST

China will release details of its Compass (or Beidou 2) program “soon,” including an Interface Control Document (ICD) for the GNSS system’s open civil service and a launch schedule for additional satellites, according to representatives of the China Satellite Navigation Engineering Center speaking at the Shanghai Navigation Forum (NaviForum) in Shanghai on Thursday and Friday (December 6-7).

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By Glen Gibbons
October 18, 2007

Get ready for the 2008 Toulouse Space Show! ENC-GNSS, EFTF 08, and more . . .

ESA/CNES launcher at Toulouse Space Center

Next April’s Toulouse Space Show will provide a good deal of company for the European Navigation Conference (ENC-GNSS 2008).

In addition to the annual European Frequency and Time Forum (EFTF 08), which joined ENC-GNSS 2007 this year at TimeNav ’07 in Geneva, Switzerland, events include a Space Applications symposium sponsored by the French space agency CNES, a commercial exhibition, and associated events for the general public, students, and young people, to promote the value of space applications in daily life.

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By Glen Gibbons
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 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

Galileo: Coping with Change, China, and Challenges

The 14-year (and counting) history of Europe’s Galileo program has always made for a complex story line.

And it’s not getting any simpler.

Among the latest complications: the transition of responsibilities from the Galileo Joint Undertaking (GJU) to a new GNSS Supervisory Authority (GSA, also referred to as the Galileo Supervisory Authority), further extension of negotiations over a long-term concession contract to operate Galileo, and growing pressure from commercial companies to allow them to sell Galileo technology that they have developed or want to develop.

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By Inside GNSS
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