中文摘要：

为提高卫星信息传输过程中窃听难度，提出一种基于方向一极化状态调制技术的双极化卫星多输入多输出（multiinputmultioutput，MIMO）安全传输方法。该方法将传输信号的极化状态与接收机方位信息相结合，实现信号差异性发射，增大非期望方向接收机解调信息的难度。理论分析和仿真结果表明，相比于传统调制技术，基于方向一极化状态调制技术为双极化卫星MIMO系统的信息传输提供了一种更加安全的传输方案。

英文摘要：

A secure transmission method for dual-polarized satellite multiple input multiple output （MIMO） systems based on the directional polarization state modulation technology is proposed. Indeed, the transmitted signal＇s polarization state （PS） is linked with the azimuth angle, thus the PS is changed off the desired direc- tion. In this way, it is more difficult for receivers in undesired directions to demodulate any useful information in the received signal. Theoretical analysis and simulation results demonstrate the proposed technique offers a bet- ter secure transmission performance in dual-polarized satellite MIMO systems.