Abstract:  The microsatellite avionics system, which carries out most of the functions of the satellite, is the center of satellite mission processing and control. In the future, new intelligent applications, satellite cluster applications, communications services and other requirements will also be implemented by satellite, which puts forward new requirements for avionics system. The typical microsatellite avionics systems abroad were analyzed. It has the characteristics of high function density. Most functions are concentrated in one computer and satellite functions are software defined. The integrated structure of avionics system based on software definition was designed. The hardware was modularized with highly integrated design, and the software was layered and componentized. The functions and services of each layer were realized by means of software definition components. High functional density avionics system is composed of a general high performance hardware platform and various kinds of loadable APP software. In addition to traditional functions, it can also be extended to autonomous mission management, intersatellite networking and payload management functions. Not only the integration and functional density of satellites have been greatly improved, but also the functional reconstruction of satellites has been realized, achieving the goal of multifunctions in one satellite. It can provide reference for future applications of constellation network.

Key words: microsatellite, avionics system, high functional density, software defined, system design