Other Satellite Navigation Systems - Understanding GPS: Principles and Applications - page 617

the Double Star Positioning System. The Chinese indicated the system would sup-
port mapping, aeronautics, aviation, navigation, mining, shipping, emergency
disaster relief applications, and national defense [37].
The first BeiDou satellite was launched in October 2000, and the second in
December 2000. The third BeiDou satellite was launched in May 2003. There are
some Chinese press references to a fourth spare satellite, but these are unconfirmed
[42].
After the launch in late 2000, the system went through an on-orbit validation.
In 2001, the Chinese government issued a series of contracts for development and
operation of the military fleet management service, the civil fleet management ser-
vice, the SBAS ground-monitoring network, and for various types of user equip-
ment. The RDSS system also went through a series of system validations from 2001
to 2002. In December 2001, the Chinese began advertising user equipment for the
BNTS. However, to date, there were only a few claims of sales of the user sets to the
Chinese military. The Chinese contractor completed the military service in late
2003. The civil service was declared operational in conjunction with the launch of
the third satellite in June 2003. As stated earlier, the status of Chinese SBAS is
unknown [43-45].
11.2.4 Organization Structure
The BeiDou system is owned and operated by the Chinese government as a dual-use
system. However, the Chinese have not provided specific details or an official point
of contact within the Chinese government for BeiDou. The Chinese identify two pri-
vate companies under contract from the government providing the BeiDou RDSS
positioning and fleet-management services. ChinaTopComm operates the civil
fleet-management services. BDStar operates the military fleet-management services.
BDStar has also expressed interest in developing commercial services in the future.
The operators of the BeiDou SBAS services have not been made known to the
international community [43, 44].
11.2.5 Constellation and Orbit
BNTS is composed of three satellites. The first two satellites, launched in October
and December 2000, were placed at 80ºE and 140ºE longitude on the geostationary
belt and carry a RDSS transponder payload. The RDSS transponders operate using
an L-band (1,610-1,626.5-MHz) uplink and S-band (2,483.5-2,500-MHz)
downlink. The third BeiDou-1 satellite was launched in May 2003 and placed at
110ºE longitude. It carries both an RDSS and SBAS transponder payload. The SBAS
payload operates in the GPS L1 and L2 radio frequency bands and is likely used to
augment both GPS and GLONASS [46, 47].
11.2.6 Spacecraft
The BNTS satellites use the Chinese standard DJS-1 spacecraft bus, which is also
used by Chinese DFH-3, CHINASAT, Zhongxing-20, and Zhongxing-22 commu-
nications satellites. The spacecraft uses a box-shaped bus with the dimensions of