Abstract:  The current design of GEO orbit satellite onboard computer was analyzed, including memory design, data sharing design and bus protocol design. In view of the shortcomings of the above three aspects, a CPU minimum system memory optimization design method was proposed, which solves the memory chip selection problem. A “memory + FPGA circuit” design method was proposed realizing data sharing between nominal and redundancy onboard computer.An adaptive bus protocol design method was proposed which makes the 1553B bus protocol more general. The design method proposed has been applied in the next generation high capability communication satellite onboard computer in China, and promising results have been obtained. It also provides a new way of thinking for the followup optimization design of the onboard computer.

Key words: GEO satellite, onboard computer, memory, data sharing, bus protocol