基于单光子量子通信，提出了一种通过自由空间进行信息传输的全球卫星量子通信方案，采用地面与卫星间、卫星与卫星间通信为主，地面与地面间通信为辅的传输方式实现全球通信覆盖。分析了大气信道、背景噪声以及地磁场法拉第效应对波长选择的影响和通信方案的可行性，并对通信链路衰减需求进行了仿真分析，仿真结果表明此通信方案能够满足链路需求，完成通信。

A global quantum satellite communication scheme that transmits information by single photon through free space is proposed. To reduce the influence of atmosphere, this system mainly adopts ground to satellite communication and satellite to satellite communication, assisted with the ground to ground communication. Analysis is made to the impact of the atmospheric channel, the background noise and the Faraday effect of geomagnetic field on the choice of wavelength, and the feasibility of the communication scheme is studied. Simulation analysis is made to this scheme's link attenuation requirements. The result shows that the communication scheme can satisfy the requirement of the communication link.