基于卡尔曼滤波的抗电离层闪烁跟踪算法研究

Study on Tracking Algorithm Against Ionospheric Scintillation Effects Based on Kalman Filter

针对电离层闪烁可引起星载GPS接收机传统锁相环(PLL)跟踪环路测量误差增大从而降低接收机定位及测速精度的问题,引入自适应带宽环路,提出一种基于卡尔曼滤波的抗电离层闪烁载波跟踪环路,给出了卡尔曼滤波跟踪环路结构与建模过程,主要包括系统模型与观测模型的建模过程。采用AJ-Stanford电离层闪烁模型生成闪烁数据,仿真分析不同强度的幅度闪烁,比较基于卡尔曼滤波的跟踪环路与传统PLL跟踪环路的性能,卡尔曼环路的鉴相值标准差与载波相位误差均比传统PLL环路小。仿真结果表明:当幅度闪烁时,基于卡尔曼滤波的跟踪环路鲁棒性与跟踪精度均优于传统的PLL环路。

Ionospheric scintillation can increase the measurement error of the traditional PLL(phase locked loop)tracking loop of spaceborne GPS(global positioning system)receiver,so as to reduce the precision of position and velocity measurement.Aiming at this problem,the adaptive bandwidth loop is introduced and a carrier tracking algorithm against ionospheric scintillation based on Kalman filter is proposed.Structure of carrier tracking loop based on Kalman filter and modeling process of system model and observation model are given.AJ-Stanford model is selected as the simulation model and used to generate the ionospheric scintillation data.And simulation is carried out with different amplitude scintillations.Standard deviation of discriminator output and carrier phase error of carrier tracking algorithm based on Kalman filter are smaller than those of traditional PLL.Results show that tracking precision and robustness of the carrier tracking algorithm based on Kalman filter are better than those of traditional PLL with different amplitude scintillations.