Research On Embedded Space Camera Controller Based On DSP

With the development of satellite technology, short design cycle and low cost small satellite applications are increasingly being used, and now has been successfully used in scientific research, mapping, military, communications and other fields. Space Camera controller as a controller system of satellite, links the camera system and the satellite platform, and responsibles for controlling and operation management of the camera features. In order to meet the requirements of small satellite system, we need design a simple, real-time, high reliability, and low cost camera controller which has high data processing ability.This article comes from the mission requirements of space mapping camera controller system.It introduced the design method of camera controller based on DSP and FPGA, detailed the specific implementation of the camera controller hardware system and functional modules(including mode control, communications control, focus control, etc.).And then analyzed the merit of CAN bus applied in the small satellite communication system, introduced the design of the DSP and CAN bus communication circuit. RS-422 communication circuits between camera controller and imaging unit and coding unit were introduced. Finally USB communication circuit used in ground testing system of camera controller was designed.For software development, software program based on DSP platform of the space camera image motion velocity, mode control, etc, was designed. And the design implementation of asynchronous serial port (UART), logic interface control and interrupt generation based on FPGA were described. Then it analyzed features and working principle of embedded real-time operating system-μC/OS-Ⅱ. The task scheduling and task synchronization of theμC/OS-Ⅱsystem were introduced when applied in the actual systems. In this paper, theμC/OS-Ⅱsystem was introduced into the camera control system, and was divided into multipleμC/OS-Ⅱsystem tasks according to the function modules of camera controller. This paper discussedμC/OS-Ⅱtasks programming and synchronization methods. Additionally it developed a CAN communication protocol, achieved the reliable communications with camera controller. USB firmware procedures and ground test application program were written that provided the man-machine interface between users and the camera control system conveniently for ground testing. Finally, the reliability and real-time ability of the system software was analyzed briefly.In the last, the camera control system testing and experimental results were given, and research work in this thesis was summarized. The problem that needed to be solved for future was analyzed. The further work was prospected, too.