轨道预测辅助GPS载波跟踪技术用于低轨道卫星定位研究

针对低轨道卫星及其特定的运动环境,研究了星载GPS接收机载波跟踪问题。基于卫星轨道可模化、可预测的特性,提出了利用预测卫星轨道计算多普勒频移,并用于辅助载波环路跟踪的新方法。该方法有效地降低了低轨道卫星GPS信号跟踪中的动态,从而在跟踪过程中可以采取降低环路阶数、减小环路带宽、增加预检测积分时间这几种措施来提高环路跟踪弱信号的能力,有助于提高低轨道卫星的定位性能。

The Study of Orbit Forecast Assisted GPS Carrier Tracking Technology for LEO Satellite Positioning

In view of low earth orbit satellite and its specific dynamic environment, the method of carrier tracking for space-borne GPS receiver has been studied. As the satellite''s orbit can be modeled and forecast, a method which aids the carrier tracking loop by using the doppler frequency shift obtained through the forecast approach is proposed. This method can effectively reduce the dynamics in the GPS signal tracking of low-earth orbit (LEO) satellite, during which the loop orders and bandwidth can be reduced, and the integration time of pre-detection can be increased. And by these measures, the loop''s ability of tracking weak signal will be greatly enhanced, and the positioning performance of satellite can be improved greatly.