等离子体对GPS信号载噪比的影响

飞行器再入过程产生等离子体,等离子体中电子密度的变化对电磁波信号造成幅度衰减和相位偏移,严重时导致通信中断。理论分析了等离子体对GPS信号载噪比的影响;利用实验室环境下的等离子体模拟装置,设计了GPS二键相控(BPSK)调制信号透过等离子体的地面模拟方案,进行了等离子体对GPS接收机性能影响的实验研究,获得了不同电子密度下的衰减和导航信号载噪比的数据。实验结果与理论分析一致,不仅证明了等离子体下衰减与导航信号载噪比的变化是一致的结论,而且验证了实验方法的有效性。

Effect of plasma on C/N0 of GPS signal

The plasma induced in the reentry can potentially degrade electromagnetic system through amplitucle attenuation and phase shift by means of the varying electron density which vastly disturbs the reentry vehicle''s communication, navigation and control, even produces the blackout. The relationship between the plasma and the GPS C/N₀ is theoretically analyzed. Utilizing a large volume uniform plasma generator with long duration in the ordinary laboratory, a design of GPS binary phase shift keying (BPSK) signal propagation in plasma is made and an experiment of the plasma on GPS receiver is conducted to obtain the attenuation and C/N₀ with different electron densities. The results indicate that attenuation is the same as the reduction of the C/N₀. And the experimental values support the theoretical results which show the validity of the experimental method.