404
5 X-ray Pulsar-Based Navigation: Theories and Experiments
Table 5.9 (continued)
GPS satellite series Performance improvement
Number of satellite-launched
Block IIR-M
The Block IIR-M satellites are the
modernized series of the Block IIR
satellites. The new military M-codes are
added in the satellites, broadcasting them at
the L1 and L2 frequencies. In addition, the
civil ranging L2C codes are added at the L2
frequency. Compared with the P(Y) code,
the M-code has stronger transmitting
power, anti-jamming capability and security
performance, and is conducive to direct
acquisition
8
Block IIF
The Block IIF satellites are the follow-up
series of the Block IIR satellites, in which
the civil frequency L5 (1176.45 MHz) is
added to ensure the safety in civil aviation
application. Furthermore, the flexible
software and hardware designs of the
payload are adopted to enhance the
cross-link data processing, inter-satellite
communication, and high-speed uplink and
downlink data transmission capabilities
12
Block III-A
The Block III satellites are the new
generation GPS satellite series, with the
design lifetime of 15 years, to meet higher
demands of both military and civilian users.
According to the different performance
improvements, the GPS III satellites are
divided into three types of A, B and C. The
Block IIIA satellites deliver significant
improvements over current GPS satellites,
such as adding the new international civil
signal (L1C) and increasing the M-code
anti-jamming power with full Earth
coverage for military users
3
It is imagined that the navigation satellite system serving for the near-earth space
is copied to the deep-space exploration and interstellar flight applications, and the
navigation constellations will be established at some feature positions in space, such
as the Earth–Moon Lagrange points, the Moon and Mars, so as to provide the navigation information for the deep-space probes and interplanetary vehicles. On the one
hand, the mechanism of the navigation satellite system has not changed substantially; on the other hand, the precise TT&C for the navigation constellation, as well
as the long-term maintenance cost and economic benefits will become challenging
problems. Therefore, constructing the dedicated navigation satellite system serving
for deep-space exploration messions is also not the development orientation of the
3G-NAV system.
5 X-ray Pulsar-Based Navigation: Theories and Experiments
Table 5.9 (continued)
GPS satellite series Performance improvement
Number of satellite-launched
Block IIR-M
The Block IIR-M satellites are the
modernized series of the Block IIR
satellites. The new military M-codes are
added in the satellites, broadcasting them at
the L1 and L2 frequencies. In addition, the
civil ranging L2C codes are added at the L2
frequency. Compared with the P(Y) code,
the M-code has stronger transmitting
power, anti-jamming capability and security
performance, and is conducive to direct
acquisition
8
Block IIF
The Block IIF satellites are the follow-up
series of the Block IIR satellites, in which
the civil frequency L5 (1176.45 MHz) is
added to ensure the safety in civil aviation
application. Furthermore, the flexible
software and hardware designs of the
payload are adopted to enhance the
cross-link data processing, inter-satellite
communication, and high-speed uplink and
downlink data transmission capabilities
12
Block III-A
The Block III satellites are the new
generation GPS satellite series, with the
design lifetime of 15 years, to meet higher
demands of both military and civilian users.
According to the different performance
improvements, the GPS III satellites are
divided into three types of A, B and C. The
Block IIIA satellites deliver significant
improvements over current GPS satellites,
such as adding the new international civil
signal (L1C) and increasing the M-code
anti-jamming power with full Earth
coverage for military users
3
It is imagined that the navigation satellite system serving for the near-earth space
is copied to the deep-space exploration and interstellar flight applications, and the
navigation constellations will be established at some feature positions in space, such
as the Earth–Moon Lagrange points, the Moon and Mars, so as to provide the navigation information for the deep-space probes and interplanetary vehicles. On the one
hand, the mechanism of the navigation satellite system has not changed substantially; on the other hand, the precise TT&C for the navigation constellation, as well
as the long-term maintenance cost and economic benefits will become challenging
problems. Therefore, constructing the dedicated navigation satellite system serving
for deep-space exploration messions is also not the development orientation of the
3G-NAV system.