Introduction - Understanding GPS: Principles and Applications - page 8

GALILEO is scheduled to be operational in 2008. Chapter 10 describes the
GALILEO system, including satellite signal characteristics.

1.6 Russian GLONASS System

The Global Navigation Satellite System (GLONASS) is the Russian counterpart to
GPS. It consists of a constellation of satellites in medium Earth orbit (MEO), a
ground control segment, and user equipment, and it is described in detail in Section
11.1. At the time of this writing, GLONASS was being revamped and the system was
undergoing an extensive modernization effort. The constellation had decreased to 7
satellites in 1991 but is currently at 14 satellites. The GLONASS program goals are
to have 18 satellites in orbit in 2007 and 24 satellites in the 2010-2011 time frame.
A new civil signal has been on orbit since 2003. This signal has been broadcast from
two modernized satellites referred to as the GLONASS-M. These two satellites are
reported to be test flight satellites. There are plans to launch a total of 8
GLONASS-M satellites. The follow-on satellite to the GLONASS-M is the
GLONASS-K, which will broadcast all legacy signals plus a third civil frequency for
SOL applications. The GLONASS-K class is scheduled for launch in 2008 [13].
As part of the modernization program, satellite reliability is being increased in
both the GLONASS-M and GLONASS-K designs. Furthermore, the GLONASS-K is
being designed to broadcast integrity data and wide area differential corrections [13].
Figures 1.5 and 1.6 depict the GLONASS-M and GLONASS-K satellites, respectively.
The Russian government has stated that, like GPS, GLONASS is a dual-use sys-
tem and that there will be no direct user fees for civil users. The Russians are work-
ing with the EU and the United States to achieve compatibility between GLONASS
and GALILEO, and GLONASS and GPS, respectively [13]. As in the case with

Figure 1.5 GLONASS-M satellite.