Dawn of a New Era: First GLONASS CDMA Signal Tracked from Moscow (Updated)

Dawn of a New Era: First GLONASS CDMA Signal Tracked from Moscow (Updated)

http://www.gpsworld.com/gnss-system/glonass/news/dawn-a-new-era-first-glonass-cdma-signal-tracked-moscow-updated-11488

On Tue, 12 Apr 2011 21:01:10 -0500, Sam Wormley wrote:


What is the significance of this? I haven't followed recent
Glonass developments.

Hans-Georg

On 4/13/11 2:11 AM, Hans-Georg Michna wrote:
http://www.gpsworld.com/gnss-system/glonass/news/dawn-a-new-era-first-glonass-cdma-signal-tracked-moscow-updated-11488

GLONASS CDMA Signals use "carriers" of the same frequency making them
more compatible with those of GPS and Galileo GNSSs.

Addition of CDMA to the GLONASS signal structure has been a long time
coming, with a long time yet to go before a fully operational CDMA
constellation. Nevertheless, this first CDMA broadcast by a GLONASS
satellite is still a milestone.

http://www.pnt.gov/public/docs/2004/russia.shtml

"The United States and the Russian Federation . . . intend to work
together to the maximum extent practicable to maintain radio frequency
compatibility in spectrum use between each other's satellite-based
navigation and timing signals. Both sides will work together to the
maximum extent practicable to maintain compatibility and promote
interoperability of GPS and GLONASS for civil user benefits
worldwide."

http://www.pnt.gov/public/docs/2006/russia.shtml

"Both sides noted that concerning the question of the use FDMA and
CDMA significant progress was made in understanding the benefit to the
user community of using a common approach. The Russian side noted that
a decision in this regard would be made by the end of 2007. "

http://www.insidegnss.com/node/648

"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=92s second-oldest global satellite navigation system apart
from GPS and other systems under development.

. . . Use of FDMA GNSS techniques, in which the same code is used to
broadcast navigation signals on different frequencies, and the
placement of civil GLONASS transmissions on frequencies between
1598.0625 and 1606.5 MHz well above the GPS L1 band, have complicated
the design of combined GLONASS/GPS receivers, particularly low-cost
equipment for mass market applications.

. . . Adding the CDMA signals reflects the Russian government=92s
mandate to increase compatibility and interoperability with open
services provided by other GNSS systems, driven in part by a desire to
accelerate adoption of GLONASS in consumer products. Promoting
development of civil GNSS chips by Russian companies is among the
goals of the GLONASS directive."

Springer and Dach plot PDOP for GPS-only and GPS + GLONASS here:

http://www.gpsworld.com/gnss-system/glonass/innovation-gps-glonass-and-more=
-10007?page_id=3D2

Alan Cameron summarizes the GLONASS presentation at the annual CGSIC
meeting last September:

http://www.gpsworld.com/gnss-system/the-system-glonass-forecast-bright-and-=
plentiful-10580

The presentation slides:

http://www.navcen.uscg.gov/pdf/cgsicMeetings/50/%5B3%5DCGSIC_GLONASS_Revniv=
ykh_20_09_2010.pdf

The 12 April 2011 GPS World story repeats a Javad press release:

http://www.javad.com/jgnss/javad/news/pr20110408.html

Septentrio has also announced successful tracking, and others may
follow:

http://www.insidegnss.com/node/2563

Thanks for the good information!

So more GPS-like satellites. That can only be a good thing,
particularly if the GPS receiver manufacturers update the
receivers we use, so they can utilize all three systems, GPS,
GLONASS, and GALILEO. More precision, higher reliability, better
functioning between buildings in cities, I guess.

Hans-Georg