9.4 Design Methodology
327
of software testing, including code checking, dynamic testing on hard platform and soft platform, black-box test, white-box test and etc. Generally, it
was better to apply combination of multiple methods. It was one of the most
used and most effective methods to use special test device or simulation device
to interconnect with the object to be tested. By application of the latest technology of current ground computers to establish a test system, the level and
effectiveness of software test automation were improved.
The development process of OBDH SMU software of the Chang’E-3 lunar lander
applied a waterfall model. The data flow oriented method was applied when the
software was developed. According to requirements of software users, each functional requirement was decomposed one by one, and the task modules were classified
according to flow direction.
The application software used the interface and service provided by the system
software and was finally compiled together with the system software, which was
stored in PROM of SMU. After the hardware was powered on or restarted, the system
software was loaded and executed. When the CPU register and software module was
initialized by the system software, it was running in the multitasking mode. The
operation of application software was initialized by switching the execution flow to
the session of application software. The application software implemented creation
of multiple tasks through system calls and was running by the support of the system
software scheduling. The connections with the system software was established in
the form of system calls, as well as the creation of message queues, interrupts service
routines, and timer management, so as to coordinate all tasks to implement all the
functions of application software.
The OBDH SMU software of the Chang’E-3 lunar lander was a multi-task and
large-scale spacecraft software. Besides the function of CTU software in traditional
OBDH subsystem, the SMU software should also provide the functions of RTU
software and data multiplexer software. Beside functions of the traditional OBDH
software such as telemetry, telecommand, program control, data processing, selfmanagement and routine management, the OBDH SMU software should also be
responsible for special control and management functions of the lunar lander, such
as the unfolding/folding of the solar panels, deployment of the lunar rover, selfmonitoring and control of the high-pressure latch valve, special thermal control of
the orbit control engine, directional antenna pointing control and etc. The SMU
application software was upgraded to abstract level from system level design. The
task flow diagram was established. The task modules and interrupt service program
were classified based on system level optimization with limited hardware resources.
The methods including cooperative design of hardware and software, accurate
timing division and concurrent operation process setting were applied to implement rational scheduling and efficient operation. A lot of complex functions were
integrated in a software configuration which satisfied the complex functional and
327
of software testing, including code checking, dynamic testing on hard platform and soft platform, black-box test, white-box test and etc. Generally, it
was better to apply combination of multiple methods. It was one of the most
used and most effective methods to use special test device or simulation device
to interconnect with the object to be tested. By application of the latest technology of current ground computers to establish a test system, the level and
effectiveness of software test automation were improved.
The development process of OBDH SMU software of the Chang’E-3 lunar lander
applied a waterfall model. The data flow oriented method was applied when the
software was developed. According to requirements of software users, each functional requirement was decomposed one by one, and the task modules were classified
according to flow direction.
The application software used the interface and service provided by the system
software and was finally compiled together with the system software, which was
stored in PROM of SMU. After the hardware was powered on or restarted, the system
software was loaded and executed. When the CPU register and software module was
initialized by the system software, it was running in the multitasking mode. The
operation of application software was initialized by switching the execution flow to
the session of application software. The application software implemented creation
of multiple tasks through system calls and was running by the support of the system
software scheduling. The connections with the system software was established in
the form of system calls, as well as the creation of message queues, interrupts service
routines, and timer management, so as to coordinate all tasks to implement all the
functions of application software.
The OBDH SMU software of the Chang’E-3 lunar lander was a multi-task and
large-scale spacecraft software. Besides the function of CTU software in traditional
OBDH subsystem, the SMU software should also provide the functions of RTU
software and data multiplexer software. Beside functions of the traditional OBDH
software such as telemetry, telecommand, program control, data processing, selfmanagement and routine management, the OBDH SMU software should also be
responsible for special control and management functions of the lunar lander, such
as the unfolding/folding of the solar panels, deployment of the lunar rover, selfmonitoring and control of the high-pressure latch valve, special thermal control of
the orbit control engine, directional antenna pointing control and etc. The SMU
application software was upgraded to abstract level from system level design. The
task flow diagram was established. The task modules and interrupt service program
were classified based on system level optimization with limited hardware resources.
The methods including cooperative design of hardware and software, accurate
timing division and concurrent operation process setting were applied to implement rational scheduling and efficient operation. A lot of complex functions were
integrated in a software configuration which satisfied the complex functional and