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7 Guidance, Navigation and Control Technology …
(2) Otherwise, if the calculated control torque was less than the attitude control
torque that could be provided by single 150 N thruster, the pulse width of the
10 N thrusters were set to zero, and the pulse width modulation of the single
150 N thruster was performed.
(3) Otherwise, pulse width of 10 N thrusters were set to zero, pulse width
modulation of double 150 N thrusters was performed.
7.6 Testing and Verification
As any other projects, design verification process could not be separated from the
development process of any space program. Design verification is an important part
of the spacecraft development process and is integrated with the design, manufacture
and assembly process during modern spacecraft production phase. The success and
stereotypes of any space theories requires the support of advanced design verification
technology.
The lunar surface environment faced by the lunar lander was a brand-new challenge. It WAs necessary to conduct complete and comprehensive design verification
on the ground. According to the components features, navigation sensors calibration, subsystem flight test by airplane and semi-physical simulation were carried on
during the development of GNC subsystem.
7.6.1 Key Navigation Sensors Calibration
1. Calibration of 3-D Laser Imaging Sensor
1) Test objective
In the calibration test, the laser ranging data of the 3-D Laser Image Sensor at
multiple angles with no scanning of the motor was obtained, and the system error
was compensated by the distance calibration device so that the slant range accuracy
of the sensor satisfied the design requirements.
2) Test method
Ten test boards were placed at a depth of approximately 20 m in the test field, 12 or 13
test points were uniformly placed on each test board, and 4 test points were placed on
the head of the sensor. The coordinates of all test points were measured with a total
station. The measurement results of the 3-D Laser Imaging Sensor were compared
with the total station results. The Laser 3-D Image Sensor outdoor calibration field
is shown in Fig. 7.17.
2. Calibration of Optical Image Sensor
1) Test objective
7 Guidance, Navigation and Control Technology …
(2) Otherwise, if the calculated control torque was less than the attitude control
torque that could be provided by single 150 N thruster, the pulse width of the
10 N thrusters were set to zero, and the pulse width modulation of the single
150 N thruster was performed.
(3) Otherwise, pulse width of 10 N thrusters were set to zero, pulse width
modulation of double 150 N thrusters was performed.
7.6 Testing and Verification
As any other projects, design verification process could not be separated from the
development process of any space program. Design verification is an important part
of the spacecraft development process and is integrated with the design, manufacture
and assembly process during modern spacecraft production phase. The success and
stereotypes of any space theories requires the support of advanced design verification
technology.
The lunar surface environment faced by the lunar lander was a brand-new challenge. It WAs necessary to conduct complete and comprehensive design verification
on the ground. According to the components features, navigation sensors calibration, subsystem flight test by airplane and semi-physical simulation were carried on
during the development of GNC subsystem.
7.6.1 Key Navigation Sensors Calibration
1. Calibration of 3-D Laser Imaging Sensor
1) Test objective
In the calibration test, the laser ranging data of the 3-D Laser Image Sensor at
multiple angles with no scanning of the motor was obtained, and the system error
was compensated by the distance calibration device so that the slant range accuracy
of the sensor satisfied the design requirements.
2) Test method
Ten test boards were placed at a depth of approximately 20 m in the test field, 12 or 13
test points were uniformly placed on each test board, and 4 test points were placed on
the head of the sensor. The coordinates of all test points were measured with a total
station. The measurement results of the 3-D Laser Imaging Sensor were compared
with the total station results. The Laser 3-D Image Sensor outdoor calibration field
is shown in Fig. 7.17.
2. Calibration of Optical Image Sensor
1) Test objective