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复杂环境下导航接收机的连续可用性一直是卫星导航领域的研究重点。针对矢量跟踪环动态适应性不够和误差在通道间传播的问题,提出一种鲁棒全球导航卫星系统(GNSS)矢量跟踪环。基于各通道的伪距、伪距率和伪距加速度状态量构建扩展卡尔曼滤波器(EKF),通过灵活设置过程噪声方差阵,实现跟踪通道的耦合与解耦;采用基于极大似然估计器(MLE)的鉴别器生成码延迟和载波频率偏差观测量;利用滤波值修正并预测伪距率来控制本地数控振荡器(NCO),实现环路的闭合。仿真结果表明,本文设计的矢量跟踪环在保证环路相互辅助的基础上,避免了衰减通道误差在通道间的传播,可以对被遮挡信号保持稳定跟踪,鲁棒性优于传统矢量延迟频率锁定环。
The continuous availability of navigation receivers in complex environments has been the focus of research in the field of satellite navigation. Aiming at the problem that the dynamic adaptability of the vector tracking loop is not enough and the error propagates among the channels, a robust global navigation satellite system (GNSS) vector tracking loop is proposed. Based on pseudoranges, pseudoranges and pseudorange acceleration state quantities of each channel, an extended Kalman filter (EKF) is constructed. Coupling and decoupling of the tracking channels are achieved by setting the process noise variance matrix flexibly. Maximum likelihood estimation (MLE) discriminator generated code delay and carrier frequency deviation observation; use the filter value to correct and predict the pseudo-range to control the local numerically controlled oscillator (NCO), to achieve the closure of the loop. The simulation results show that the vector tracking loop designed in this paper can avoid the propagation of the attenuation channel error between the channels while ensuring the mutual aid of the loops and can keep the track of the blocked signal stably and has better robustness than the traditional vector delay frequency locking ring.