10.5 Testing and Verification
363
The test results showed that the transmission characteristics of telecommunication
link were affected by the distance between two lunar probes and the terrain. The actual
loss of UHF telecommunication link was consistent with the simulation analysis of
telecommunication link. The model applied in the simulation analysis was consistent
with actual results.
10.6 Summary
The telemetry/telecommand and telecommunication subsystem was designed to
implement the information transmission between the lunar lander and the ground, as
well as the lunar lander and the lunar rover in the Chang’E-3 lunar mission, which
was also an important part of orbit determination. The characteristics, design and
verifying of the onboard telemetry/telecommand and telecommunication technologies was described according to mission features of lunar landing exploration with
development status of telemetry/telecommand and telecommunication technology
in deep space mission.
Along with continuous improvement of space science and technology, deep space
exploration such as lunar exploration is constantly extending. Higher requirements
for deep space telemetry/telecommand and telecommunications are come up. The
development trends of telemetry/telecommand and telecommunication technology
in future deep space mission include the following aspects.
(1) Software Radio. At the end of twentieth century, the concept of software radio
was come up for the first time. The central idea was to construct a general hardware platform with openness, standardization and modularization to implement various telecommunication functions such as modulation/demodulation,
data format, encrypt mode and telecommunication protocol by software. At
the same time, the broadband A/D and D/A was made to be near the radio
frequency and extended from the baseband to intermediate frequency or radio
frequency, so as to develop a new generation of wireless telecommunication
system with high flexibility and openness. Once the concept of software radio
was put forward, it gained wide attention in radio field around the world, and
became the future development trend of telecommunication and even radio
technology [15].
(2) Large aperture antenna. The main challenge in deep space telecommunications
is that the RF signal is usually very weak due to long distances in deep space
mission when it reaches the receiver. In order to increase the power utilization as
much as possible when the signal power is limited, the method can be selected
to increase the antenna aperture. The antenna gain can be improved when the
antenna aperture increases. The antenna gain is an important specification that
shows the capability of the antenna to concentrate and radiate energy [16].
(3) Ka band telecommunication. The telecommunication in deep space exploration has the characteristics of long distance and large path loss,
363
The test results showed that the transmission characteristics of telecommunication
link were affected by the distance between two lunar probes and the terrain. The actual
loss of UHF telecommunication link was consistent with the simulation analysis of
telecommunication link. The model applied in the simulation analysis was consistent
with actual results.
10.6 Summary
The telemetry/telecommand and telecommunication subsystem was designed to
implement the information transmission between the lunar lander and the ground, as
well as the lunar lander and the lunar rover in the Chang’E-3 lunar mission, which
was also an important part of orbit determination. The characteristics, design and
verifying of the onboard telemetry/telecommand and telecommunication technologies was described according to mission features of lunar landing exploration with
development status of telemetry/telecommand and telecommunication technology
in deep space mission.
Along with continuous improvement of space science and technology, deep space
exploration such as lunar exploration is constantly extending. Higher requirements
for deep space telemetry/telecommand and telecommunications are come up. The
development trends of telemetry/telecommand and telecommunication technology
in future deep space mission include the following aspects.
(1) Software Radio. At the end of twentieth century, the concept of software radio
was come up for the first time. The central idea was to construct a general hardware platform with openness, standardization and modularization to implement various telecommunication functions such as modulation/demodulation,
data format, encrypt mode and telecommunication protocol by software. At
the same time, the broadband A/D and D/A was made to be near the radio
frequency and extended from the baseband to intermediate frequency or radio
frequency, so as to develop a new generation of wireless telecommunication
system with high flexibility and openness. Once the concept of software radio
was put forward, it gained wide attention in radio field around the world, and
became the future development trend of telecommunication and even radio
technology [15].
(2) Large aperture antenna. The main challenge in deep space telecommunications
is that the RF signal is usually very weak due to long distances in deep space
mission when it reaches the receiver. In order to increase the power utilization as
much as possible when the signal power is limited, the method can be selected
to increase the antenna aperture. The antenna gain can be improved when the
antenna aperture increases. The antenna gain is an important specification that
shows the capability of the antenna to concentrate and radiate energy [16].
(3) Ka band telecommunication. The telecommunication in deep space exploration has the characteristics of long distance and large path loss,