Talk:GLONASS

New news

http://www.mosnews.com/news/2005/12/25/glonass.shtml

Russia is enlarging its orbital grouping with three spacecraft of the Global Navigation Satellite System (GLONASS) at one go, Russian Space Agency Roskosmos said Sunday.

Russia launched a Proton-K carrier rocket with three satellites from the Baikonur space center in Kazakhstan at 8:07 a.m. Moscow time (5:07 a.m. GMT), RIA Novosti reported.

“The trio includes one spacecraft of an old make (three-year service life) and two satellites of the new modification GLONASS-M with better specifications and a service life of seven years,” press service head of the Space Troops Alexei Kuznetsov told Itar Tass.

According to Roskosmos, the carrier rocket was launched in accordance with the schedule.

Under the federal space program approved by the government, the GLONASS satellite group will be expanded to at least 18 satellites by 2007. Currently, the system includes 14 satellites in orbit.

The main purpose of the GLONASS network is to provide global positioning services for various military and civilian customers. GLONASS satellites incessantly transmit information on exact coordinates of air, sea, land and space objects.

18 satellites, not 12

http://lenta.ru/news/2006/12/22/glonass/ states that Russia was planning to launch 3 new GLONASS satellites, which would bring the total number up to 18. Those 3 satellites were successfully launched on December 25: http://www.lenta.ru/news/2006/12/26/glonass/. Therefore, today (2006-12-29) there are, presumably, 18 GLONASS satellites in orbit. So why does the article say there are 12? Are there any verifiable sources for that number? — Preceding unsigned comment added by Tetromino (talk • contribs)

Yes, this needs to be clarified and corrected. I wanted to do so previously, but there is some confusion on which number to include. This Wiki article currently says "12 are in operation". Official website of GLONASS presents the table of satellites currently in orbit, according to which, 11 are currently in operation, while 5 are "temporarily switched off". Three recently launched satellites are not included in the table at all yet. So, how should we rephrase the sentence? Maybe we should say something like "19 are in orbit with 11 of them in operation"? Cmapm 12:28, 29 December 2006 (UTC)[reply]

You are right, only 11 are in operation. And according to http://www.roscosmos.ru/NewsDoSele.asp?NEWSID=2021, the Russian flight control center "took control of" the 3 new satellites on December 26. So I am assuming that they are adjusting the orbit and running various tests, and that the 3 new satellites are not yet a part of the GLONASS cluster. So I might say something like "On December 29, 2006, there were 16 satellites in the GLONASS system, of which 11 were in operation. An additional 3 satellites were launched on December 25, but they have not yet been activated."

Also, with 11 satellites active, the 94% availability is not correct. According to http://www.glonass-ianc.rsa.ru/pls/htmldb/f?p=202:24:7305574700466879622::NO::: (for some reason there is no English version of this page), GLONASS coverage is 52% of Russian territory and 40% of the globe. (Although, judging by the map, the populated parts of Russia have nearly perfect coverage.) Tetromino 15:00, 29 December 2006 (UTC)[reply]

Near perfect coverage? Looking at the Google translation, "Availability is calculated on the basis of this anthology for daily interval as a percentage of time during which the condition PDOP <=6" most of the world is in the dark red 25% - 50% section, which I take to mean that between 25%-50% of the time the signal is acceptable. "A PDOP of 4 or below gives excellent positions. A PDOP between 5 and 8 is acceptable."[1] The way I see the image, the the lighter the color the better, white = 100% of the time PDOP <=6. Of course the Google translation is a Beta, so it might be wrong. --Dual Freq 15:27, 29 December 2006 (UTC)[reply]

Interesting. At first I assumed that black is better (since low PDOP values are better, and since I imagine they would want good coverage in the North Caucasus). But maybe the color scale doesn't have anything to do with PDOP and directly represents coverage instead; in that case white would be better. Without a properly labeled scale, it's hard to tell what the map really represents. Tetromino 15:41, 29 December 2006 (UTC)[reply]

I've introduced respective changes, adding, that global availability is 40.0%. Cmapm 17:50, 29 December 2006 (UTC)[reply]

If I'm reading it right, it's even lower (29% Global, 32% Russia). I always thought that GLONASS was a bit better than this. Zetetic Apparatchik 11:37, 31 December 2006 (UTC)[reply]