GPS/INS超紧组合载波跟踪环路最优带宽在线设计

在全球定位系统和惯性导航系统组成的超紧耦合系统中，卫星信号的跟踪性能直接取决于载波跟踪环路的带宽。为提高最优带宽的计算精度，在对惯导辅助下载波跟踪环路跟踪特性进行分析的基础上，详细推导了载波多普勒频率估计误差、多普勒频率变化率估计误差的计算方式，建立了惯导辅助下的环路跟踪误差模型；在实时估计跟踪载噪比的基础上，应用离散牛顿二阶梯度法迭代解算最优带宽，并进行实时调整。仿真结果表明，所设计最优带宽迭代解算方法的计算精度能够在11次迭代内达到99.6%，以此作为环路的带宽，能够在弱信号、辅助信息精度较低的情况下有效提高环路的跟踪精度。

Online design of optimal carrier tracking loop bandwidth for tightly coupled GPS/INS

In GPS(Global Positioning System)/INS(Inertial Navigation System) ultra tight coupling system, the tracking performance of satellite signal depends directly on the bandwidth of carrier tracking loop. In order to improve the computation accuracy of optimal bandwidth, on the basis of analyzing the tracking characteristics of INS assisted PLL(Phase Locked Loop), the deduction of the assisting error of carrier Doppler shift and its rate of change was performed, and the loop tracking error model aided by INS was established. With the real time estimation of tracking carrier to noise ratio, the discrete second order Newtonian iterative method was applied, and the optimal bandwidth was calculated and adjusted in real time. The simulation results show that the optimal bandwidth iterative method achieves 99.6% accuracy in 11 iterations. When the optimal bandwidth is used as the real time bandwidth of the loop, the tracking accuracy of the loop can be effectively improved under the condition of weak signal and low assisting information accuracy.