Other Satellite Navigation Systems - Understanding GPS: Principles and Applications - page 626

The intent is to bring the navigation service on line in coordination with GPS
upgrades. A U.S.-Japanese working group was established in October 2002 and is
working toward this goal. When the GPS-QZSS Technical Working Group met in
January 2004, problems related to interoperability were addressed through formal
documents on configuration management [66, 67].

11.3.3 Organizational Structure
Support from industry in the earliest stages of planning in the late 1990s was focused
on the goal of improving mobile communications in the rural areas as well as the
urban canyons of metropolitan areas. Joining this activity, the government devel-
oped a plan to provide through the public sector improvements to the satellite navi-
gation service available from GPS. A variety of commercial, economic, and political
influences have swayed the program during the course of development. The alloca-
tion of resources and responsibilities for spacecraft deployment as well as operation
of the constellation on a daily basis remains a topic of discussion. Progress in the
QZSS program is nearly assured, owing to the clear benefits it brings in stimulating
the national space technology industries. This progress may occur slowly, however,
as the various stakeholders sort out the opportunities it presents. A directive coming
from the Japanese Council on Science Technology Policy on September 9, 2004,
gave further structure. The four basic ministries involved, as well as the major indus-
tries comprising the Advanced Space Business Corporation hope to sort out the par-
ticulars. The QZSS program has been under development long enough to see both
the founding agency the Communications Research Laboratory (CRL) and Japan's
National Aeronautics and Space Development Agency renamed and reorganized
into the National Institute of Information and Communications Technology and the
Japanese Aerospace Exploration Agency, respectively [68, 69].

11.3.4 Constellation and Orbit
To meet the requirements for having a system with satellites operating predomi-
nantly over Japan, an inclined geosynchronous or semisynchronous orbit is being
planned. The inclination will give, for at least part of the orbit, the desired high
viewing altitude over the 2,500-km range stretch of Japanese islands running from
27ºN to 45ºN. The synchronous orbit will keep the satellites in the appropriate lon-
gitude so they are in view from Japan. In the case of GPS, the difficulty has been in
accessing four visible satellites in a geometry that is optimal for an accurate naviga-
tion fix, as seen from such terrain. Additionally, the QZSS concept will alleviate dif-
ficulties in using communications services provided by geostationary satellites,
which have low elevation of no higher than 45º when viewed from central Japan
[65, 70]. 1
The first concept for an indigenous Japanese constellation of geosynchronous sat-
ellites in inclined orbits producing the figure 8 pattern for regional access was pro-
moted by CRL for communications alone. In fact the plan in 1998 was for an
“EFSAT” (eight-figure satellite) system. Though there were several advantages, the
idea was to provide high-quality communications services to Japan and Australia

1. Okinawa is at 27º; Iwo Jima, off somewhat to the East, is actually further south yet at 25º.