Introduction - Understanding GPS: Principles and Applications - page 18

E-911 are presented. Extensive treatment of network assistance techniques, perfor-
mance, and emerging standards is presented. This includes environment character-
ization in terms of median signal attenuation for rural, suburban, and urban areas.
Chapter 10 is dedicated to GALILEO. An overview of the system services is pre-
sented, followed by a detailed technical description of the transmitted satellite sig-
nals. Interoperability factors are considered next. The GALILEO system
architecture is put forth with discussions on constellation configuration, satellite
design, and launch vehicle description. Extensive treatment of the downlink satellite
signal structure, ground segment architecture, interfaces, and processing is pro-
vided. This processing discussion covers clock and ephemeris predictions as well as
integrity determination. The key design drivers for integrity determination and dis-
semination are highlighted. In addition to providing the navigation service,
GALILEO will also contribute to the international search and rescue (SAR) architec-
ture and its associated provided services. It is planned to provide a SAR payload on
each GALILEO satellite, which will be backward compatible with the present
COSPAS/SARSAT system. (The COSPAS/SARSAT system is the international
satellite system for search and rescue [24].)
Chapter 11 contains descriptions of the Russian GLONASS, Chinese BeiDou,
and Japanese QZSS satellite systems. An overview of the Russian GLONASS system
is first presented, accompanied with significant historical facts. The constellation
and associated orbital plane characteristics are then discussed. This is followed by a
description of the ground control/monitoring network and current and planned
spacecraft designs. The GLONASS coordinate system, Earth model, and time refer-
ence are also presented. GLONASS satellite signal characteristics are discussed. Sys-
tem performance in terms of accuracy and availability is covered. Elaboration is
provided on intended GLONASS developments that will improve all system
segments. Differential services are also presented.
The BeiDou program is discussed in Section 11.2. The history of the program is
briefly described. Constellation and orbit attributes are provided. These are fol-
lowed by spacecraft and RDSS service descriptions. User equipment classes and
types are put forth. These include general user terminals such as an emergency
reporting terminal that makes emergency reports to police and a general communi-
cations user terminal used for two-way text message correspondence. All classes of
user terminals provide a real-time RDSS navigation service. The system architecture
is described, followed by an overview of the five different types of BeiDou services.
System coverage is put forth next. Future developments including BeiDou SBAS and
BeiDou-2 are discussed.
At the time of this writing, the Japanese QZSS program was under development.
When completed, QZSS will provide GPS augmentation and mobile satellite com-
munications to Japan and its neighboring regions. The constellation, orbits, and sat-
ellite types have not been selected. The program goal is to address the shortfalls in
GPS visibility in urban canyons and mountainous terrain, which, the Japanese
assess, is a problem in 80% of the country. Concepts of spacecraft design and pro-
posed orbital plane design are described. This is followed by an overview of the
QZSS geodetic and time reference systems. Anticipated system coverage and
accuracy performance complete the chapter.