根据实际中自旋导弹GPS接收天线相位中心与导弹自旋几何中心的不一致性,建立弹载天线坐标系。推导弹体自旋条件下接收的GPS卫星信号的附加多普勒频移变化规律,验证弹体自旋对接收信号的影响。提出一种新的GPS信号跟踪环路设计方法,以消除附加多普勒频率对跟踪的影响。该设计在传统环路基础上加入旋转跟踪环,实现对弹体自旋转速的估计,利用转速信息辅助环路跟踪。经过计算机仿真验证,新环路载波相位跟踪误差较传统环路显著减小,表明该设计能够获得更佳的信号跟踪性能。
According to the inconsistency between the receiver antenna phase center and the geometric center of the actual spinning missile, an onboard antenna coordinate system is established. In order to verify the effects of spinning on receiving signal, the additional Doppler shift model of receiving GPS signal is derived. A new tracking loop configuration of GPS receiver is proposed to eliminate the influence of additional Doppler shift which is caused by spinning. The new loop uses a spinning tracking loop to estimate the spinning rates of missile and improve the performance of conventional tracking loop. The new loop was verified through computer simulation. The results show that the new configuration provides smaller phase tracking errors and has a better tracking performance.