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Text B. GLONASS

The days of the cold war may have passed, but Russia and the United States are in the midst of another battle - this one a technological fight over the United States monopoly on satellite navigation. Nor is Russia the only country trying to break the American monopoly on navigation technology. China has already sent up satellites to create its own system, called Baidu after the Chinese word forthe Big Dipper¹. And the European Union has also begun developing a rival system, Galileo, although work has been halted because of doubts among the private contractors over its potential for profits.

GLONASS is a radio-based satellite navigation system, developed by the former Soviet Union and now operated for the Russian government by the Russian Space Forces. Development on the GLONASS began in 1976. The constellation was completed in 1995, but the system rapidly fell into disrepair with the collapse of the Russian economy. Beginning in 2001, Russia committed to restoring the system by 2011, and in recent years has diversified, introducing the Indian government as a partner, and accelerated the program with a goal of global coverage by 2009 A fully functional GLONASS constellation consists of 24 satellites, with 21 operating and three on-orbitspares^[1], deployed in three orbital planes. A characteristic of the GLONASS constellation is that any given satellite only passes over the exact same spot on the Earth every eighth sidereal day. However, as each orbit plane contains eight satellites, a satellite will pass the same place every sidereal day. For comparison, each GPS satellite passes over the same spot once every sidereal day.

There were three generations of the satellites. The true first generation of Uragan satellites were all 3-axis^[2] stabilized vehicles, generally weighing 1,250-kg.

These spacecraft demonstrated a 16-month average operational lifetime. The second generation of satellites, known as Uragan-M (also called GLONASS-M), possess a substantially increased lifetime of seven years and weigh slightly more - 1,480 kg. The latest designed generation of Uragan-K (GLONASS-K) spacecraft are the third generation of satellites. These satellites are designed with a lifetime of 10 to 12 years, a reduced weight of only 750 kg, and offer an additionalL-Band⁴ navigational signal. As with the previous satellites, these are 3-axis stabilized,nadir⁵ pointing with dual solar arrays.

By May 2007 the system remains partially operational. There were 11 satellites. In recent years, Russia has kept the satellite orbits optimized for navigating in Chechnya, increasing signal coverage there at the cost of degrading coverage in the rest of the world. GLONASS availability in Russia was 45.3% and average availability for the whole Earth was down to 30.5%, with significant areas of less than 25% availability. Meaning that, at any given time of the day in Russia, there is a 45.3% likelihood that a position fix can be calculated.

The Russian system is also calculated to send ripples through the fast-expanding industry for consumer navigation devices by promising a slight technical advantage over G.P.S. alone. Devices receiving signals from both systems would presumably be more reliable. "The network must be impeccable, better than G.P.S., and cheaper if we want clients to choose Glonass," Mr. Putin said at a Russian government meeting on the system.

Notes (B):

1) ¹the Big Dipper - Большая Медведица (the US and Canadian name for

the Plough (constellation).

2) ²spare- запасной (in reserve for use when needed).

3) ³axis - ось (a real or imaginary line about which a body, such as an

aircraft, can rotate or about which an object, form, composition, or geometrical

construction is symmetrical).

4) ⁴ L-Band - RF range 390 - 1550 MHz

5) ⁵nadir - надир (the point on the celestial sphere directly below an

observer and diametrically opposite the zenith).

4.16 Make up 10 questions to the text using the following constructions:

What is the (nature, difference, process, role, importance, etc.) of…?

What is referred to as….?

What is used as…?

Where do we use. …?

What function do the ... play?

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