一种适用于高轨空间的GNSS矢量跟踪方案设计

The availability of Global Navigation Satellite System (GNSS) signal in high-orbit space deteriorates, which puts forward higher requirements for the signal tracking performance of GNSS receiver. The received power characteristics of GNSS signal in high-orbit space are analyzed by using the GNSS signal transmission link model. The applicability of two typical tracking loops, scalar-tracking and vector-tracking, in high-orbit space is compared. A GNSS vector tracking scheme for high-orbit space is designed. In this scheme, the measurement noise covariance is determined by estimating the carrier-to-noise ratio, and then the measurement information of each channel is weighted to obtain high-precision navigation parameters. The process noise covariance is determined according to the dynamic performance of the high-orbit spacecraft, and the orbit dynamic model is used to make a one-step prediction of the navigation parameters, thereby predicting the signal tracking parameters of each channel to achieve joint tracking of all channels. Simulation results show that the designed scheme can realize the assistance of strong signals to weak signals tracking in high-orbit space, so as to improve the tracking performance and availability of weak signals in high orbit space. In addition, the designed scheme also has a certain bridging ability to signal outage.