Other Satellite Navigation Systems - Understanding GPS: Principles and Applications - page 596

Kazakhstan. However, early in the program, the Soviets launched ballast payloads,
instead of real satellites, to save production costs while the system was under
development.
At a meeting of the Special Committee on Future Air Navigation Systems
(FANS) of the ICAO in 1988, the USSR offered the world community free use of
GLONASS navigation signals. A similar offer was made at the 35th Session of the
IMO Subcommittee of Navigation Safety in the same year [1].
After the demise of the Soviet Union (SU), in 1990-1991, the Russians estab-
lished a test constellation of 10 to 12 satellites. Extensive testing of the system fol-
lowed this. As a result, in September 1993, Russian President Boris Yeltsin officially
proclaimed GLONASS to be an operational system, part of the Russian Armory and
the basis for the Russian Radionavigation Plan [2].
During the development, it became clear that GLONASS signals interfered with
radio astronomy observations in the 1,610.6-1,613.8-MHz band. The international
scientific community protested, and the Russians agreed to modify the future
GLONASS frequency plan in November 1993. Under the plan, the Russians
quickly ceased transmitting directly in the band, doubling up on navigation signal
frequency-channel assignments, and they promised to gradually move the
GLONASS signals out of the radio astronomy band as they depleted the stock of
older satellites and replenished the constellation with new satellites. At the time of
this writing, the Russians were continuing to follow through on their commitments
to this plan [1, 3].
In April 1994, the Russians initiated the first of seven launches to complete the
constellation. In December 1995, the Russians successfully launched the last set of
three satellites to complete the 24-satellite constellation. In February 1996, these
satellites were declared operational, and the constellation was fully populated for
the first and only time. However, a number of older satellites soon thereafter failed,
and the constellation quickly degraded. From 1996 through 2001, the Russians only
launched two sets of three satellites. This was insufficient to maintain the constella-
tion. The constellation degraded to six to eight satellites in 2001. To date, the con-
stellation has not been restored to full operational strength.
During the buildup, the government of Russia issued Decree 237 on March 7,
1995, which opened the GLONASS C/A code signals up to the civil use and guaran-
teed it would be available free of charge, affirming the Soviet 1988 statement. (Sec-
tion 11.1.9 contains signal characteristic descriptions.) The Russians also published
and made publicly available an Interface Control Document, which detailed the
structure of the GLONASS signals [4, 5].
Later, on February 18, 1999, the Russian president issued a decree 38-RP,
which declared GLONASS a dual-use system. This was followed by a decree on
March 29, 1999, opening GLONASS up for international cooperation. This
allowed the Russians to negotiate with the EU for possible inclusion of GLONASS
in the GALILEO program [6, 7].
The Russian Space Agency attempted to broker a deal with the Europeans on
incorporating GALILEO into the GLONASS program. Separately the Russians con-
ducted talks with China to fund GLONASS; however, neither effort appears to have
succeeded.